blowdown safety valve manufacturer

The pressure below the valve must increase above the set pressure before the safety valve reaches a noticeable lift. As a result of the restriction of flow between the disc and the adjusting ring, pressure builds up in the huddling chamber. The pressure now acts on an enlarged disc area. This increases the force Fp so that the additional spring force required to further compress the spring is overcome. The valve will open rapidly with a "pop", in most cases to its full lift.

Overpressure is the pressure increase above the set pressure necessary for the pressure relief valve to achieve full lift and capacity. The overpressure is usually expressed as a percentage of the set pressure. Codes and standards provide limits for the maximum overpressure. A typical value is 10%, ranging between 3% and 21% depending on the code and application.

In most applications a properly sized pressure relief valve will decrease the pressure in the vessel when discharging. The pressure in the vessel will decrease at any subsequent point, but not later than the end of the upset situation. A decreasing pressure in the vessel will lower the force Fp. At set pressure however the flow is still acting on the enlarged disc area, which will keep the valve open. A further reduction in pressure is required until the spring force Fs is again greater than Fp and the pressure relief valve begins to reclose. At the reseating pressure the disc will touch the nozzle again and the pressure relief valve recloses.

Blowdown is the difference between set pressure and reseating pressure of a pressure relief valve expressed as a percentage of set pressure. Typical blowdown values as defined in codes and standards are -7% and -10%, ranging from -4% to -20% depending on the code and service (steam, gas or liquid).

The primary purpose of a blowdown valve is to regulate a constant flow of steam/fluid at an elevated differential pressure and also to remove dirt, sediment, and limescale.

Blowdown valves are used either continuously or intermittently depending on the service requirements and play an important role in fossil fuel boilers to remove dissolved solids from the boiler water. Generally, only one blowdown valve is used in a boiler. If more than one blowdown valve is used in a boiler, the two valves are often used in series to minimize erosion. In this design, one valve acts as the shutoff valve, and the other valve acts as the drain valve. The shutoff valve is usually opened first and closed last. To minimize erosion of the disc and seat, both valves are opened quickly and simultaneously. Most importantly, care should be taken to avoid trapping rust particles in the valve during the drainage process. This is accomplished by opening the valves again so that any remaining rust particles are flushed out with the next passage of steam through the piping. Whenever a boiler is taken out of service for maintenance, the bottom drain valve is usually rebuilt or replaced.

Generally, we classify blowdown valves into two categories, continuous blowdown(CBD) valves, and intermittent blowdown (IBD) valves, since the intermittent blowdown valve works close to the bottom of the boiler, we also call it a bottom blowdown valve.

The continuous blowdown valve (CBD) is designed to operate in a constant open position to maintain the TDS level in the boiler ladle by continuously releasing water from the boiler water surface through the blowdown tap. Some engineers also name this valve a surface blowdown valve.

The purpose of the bottom blowdown valve is to remove boiler sediment to keep the boiler water in compliance with manufacturing standards to improve the efficiency and performance of the boiler.

The function of the intermittent blowdown valve is to release accumulated sludge and sewage through a drain near the bottom of the boiler at regular periods, usually with a predetermined time cycle. There is a special requirement for the bottom blowdown valve to ensure that the valve can be tightly closed after repeated draining actions.

In boiler operation, the deposition of impurities is highest at the point where liquid water is converted to steam. The resulting scale forms an insulating layer, impeding the flow of heat through the equipment. As the thickness of the formed scale increases, the rate of steam generation decreases, as does the rate of heat flow. In addition, due to the accumulation of heat, the temperature of the metal surface may increase to the point where the metal surface itself may be damaged. Generally, drain valves are installed on equipment in processes where the working fluid is water. If the water contains solid impurities and some of the water continues to evaporate through some mechanism, such as drafting in a cooling tower or vaporization in a boiler, then the concentration of solid impurities in other water that accumulates in the equipment increases. Drain valves are used to drain a certain amount of liquid from equipment that contains solid impurities that by their nature are insoluble in the working fluid and may be deposited on the surface of the equipment, causing problems with the operation of the equipment.

If the water in the boiler is not well treated in the preparation stage, the density of insoluble substances (TDS) will increase due to steam generation. If the determined limit is exceeded, it can cause damage to the boiler and piping, and eventually lead to equipment failure. Insoluble materials are carried along with steam, and they can increase the conductivity of condensate and cause energy loss. Insoluble materials typically include calcium and magnesium salts, and these insoluble substances are deposited during the steam production process, and we need to remove them through a number of techniques to achieve optimum TDS levels. This operation is known as blowdown, and the valve used for this purpose is known as a blowdown valve.

Continuous blowdown: Also called surface blowdown, it is a continuous process of draining the most concentrated furnace water from the surface layer of the steam ladle furnace water. The purpose is to reduce the salinity and alkalinity of the boiler water to prevent the concentration of the furnace water from being too high and affecting the quality of steam. Continuous drain is generally installed in the steam ladle normal water level (i.e. “0” level) 80-100mm below. Furnace water is continuously evaporated and concentrated so that the highest concentration of salt is near the water surface. Therefore, the continuous drainage orifice should be installed in the area with the highest density of furnace water, in order to continuously discharge high-density furnace water and supplement it with clean feed water, so as to improve the quality of boiler water, and the drainage rate is generally about 1% of the evaporation volume.

The drain valve usually uses a gate valve or globe valve. The nominal diameter of the drain valve is DN25~50, rated evaporation ≥1t/h or working pressure ≥0.7Mpa boiler, the drain pipe should be installed with two drain valves in series.

The traditional design is a combination of 1 slow drain (with gate valve) + 1 fast drain (high-temperature ball valve), but due to the PTFE soft seal inside the ball valve, the valve seat is easily deformed by aging due to the long-term high temperature above 140℃, which eventually leads to valve leakage. And the gate valve sealing groove is easy to accumulate impurities, the gate does not close tightly and leaks. So this design service life is short.

Use one slow discharge (with bellows shut off globe valve S25FGB) + one fast discharge (quick-opening bellows shut-off valve S25F). The quick opening bellows globe valve S25FGB-1 is a special replacement for the high-temperature ball valve.

Advantages The switch is fast and convenient, only needs to make within 180 ℃ rotation, you can achieve from fully open to fully closed or fully closed to fully open, and the sealing performance of the globe valve, as well as the quick switching performance of the ball valve.

When discharging, the blowdown valve is subjected to high-temperature liquid flushing and dirt wear and will be cooled to room temperature after it stops draining. In order to improve the drain valve’s frequent poor working conditions such as pressure difference (large differential pressure drop), scale corrosion and wear vibration, and thermal shock,the series drain valve has a certain operation procedure: when discharging, valve 1 (slow opening blowdown valve) is opened first, then valve 2 (quick opening blowdown valve) is opened; when stopping discharging, valve 2 is closed first, then valve 1 is closed.

Valve 1 is a slow-opening blowdown valve, which should have the ability to resist alkaline corrosion of furnace water; valve 2 is a fast-opening blowdown valve, which should meet the action and time requirements of drainage.

THINKTANKis a reliableblowdown valve supplier, manufacturerand factory, with rich experience in replacing international brands for boiler manufacturers and end-users. If you have any related questions about blowdown valves, please feel free to contact us. We are here willing to provide expert service for you.

Custom manufacturer of cooling water, boiler water, closed loop & heating water system treatment chemicals, coil & duct cleaners, anitfoam defoaming agents & descale products. Meets ISO 9001 standards. Distributor of water treatment equipment & supplies including defoaming agents, alarms, antennas, dual head assemblies, automation systems, blocks, chemical & static in-line mixers, chlorinators, coil cleaners, calibration columns, flow controls, sample coolers, ultraviolet (UV) sterilizers, tubing, deodorizers, chemical bypass feeders, filters, flowmeters, gages, chemical injectors, water & pulse meters, misting systems, monitoring systems, pumps, racks, refractometers, rotameters, flow sensors, solids separators, lift stations, liquid flow switches, tanks, safety equipment, test kits, testing equipment, level transmitters, thermometer wells, wireless remote controls & wireless transmitters. Training & industrial & processed water treatment services are also available.

Blowdown Valves keep boilers clean. Blowdown valves are used to vent the impurities, sediment, and other solids that are present in boiler water. They are opened periodically to prevent buildup. They are also used to regulate the conductivity of the water in a boiler, because higher electrical conductivity causes scale to build up faster.

Blowdown valves come in two varieties, fast-open and slow-open. Fast-open valves act as the quick cutoff, while slow-open valves allow modulation of the water flow.

During a blowdown, the fast-open valve is opened first. This feeds the slow-open valve, which can then be opened gradually for operator safety and to prevent thermal shock to the drain pipes.

There are four locations where blowdown valves are typically installed:The bottom of the sight glassto keep water readings accurateThe bottom of the boilerto remove heavier solids, sediment, and impuritiesLevel with the surface of the water inside the boilerto allow floating impurities to be blown outThe low water cutoff, to confirm that it is operating properly

Without the blowdown valve in place, sediment and other impurities would gradually build up along the inside surface of the boiler. This would not only reduce the boiler’s operating efficiency, it could also become a safety hazard by creating uneven heating and metal stress.

Blowdown valves also regulate electrical conductivity in the boiler water by regulating the amount of suspended solids. Higher electrical conductivity creates faster scale buildup, which reduces a boiler’s operating efficiency. Higher conductivity also decreases the life of the boiler by accelerating the corrosive effects of the oxygen inside.

Things to Consider about Blowdown Valves:When the blowdown valve is opened, the water is extremely hot, and has a lot of steam pressure behind it. Always use extreme caution and be aware of your environment when operating a blowdown valve.Always wear proper protective equipment when operating a blowdown valve.Open the valve slowly. This is not only for operator safety, it also reduces thermal shock to the venting pipes.After completing a blowdown, momentarily crack the slow-open valve to release the pressure between the valves.

In order to ensure that the maximum allowable accumulation pressure of any system or apparatus protected by a safety valve is never exceeded, careful consideration of the safety valve’s position in the system has to be made. As there is such a wide range of applications, there is no absolute rule as to where the valve should be positioned and therefore, every application needs to be treated separately.

A common steam application for a safety valve is to protect process equipment supplied from a pressure reducing station. Two possible arrangements are shown in Figure 9.3.3.

The safety valve can be fitted within the pressure reducing station itself, that is, before the downstream stop valve, as in Figure 9.3.3 (a), or further downstream, nearer the apparatus as in Figure 9.3.3 (b). Fitting the safety valve before the downstream stop valve has the following advantages:

• The safety valve can be tested in-line by shutting down the downstream stop valve without the chance of downstream apparatus being over pressurised, should the safety valve fail under test.

• When setting the PRV under no-load conditions, the operation of the safety valve can be observed, as this condition is most likely to cause ‘simmer’. If this should occur, the PRV pressure can be adjusted to below the safety valve reseat pressure.

Indeed, a separate safety valve may have to be fitted on the inlet to each downstream piece of apparatus, when the PRV supplies several such pieces of apparatus.

• If supplying one piece of apparatus, which has a MAWP pressure less than the PRV supply pressure, the apparatus must be fitted with a safety valve, preferably close-coupled to its steam inlet connection.

• If a PRV is supplying more than one apparatus and the MAWP of any item is less than the PRV supply pressure, either the PRV station must be fitted with a safety valve set at the lowest possible MAWP of the connected apparatus, or each item of affected apparatus must be fitted with a safety valve.

• The safety valve must be located so that the pressure cannot accumulate in the apparatus viaanother route, for example, from a separate steam line or a bypass line.

It could be argued that every installation deserves special consideration when it comes to safety, but the following applications and situations are a little unusual and worth considering:

• Fire - Any pressure vessel should be protected from overpressure in the event of fire. Although a safety valve mounted for operational protection may also offer protection under fire conditions,such cases require special consideration, which is beyond the scope of this text.

• Exothermic applications - These must be fitted with a safety valve close-coupled to the apparatus steam inlet or the body direct. No alternative applies.

• Safety valves used as warning devices - Sometimes, safety valves are fitted to systems as warning devices. They are not required to relieve fault loads but to warn of pressures increasing above normal working pressures for operational reasons only. In these instances, safety valves are set at the warning pressure and only need to be of minimum size. If there is any danger of systems fitted with such a safety valve exceeding their maximum allowable working pressure, they must be protected by additional safety valves in the usual way.

In order to illustrate the importance of the positioning of a safety valve, consider an automatic pump trap (see Block 14) used to remove condensate from a heating vessel. The automatic pump trap (APT), incorporates a mechanical type pump, which uses the motive force of steam to pump the condensate through the return system. The position of the safety valve will depend on the MAWP of the APT and its required motive inlet pressure.

This arrangement is suitable if the pump-trap motive pressure is less than 1.6 bar g (safety valve set pressure of 2 bar g less 0.3 bar blowdown and a 0.1 bar shut-off margin). Since the MAWP of both the APT and the vessel are greater than the safety valve set pressure, a single safety valve would provide suitable protection for the system.

Here, two separate PRV stations are used each with its own safety valve. If the APT internals failed and steam at 4 bar g passed through the APT and into the vessel, safety valve ‘A’ would relieve this pressure and protect the vessel. Safety valve ‘B’ would not lift as the pressure in the APT is still acceptable and below its set pressure.

It should be noted that safety valve ‘A’ is positioned on the downstream side of the temperature control valve; this is done for both safety and operational reasons:

Operation - There is less chance of safety valve ‘A’ simmering during operation in this position,as the pressure is typically lower after the control valve than before it.

Also, note that if the MAWP of the pump-trap were greater than the pressure upstream of PRV ‘A’, it would be permissible to omit safety valve ‘B’ from the system, but safety valve ‘A’ must be sized to take into account the total fault flow through PRV ‘B’ as well as through PRV ‘A’.

A pharmaceutical factory has twelve jacketed pans on the same production floor, all rated with the same MAWP. Where would the safety valve be positioned?

One solution would be to install a safety valve on the inlet to each pan (Figure 9.3.6). In this instance, each safety valve would have to be sized to pass the entire load, in case the PRV failed open whilst the other eleven pans were shut down.

If additional apparatus with a lower MAWP than the pans (for example, a shell and tube heat exchanger) were to be included in the system, it would be necessary to fit an additional safety valve. This safety valve would be set to an appropriate lower set pressure and sized to pass the fault flow through the temperature control valve (see Figure 9.3.8).

As soon as mankind was able to boil water to create steam, the necessity of the safety device became evident. As long as 2000 years ago, the Chinese were using cauldrons with hinged lids to allow (relatively) safer production of steam. At the beginning of the 14th century, chemists used conical plugs and later, compressed springs to act as safety devices on pressurised vessels.

Early in the 19th century, boiler explosions on ships and locomotives frequently resulted from faulty safety devices, which led to the development of the first safety relief valves.

In 1848, Charles Retchie invented the accumulation chamber, which increases the compression surface within the safety valve allowing it to open rapidly within a narrow overpressure margin.

Today, most steam users are compelled by local health and safety regulations to ensure that their plant and processes incorporate safety devices and precautions, which ensure that dangerous conditions are prevented.

The principle type of device used to prevent overpressure in plant is the safety or safety relief valve. The safety valve operates by releasing a volume of fluid from within the plant when a predetermined maximum pressure is reached, thereby reducing the excess pressure in a safe manner. As the safety valve may be the only remaining device to prevent catastrophic failure under overpressure conditions, it is important that any such device is capable of operating at all times and under all possible conditions.

Safety valves should be installed wherever the maximum allowable working pressure (MAWP) of a system or pressure-containing vessel is likely to be exceeded. In steam systems, safety valves are typically used for boiler overpressure protection and other applications such as downstream of pressure reducing controls. Although their primary role is for safety, safety valves are also used in process operations to prevent product damage due to excess pressure. Pressure excess can be generated in a number of different situations, including:

The terms ‘safety valve’ and ‘safety relief valve’ are generic terms to describe many varieties of pressure relief devices that are designed to prevent excessive internal fluid pressure build-up. A wide range of different valves is available for many different applications and performance criteria.

In most national standards, specific definitions are given for the terms associated with safety and safety relief valves. There are several notable differences between the terminology used in the USA and Europe. One of the most important differences is that a valve referred to as a ‘safety valve’ in Europe is referred to as a ‘safety relief valve’ or ‘pressure relief valve’ in the USA. In addition, the term ‘safety valve’ in the USA generally refers specifically to the full-lift type of safety valve used in Europe.

Pressure relief valve- A spring-loaded pressure relief valve which is designed to open to relieve excess pressure and to reclose and prevent the further flow of fluid after normal conditions have been restored. It is characterised by a rapid-opening ‘pop’ action or by opening in a manner generally proportional to the increase in pressure over the opening pressure. It may be used for either compressible or incompressible fluids, depending on design, adjustment, or application.

Safety valves are primarily used with compressible gases and in particular for steam and air services. However, they can also be used for process type applications where they may be needed to protect the plant or to prevent spoilage of the product being processed.

Relief valve - A pressure relief device actuated by inlet static pressure having a gradual lift generally proportional to the increase in pressure over opening pressure.

Relief valves are commonly used in liquid systems, especially for lower capacities and thermal expansion duty. They can also be used on pumped systems as pressure overspill devices.

Safety relief valve - A pressure relief valve characterised by rapid opening or pop action, or by opening in proportion to the increase in pressure over the opening pressure, depending on the application, and which may be used either for liquid or compressible fluid.

In general, the safety relief valve will perform as a safety valve when used in a compressible gas system, but it will open in proportion to the overpressure when used in liquid systems, as would a relief valve.

Safety valve- A valve which automatically, without the assistance of any energy other than that of the fluid concerned, discharges a quantity of the fluid so as to prevent a predetermined safe pressure being exceeded, and which is designed to re-close and prevent further flow of fluid after normal pressure conditions of service have been restored.

A little product education can make you look super smart to customers, which usually means more orders for everything you sell. Here’s a few things to keep in mind about safety valves, so your customers will think you’re a genius.

A safety valve is required on anything that has pressure on it. It can be a boiler (high- or low-pressure), a compressor, heat exchanger, economizer, any pressure vessel, deaerator tank, sterilizer, after a reducing valve, etc.

There are four main types of safety valves: conventional, bellows, pilot-operated, and temperature and pressure. For this column, we will deal with conventional valves.

A safety valve is a simple but delicate device. It’s just two pieces of metal squeezed together by a spring. It is passive because it just sits there waiting for system pressure to rise. If everything else in the system works correctly, then the safety valve will never go off.

A safety valve is NOT 100% tight up to the set pressure. This is VERY important. A safety valve functions a little like a tea kettle. As the temperature rises in the kettle, it starts to hiss and spit when the water is almost at a boil. A safety valve functions the same way but with pressure not temperature. The set pressure must be at least 10% above the operating pressure or 5 psig, whichever is greater. So, if a system is operating at 25 psig, then the minimum set pressure of the safety valve would be 30 psig.

Most valve manufacturers prefer a 10 psig differential just so the customer has fewer problems. If a valve is positioned after a reducing valve, find out the max pressure that the equipment downstream can handle. If it can handle 40 psig, then set the valve at 40. If the customer is operating at 100 psig, then 110 would be the minimum. If the max pressure in this case is 150, then set it at 150. The equipment is still protected and they won’t have as many problems with the safety valve.

Here’s another reason the safety valve is set higher than the operating pressure: When it relieves, it needs room to shut off. This is called BLOWDOWN. In a steam and air valve there is at least one if not two adjusting rings to help control blowdown. They are adjusted to shut the valve off when the pressure subsides to 6% below the set pressure. There are variations to 6% but for our purposes it is good enough. So, if you operate a boiler at 100 psig and you set the safety valve at 105, it will probably leak. But if it didn’t, the blowdown would be set at 99, and the valve would never shut off because the operating pressure would be greater than the blowdown.

All safety valves that are on steam or air are required by code to have a test lever. It can be a plain open lever or a completely enclosed packed lever.

Safety valves are sized by flow rate not by pipe size. If a customer wants a 12″ safety valve, ask them the flow rate and the pressure setting. It will probably turn out that they need an 8×10 instead of a 12×16. Safety valves are not like gate valves. If you have a 12″ line, you put in a 12″ gate valve. If safety valves are sized too large, they will not function correctly. They will chatter and beat themselves to death.

Safety valves need to be selected for the worst possible scenario. If you are sizing a pressure reducing station that has 150 psig steam being reduced to 10 psig, you need a safety valve that is rated for 150 psig even though it is set at 15. You can’t put a 15 psig low-pressure boiler valve after the reducing valve because the body of the valve must to be able to handle the 150 psig of steam in case the reducing valve fails.

The seating surface in a safety valve is surprisingly small. In a 3×4 valve, the seating surface is 1/8″ wide and 5″ around. All it takes is one pop with a piece of debris going through and it can leak. Here’s an example: Folgers had a plant in downtown Kansas City that had a 6×8 DISCONTINUED Consolidated 1411Q set at 15 psig. The valve was probably 70 years old. We repaired it, but it leaked when plant maintenance put it back on. It was after a reducing valve, and I asked him if he played with the reducing valve and brought the pressure up to pop the safety valve. He said no, but I didn’t believe him. I told him the valve didn’t leak when it left our shop and to send it back.

If there is a problem with a safety valve, 99% of the time it is not the safety valve or the company that set it. There may be other reasons that the pressure is rising in the system before the safety valve. Some ethanol plants have a problem on starting up their boilers. The valves are set at 150 and they operate at 120 but at startup the pressure gets away from them and there is a spike, which creates enough pressure to cause a leak until things get under control.

If your customer is complaining that the valve is leaking, ask questions before a replacement is sent out. What is the operating pressure below the safety valve? If it is too close to the set pressure then they have to lower their operating pressure or raise the set pressure on the safety valve.

Is the valve installed in a vertical position? If it is on a 45-degree angle, horizontal, or upside down then it needs to be corrected. I have heard of two valves that were upside down in my 47 years. One was on a steam tractor and the other one was on a high-pressure compressor station in the New Mexico desert. He bought a 1/4″ valve set at 5,000 psig. On the outlet side, he left the end cap in the outlet and put a pin hole in it so he could hear if it was leaking or not. He hit the switch and when it got up to 3,500 psig the end cap came flying out like a missile past his nose. I told him to turn that sucker in the right direction and he shouldn’t have any problems. I never heard from him so I guess it worked.

If the set pressure is correct, and the valve is vertical, ask if the outlet piping is supported by something other than the safety valve. If they don’t have pipe hangers or a wall or something to keep the stress off the safety valve, it will leak.

There was a plant in Springfield, Mo. that couldn’t start up because a 2″ valve was leaking on a tank. It was set at 750 psig, and the factory replaced it 5 times. We are not going to replace any valves until certain questions are answered. I was called to solve the problem. The operating pressure was 450 so that wasn’t the problem. It was in a vertical position so we moved on to the piping. You could tell the guy was on his cell phone when I asked if there was any piping on the outlet. He said while looking at the installation that he had a 2″ line coming out into a 2×3 connection going up a story into a 3×4 connection and going up another story. I asked him if there was any support for this mess, and he hung up the phone. He didn’t say thank you, goodbye, or send me a Christmas present.

“4Matic” Blowdown valves are used to drain some amount of liquid from an equipment. It is attached to those equipment whose working fluids contain solid impurities. The nature of such impurities are that they don’t dissolve in the working fluid and it may get deposited on the surfaces of the equipment this causing problems in the operation of the equipment.

A spring-loaded relief valve can be thought of as a spring /mass system which is why relief valves chatter. Researchers have found significant differences in the stability of relief valves based on the design of their internals. One recent study found that with 6 feet of inlet piping, valves from Manufacturer X were stable in 50% of the tests while valves from Manufacturer Z where stable in 100% of these tests.¹ Smith & Burgess Laboratory research has confirmed these findings. However, relief systems designers tend to downplay (if not ignore) the importance of the mechanical design of relief valves which is important to stability. Therefore, this article discusses the fundamentals of the design parameters for the internals of a relief valve. The intent is to provide design considerations and general operation information for use by relief systems designers, specifically assisting with the understanding of the effects of valve design on stability.

Modern relief valves are wonderfully modular.The internal parts for a relief valve (valve disc,disc holder, blowdown ringandspring) can be interchanged for ones with a different design to customize valve performance based on the application, fluid service, and set pressure.Valve disccan be metal-to-metal or soft seats. Soft seat designs use an elastomer to create a better seal between thevalvediscand thenozzle. Relief valves with elastomer seats have limitations and can only be used in certain applications.Disc holdersare generally designed to allow thevalve discto float which provides an angular movement that reduces seat leakage from minor misalignments (ensuring that thevalve dischas 360 degrees of contact with thenozzle). Thedisc holderoutside diameter, shape and thickness plays an important role in determining the valve performance by defining the shape of thehuddling chamber. Thehuddling chambercan also be defined by theblowdown ring(s). Thering(s)can also be swapped to different sized and shapedringsto adjust performance based on the expected relief fluid.Springsare selected to keep the valve closed and must fit inside thevalve bonnet. The force thespringexerts is an important design criteria for a relief device and varies depending on the relief fluid, valve size and set pressure.

Spring loaded relief valves are known as "pop action" relief valves as they typically pop open at their set pressure. Initially, the pressure differential across thevalve discthat creates the force to over come the spring force and open the valve.The pop action occurs because mosthuddling chambersare designed with an area that is approximately 10%-30% larger than thevalve seat(as thedisc holderis bigger than thevalve disc). Once the pressure under the seat is enough to lift thevalve discoff thenozzle, there is a step change in the upward forces on thespringand the valve "pops" open. The shape of thehuddling chamber(created by the shape and size of thedisc holder), the position and shape of theblowdown ring, and the characteristics of the fluid being relieved together determine the initial opening force and the initial lift of the valve.

Blowdown ringsare adjustable rings with a design shape that modifies the effluent flow path andhuddling chamberbased on the position. For process valves, a singleblowdown ringis typically threaded onto thenozzleand can be adjusted vertically up or down. Manufacturers will specify a recommended position relative to contact with thevalve disc. The position of theblowdown ringis fixed with a locking screw. The position of theblowdown ringchanges the blowdown (or reseat) pressure. For valves with a singleblowdown ring, the closer theblowdown ringis to thenozzle, the lower the pressure in the system will need to be for the valve to close (more blowdown). Other relief valves have multipleblowdown rings. Each manufacturer designs a uniqueblowdown ringto compliment other aspects of the relief valve design. Smith & Burgess" testing confirms that position and design ofblowdown ring(s)affects valve stability.

Relief Valve manufactures generally select aspringthat is designed for the set pressure of the valve. Thespringthat is selected will have a pressure range that thespringcan be applied. In many cases, there may be more than onespringthat can be used with each relief valve each having a different spring constant. The stifferspringmay have a range that is higher than the softerspringbut still meet the overall requirements for set pressure. The selection of thespringwill affect stability as the specific spring influences the natural frequency of the valve and can also affect the blowdown.

Manufacturer of a wide range of products which include boiler safety valve, safety valve-pop type, pressure safety valve, spring loaded safety valve, safety relief valve and ibr safety valve.

ConnectionThreaded and Flanged EndsWe are the manufacturer, Supplier, and Exporter of Boiler Safety Valve from Chennai -India to Globally. These Safety Valves are Used to release the excess pressure inside the Boiler, High-Pressure Tanks, nd Vessels. So that Pressure can be maintained uniformly. we are manufacturer of valves like: Pressure Relief Valves, Safety relief Valves, Vacuum Relief Valve, Pressure cum vacuum relief valve, Breather valves.

Certificate-ApprovalISO, IBR, IRS, ATEX, TUV, BV, SGSWe are the manufacturer, supplier, and exporter of Safety Valves from Chennai-India to Globally. Used for controlling excess pressures, their precision construction standards make them extensively used in equipment like pressure vessels, pipelines & reactors.We have good infrastructure facility for EXPORT

LeverPlain and Packed LeverBEEKAY brand Safety Valve, Safety Relief Valve, pressure Safety Valves are manufactured by LEVEL AND FLOW CONTROL ENGINEERS in India. Pressure Safety Valve can safeguard the tanks, vessels, boilers, and other capital equipments. when the pressure is esceed the limit valve will open automatically and release the excess pressure.we are expecting enquiry and orders from all over the world.

Accumulation0 to 10%LFCE Spring Loaded Safety Valve, Safety Relief Valves and Pressure Relief Valves are high performance and cost effective. Based on client request we can ready to supply valves with 0 to 5% accumulation and blowdown.Valve size : 1/4" to 12"

Country of OrginIndiaBEEKAY brand Safety Valve, Safety Relief Valve are manufactured by Level and Flow Control Engineers in INDIA. Valves are 100% safe and accuracy for Set pressure and Re-set pressures. Valves are mounted on pipelines, tanks, vessels and reactors to safeguard the capital equipments.We have already exported our range of products to all over the world like UAE, Middle East, Germany, Italay, Australlia, Malysia, Thailand, Indonesia, Philipines, Burunei, Srilanka, Pakistan, Netherland and many more

Flange Ratings150, 300, 600, 900, 1500 lbs RatingsLFCE Manufacturing, supplying, Exporting IBR Certified Safety Valves for Boilers, Deareators, LP, HP Heaters, Condensate Tanks and Vessels. We can able to supply the valves size from 25NB to 300NB and the Pressure Rating 150 lbs to 1500 lbs

We are expecting enquiry and orders from all over the world. Our valves and range of products are well exported to UAE, MIddle East, Thailand, Indonesia, Mayanmar, Vietnam, Srilanka, Malaysia, Singapore, Philipines, Australlia, Netherland, Italy, UAE, South African Countires.

Country of OriginMade in IndiaLFCE manufacturing, supplying, EXPORTING Safety Valve, Pressure Relief Valves with Lever and Plain types.We can able to supply CS, SS, DSS, SDSS, Alloy Steel grade of Materials with Max. of Pressure of 150 barValve size from 15NB to 200NBWe are expecting good enquiry and orders from all over the globe.

Rust ResistanceYesLFCE manufacturing and supplying Beekay brand Brass Safety Valves, Safety Relief Valves, Pressure Relief Valves fo the pressure vessels and Air Receivers. When the pressure is exceed the limit then the valve will open automatically and safeguard the capital equipments.Our brand Beekay is well known in the global market. Already we exported our range of products to all over the world :- UAE, Middle East, South Africa, Zimbawe, Zambia, Kenya, Oman, Saudi Arabia, Thailand, Indonesia, Philipines, Burunei, Srilanka, Pakistan, Hongkong, Netherland, Italay and many more

Flange StandardsANSI, BS, DIN, JS, IS, ASMELFCE manufacturing and EXPORTING Low Pressure, Medium Pressure, High Pressure Safety Valves, Safety Relief Valves for the Process Industries and Hydro Carbon Projects.Our Valves are manufactured and tested as per API StandardsWe are expecting enquiry/orders from all over the world.

PG-71.7 Every boiler shall have proper outlet connections for the required pressure relief valve, or valves, independent of any other outside steam connection,. the area of opening to be at least equal to the aggregate areas of inlet connections of all of the pressure relief valves to be attached thereto. An internal collecting pipe, splash plate, or pan may be used, provided the total area for inlet of steam thereto is not less than twice the aggregate areas of the inlet connections of the attached pressure relief valves. The holes in such collecting pipes shall be at least ¼ in. (6 mm) in diameter and the least dimension in any other form of opening for inlet of steam shall be ¼ in. (6 mm).

Such dimensional limitations to operation for steam need not apply to steam scrubbers or driers provided the net free steam inlet area of the scrubber or drier is at least 10 times the total area of the boiler outlets for the pressure relief valves.

PG-71.8 If pressure relief valves are attached to a separate steam drum or dome, the opening between the boiler proper and the steam drum or dome shall be not less than required by PG-71.7.

PG-72.1 Pressure relief valves shall be designed and constructed to operate without chattering, with a minimum blowdown of 2 psi (15 kPa) or 2% of the set pressure, whichever is greater, and to attain full lift at a pressure not greater than 3% above their set pressure.

Pressure relief valves used on forced-flow steam generators with no fixed steam and waterline, and pressure relief valves used on high-temperature water boilers must be marked for these special services by the valve Manufacturer or Assembler.

PG-72.3 The spring in a pressure relief valve shall not be reset for any pressure more than 5% above or below that for which the valve is marked unless the new setting is within the spring design range established by the manufacturer or is determined to be acceptable to the manufacturer.

If the set pressure is to be adjusted within the limits specified above, the adjustment shall be performed by the manufacturer, his authorized representative, or an assembler. An additional valve data tag identifying the new set pressure, capacity, and date shall be furnished and installed, and the valve shall be resealed.

PG-72.4 If the set pressure of a valve is changed so as to require a new spring, the spring shall be acceptable to the manufacturer. The spring installation and valve adjustment shall be performed by the manufacturer, his authorized representative, or an assembler. A new nameplate as described in PG-110 shall be furnished and installed, and the valve shall be resealed.

PG-73.1.1 Pressure relief valves shall be either direct spring-loaded safety valves, direct spring-loaded safety relief valves, or pilot-operated pressure relief valves.

PG-73.2.1 All pressure relief valves shall be so constructed that the failure of any part cannot obstruct the free and full discharge of steam and water from the valve. Pressure relief valves shall have the seat inclined at any angle between 45 deg and 90 deg, inclusive, to the centerline of the disk.

PG-73.2.4 To provide a means for verifying whether it is free, each safety valve or safety relief valve shall have a substantial lifting device, which when activated will release the seating force on the disk when the valve is subjected to pressure of at least 75% of the set pressure. The lifting device shall be such that it cannot lock or hold the valve disk in lifted position when the exterior lifting force is released. Disks of pressure relief valves used on high-temperature water boilers shall not be lifted while the temperature of the water exceeds 200°F (93°C). If it is desired to lift the valve disk to assure that it is free, this shall be done when the valve is subjected to a pressure of at least 75% of the set pressure. Pilot-operated pressure relief valves shall be provided with either a lifting device as described above or means for connecting and applying pressure to the pilot adequate to verify that the moving parts critical to proper operations are free to move. For high-temperature water boilers, the lifting mechanism shall be sealed against leakage.

PG-73.2.5 The seat of a pressure relief valve shall be fastened to the body of the valve in such a way that there is no possibility of the seat lifting.

PG-73.2.6 A body drain below seat level shall be provided in the valve and this drain shall not be plugged during or after field installation. For valves exceeding NPS 2 ½ (DN 65), the drain hole or holes shall be tapped not less than NPS 3/8 (DN 10). For valves of NPS 2 ½ (DN 65) or smaller, the drain hole shall not be less than ¼ in. (6 mm) in diameter.

PG-73.2.8 Valves having screwed inlet or outlet connections shall be provided with wrenching surfaces to allow for normal installation without damaging operating parts.

PG-73.2.9 Means shall be provided in the design of all valves for use under this Section, for sealing all external adjustments. Seals shall be installed by the manufacturer, his authorized representative, or an assembler at the time of the initial adjustment. After spring replacement and/or subsequent adjustment, the valve shall be resealed. Seals shall be installed in such a manner as to prevent changing the adjustment without breaking the seal and, in addition, shall serve as a means of identifying the manufacturer, his authorized representative, or the assembler making the adjustment.

(c) The restriction of valve capacity shall be permitted only by the use of a lift restraining device which shall limit valve lift and shall not otherwise interfere with flow through the valve. The design of the lift restraining device shall be subject to review by an ASME designee.

(d) The lift restraining device shall be designed so that, if adjustable, the adjustable feature can be sealed. Seals shall be installed by the valve Manufacturer or Assembler at the time of initial adjustment.

(f) When sizing and selecting valves, the restricted lift nameplate capacity shall be determined by multiplying the capacity at full rated lift by the ratio of the restricted lift to the full rated lift.

PG-73.2.11 A pressure relief valve over NPS 3 (DN 80), used for pressure greater than 15 psig (100 kPa), shall have a flanged inlet connection or a welded inlet connection. The dimensions of the flanges subjected to boiler pressure shall conform to the applicable ASME standards as given in PG-42. The facing shall be similar to those illustrated in the standard.

PG-73.3.2 Adjacent sliding surfaces such as guides and disks or disk holders shall both be of corrosion-resistant material. Springs of corrosion-resistant material or having a corrosion-resistant coating are required. The seats and disks of pressure relief valves shall be of suitable material to resist corrosion by the lading fluid.

(c) controlled by the manufacturer of the pressure relief valve by a specification ensuring control of chemical and physical properties and quality at least equivalent to ASTM Standards (see Note below)

PG-73.3.4 Pressure relief valves may have bronze parts complying with either SB-61, SB-62 or SB-148, provided the maximum allowable stresses and temperatures do not exceed the values given in Table 1B of Section II, Part D, and shall be marked to indicate the class of material used. Such valves shall not be used on superheaters delivering steam at a temperature over 450°F (230°C) for SB-61 and SB-148, and 306°F (I50°C) for SB-62, and shall not be used for high-temperature water boilers.

PG-73.4.1 A manufacturer shall demonstrate to the satisfaction of an ASME designee that his manufacturing, production, and test facilities and quality control procedures will ensure close agreement between the performance of random production samples and the performance of those valves submitted for capacity certification.

PG-73.4.3 A Manufacturer or Assembler may be granted permission to apply the V Code Symbol to production pressure relief valves capacity-certified in accordance with PG-69, provided the following tests are successfully completed. This permission shall expire on the sixth anniversary of the date it is initially granted. This permission may be extended for 6-yr periods if the following tests are successfully repeated within the 6-mo period before expiration.

(a) Two sample production pressure relief valves of a size and capacity within the capability of an ASME accepted laboratory shall be selected by an ASME designee. The maximum blowdown for these samples shall not exceed the value specified in the following table:

The blow down for sample valves designed for use on forced flow steam generators with no fixed steam and waterline or high-temperature water boilers shall not exceed 10% of the set pressure.

(b) Operational and capacity tests shall be conducted in the presence of an ASME designee at an ASME-accepted laboratory. The valve manufacturer or assembler shall be notified of the time of the test and may have representatives present to witness the test.

(c) Should any valve fail to relieve at or above its certified capacity or should it fail to meet performance requirements in PG-72, the test shall be repeated at the rate of two replacement valves, selected in accordance with PG-73.4.3(a), for each valve that failed.

(d) Failure of any of the replacement valves to meet capacity or the performance requirements of this Section shall be cause for revocation within 60 days of the authorization to use the Code symbol on that particular t type of valve. During this period, the Manufacturer or assembler shall demonstrate the cause of such deficiency and the action taken toward against future occurrence.

PG-73.4.4 Use of the Code Symbol Stamp by an assembler indicates the use of original unmodified parts in strict accordance with the instructions of the manufacturer of the valve.

(2) the Quality Control System of the Assembler receiving the pressure relief valve parts shall define the controls for the procurement and acceptance of those parts

(b) However, an assembler may convert original finished parts by either machining to another finished part or applying a corrosion-resistant coating to valve springs for a specific application under the following conditions:

(5) For an Assembler to offer restricted lift valves, the Assembler must demonstrate to the satisfaction of the Manufacturer the ability to perform valve lift restrictions. The Manufacturer shall document all authorizations granted to restrict the lift of the valves, and shall maintain records of the lift restrictions made by the Assembler. The Assembler shall maintain a file of such authorizations.

NOTES: Within the requirements of PG-73.4 and PG-73.5, a manufacturer is defined as a person or organization who is completely responsible for design, material selection, capacity certification, manufacture of all component parts, assembly, testing, sealing, and shipping of pressure relief valves certified under this Section.

Anassembleris defined as a person or organization who purchases or receives from a manufacturer the necessary component parts or valves and assembles, adjusts, tests, seals, and ships pressure relief valves certified under this Section at a geographical location other than and using facilities other than those used by the manufacturer.

PG-73.5.1 Pressure Testing. Each pressure relief valve to which the Code Symbol Stamp is to be applied shall be subjected to the following tests by the Manufacturer or Assembler:

(a) The pressure-containing parts of each valve shall be hydrostatically tested at a pressure at least 1.5 times the design pressure of the parts. Parts meeting the following criteria shall be exempt from pressure testing:

(d) When the valve is designed for discharging directly to atmosphere, the valve components downstream of the valve disk are exempt from pressure testing.

PG-73.5.2 Every valve shall be tested with steam by the manufacturer or assembler to demonstrate its set point and pressure-containing integrity. The blowdown control elements of the pressure relief valve shall be set to the Manufacturer"s specifications.

PG-73.5.2.2 When the valve is beyond the production test equipment capabilities, an alternative test method presented in PG-73.5.2.2.1 or PG-73.5.2.2.2 may be used, provided all of the following conditions are met:

(a) testing the valve at full pressure may cause damage to the valve, or testing of the valve is impractical due to boiler system operational safety considerations

(c) O-rings or other packing devices when used on the stems of safety relief valves shall be so arranged as not to affect their operation or capacity.

(d) The design shall incorporate guiding arrangements necessary to insure consistent operation and tightness. Excessive lengths of guiding surfaces should be avoided. Bottom guided designs are not permitted on safety relief valves.

(f) Safety valves shall be spring loaded. The spring shall be designed so that the full lift spring compression shall be no greater than 80% of the nominal solid deflection. The permanent set of the spring (defined as the difference between the free height and height measured 10 min after the spring has been compressed solid three additional times after presetting at room temperature) shall not exceed 0.5% of the free height.

(h) A body drain below seat level shall be provided by the Manufacturer for all safety valves and safety relief valves, except that the body drain may be omitted when the valve seat is above the bottom of the inside diameter of the discharge piping. For valves exceeding NPS 2½ (DN 65) the drain hole or holes shall be tapped not less than NPS 3/8 (DN 10). For valves NPS 2½ (DN 65) or smaller, the drain hole shall not be less than ¼ in. (6 mm) in diameter. Body drain connections shall not be plugged during or after field installation. In safety relief valves of the diaphragm type, the space above the diaphragm shall be vented to prevent a buildup of pressure above the diaphragm. Safety relief valves of the diaphragm type shall be so designed that failure or deterioration of the diaphragm material will not impair the ability of the valve to relieve at the rated capacity.

(k) The set pressure tolerances, plus or minus, of safety valves shall not exceed 2 psi (15 kPa), and for safety relief valves shall not exceed 3 psi (20 kPa) for pressures up to and including 60 psig (400 kPa) and 5% for pressures above 60 psig (400 kPa).

(l) Safety valves shall be arranged so that they cannot be reset to relieve at a higher pressure than the maximum allowable working pressure of the boiler.

(e) Material for valve bodies and bonnets or their corresponding metallic pressure containing parts shall be listed in Section II,except that in cases where a manufacturer desires to make use of materials other than those listed in Section II, he shall establish and maintain specifications requiring equivalent control of chemical and physical properties and quality.

(a) A Manufacturer shall demonstrate to the satisfaction of an ASME designee that his manufacturing, production, and testing facilities and quality control procedures will insure close agreement between the performance of random production samples and the performance of those valves submitted for capacity certification.

(c) A Manufacturer may be granted permission to apply, the HV Code Symbol to production pressure relief valves capacity certified in accordance with HG-402.3 provided the following tests are successfully completed. This permission shall expire on the sixth anniversary of the date it is initially granted. The permission may be extended for 6 year periods if the following tests are successfully repeated within the 6 month period before expiration.

(1) Two sample production pressure relief valves of a size and capacity within the capability of an ASME accepted laboratory shall be selected by an ASME designee.

(2) Operational and capacity tests shall be conducted in the presence of an ASME designee at an ASME accepted laboratory. The valve Manufacturer shall be notified of the time of the test and may have representatives present to witness the test.

(3) Should any valve fail to relieve at or above its certified capacity or should it fail to meet performance requirements of this Section, the test shall be repeated at the rate of two replacement valves, selected in accordance with HG-401.3(c)(1), for each valve that failed.

(4) Failure of any of the replacement valves to meet the capacity or the performance requirements of this Section shall be cause for revocation within 60 days of the authorization to use the Code Symbol on that particular type of valve. During this period, the Manufacturer shall demonstrate the cause of such deficiency and the action taken to guard against future occurrence, and the requirements of HG-401.3(c) above shall apply.

(d) Safety valves shall be sealed in a manner to prevent the valve from being taken apart without breaking the seal. Safety relief valves shall be set and sealed so that they cannot be reset without breaking the seal.

(a) Every safety valve shall be tested to demonstrate its popping point, blowdown, and tightness. Every safety relief valve shall be tested to demonstrate its opening point and tightness. Safety valves shall be tested on steam or air and safety relief valves on water, steam, or air. When the blowdown is nonadjustable, the blowdown test may be performed on a sampling basis.

(c) Testing time on safety valves shall be sufficient, depending on size and design, to insure that test results are repeatable and representative of field performance.

HG-401.5 Design Requirements. At the time of the submission of valves for capacity certification, or testing in accordance with this Section, the ASME Designee has the authority to review the design for conformity with the requirements of this Section, and to reject or require modification of designs that do not conform, prior to capacity testing.

HG-402.1 Valve Markings. Each safety or safety-relief valve shall be plainly marked with the required data by the Manufacturer in such a way that the markings will not be obliterated in service. The markings shall be stamped, etched, impressed, or cast on the valve or on a nameplate, which shall be securely fastened to the valve.

(6) year built or, alternatively, a coding may be marked on the valves such that the valve Manufacturer can identify the year the valve was assembled and tested, and

HG-402.2 Authorization to Use ASME Stamp.Each safety valve to which the Code Symbol (Fig. HG-402) is to be applied shall be produced by a Manufacturer and/or Assembler who is in possession of a valid Certificate of Authorization. (See HG-540.) For all valves to be stamped with the HV Symbol, a Certified Individual (CI) shall provide oversight to ensure that the use of the “HV" Code symbol on a safety valve or safety relief valve is in accordance with this Section and that the use of the “HV" Code symbol is documented on a Certificate of Conformance Form, HV-1.

HG-402.3 Determination of Capacity to Be Stamped on Valves. The Manufacturer of the valves that are to be stamped with the Code symbol shall submit valves for testing to a place where adequate equipment and personnel are available to conduct pressure and relieving-capacity tests which shall be made in the presence of and certified by an authorized observer. The place, personnel, and authorized observer shall be approved by the Boiler and Pressure Vessel Committee. The valves shall be tested in one of the following three methods.

(a) Coefficient Method. Tests shall be made to determine the lift, popping, and blowdown pressures, and the capacity of at least three valves each of three representative sizes (a total of nine valves). Each valve of a given size shall be set at a different pressure. However, safety valves for steam boilers shall have all nine valves set at 15 psig (100 kPa). A coefficient shall be established for each test as follows: