spirax sarco safety valve made in china

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.

Spirax Sarco Thermodynamic Steam Trap are available with balanced-pressure bellows or wafer-type elements, which are constructed in a variety of materials in both stainless steel and carbon steel. These traps are used on applications with very light condensate loads.

A high capacity stainless steel full-lift clean service safety valve designed to AD Merkblatt A2 and TRD 421 standards and suitable for pure steam, vapor and inert gases.

Safety valves English safety valve is an industrial valve product, whose main function is to protect the pipeline from pressure surge beyond the rated value. During work, it is always in the closed state. When the inlet pressure exceeds the rated value, the valve opens to allow some liquid to flow through and recirculate to the container. The safety valve operates on the Bernoulli principle.

Safety valve and pressure relief valve are two types of valves with completely different features, but some people still confuse these two types of valves, so to compare the differences between them, people can follow the table below. down here.

Valve shaft: Connected to the valve disc, is a straight shaft made from high-strength materials, the main function of which is to support the opening and closing of the valve disc.

Valve body: Has a structure of an inlet and an outlet port connected to the main pipe, which is a pressure reducing pipe and an exhaust pipe to let the fluid flow to the tank. Valve body is usually made from materials such as stainless steel, copper, cast iron, steel ...

Spring: Using the elastic force of the spring to adjust the valve to open and close for pressure relief, the spring can change the compression through an adjustment screw.

Valve cover: Connected to the valve body by bolts, making the valve tight and easy to maintain, this cover is usually made of the same material as the valve body.

Adjustment screw: The adjusting screw is a part used to adjust the set pressure for the safety valve, it will directly adjust the compression of the spring.

When the pressure passing through the pipe exceeds the rated pressure to which this safety valve is preset, the pressure level of this flow exceeds the compression force of the spring. The piston will be pushed up, the safety valve is opened to discharge the fluid, excess pressure to the outside or be connected to the pipe connecting the tank to discharge to the tank. This helps to reduce the pressure.

When the pressure level in the pipeline returns to normal, the piston is pushed back to the original position, the safety valve will close completely.

Valve body: The valve body is usually made up of materials such as cast iron, copper, stainless steel, steel, etc. This valve body also has two installation ports, the inlet and outlet ports.

Auxiliary valve spring: The spring of the auxiliary valve is designed with great rigidity, which is the main part of this safety valve to adjust the set pressure of the safety valve.

Main valve spring: The spring of the main valve has a design with less stiffness than the spring of the auxiliary valve. The spring of the main valve is connected together with the piston.

Piston: A detail that closes and opens the valve"s outlet, through this part, the fluid can be discharged when overpressure or blocked when the pressure returns to normal pressure.

When the pressure in the system is below the set rating. Both the auxiliary valve and the main valve of the safety valve will be in the closed state. The higher the pressure, the greater the pressure in the upper chamber of the piston, the tighter the piston is closed (under pressure conditions below rated pressure).

When the pressure is above the rated pressure, the auxiliary valve opens, releasing the pressure in the chamber above the piston. At this time, the pressure under the piston is greater than the pressure above the piston, so the piston is pushed up, releasing the pressure in the system through the exhaust port.

When the pressure in the system returns to the pressure level below the rated pressure, the auxiliary valve closes and the main valve closes, the cycle repeats the same.

These safety valve products are mainly because of their compact, simpler design, which helps to reduce structural materials, so the cost will also be lower than indirect-acting safety valve products.

Designed with an extra valve to adjust the valve, these safety valves have a more moderate pressure release, are easier to adjust, have multiple pressure settings, and can set the rated pressure to a high level. than.

These full valves often have a more complicated structure, more details and more parts, which often makes it more difficult to maintain, service and repair the valve if the valve fails.

These indirect-acting safety valves are more suitable for clean, treated fluid applications, their auxiliary valves are often quite sensitive to dirt and are prone to clogging.

Designed with threaded connection. This type of valve is usually produced with a smaller size, with the characteristics of being compact and simple. For quick and convenient installation.

Designed with a recoil arm, which is directly linked to the valve shaft. This product will help to release pressure directly manually in case of emergency.

In the field of oil and gas, oil and gas industry, valves are used with the main purpose to discharge toxic substances to help prevent fire and explosion.

Currently, safety valves have a very diverse design, so choosing the right product for certain applications is not difficult. So, here are some tips to keep in mind:

Next, it is necessary to consider what type of system the application is (steam, gas or liquid systems). Because these fluids will have their own characteristics and valves will also have separate designs.

For example: In compressed air applications where the gas can be discharged directly to the environment, a valve with an open bonnet can be selected. For applications where liquid is discharged to the tank, or gaseous fluids are not allowed to be discharged into the environment, it is necessary to use a valve with a tight bonnet.

The structure of the valve is a factor to consider in the selection process. Valves with different structures have different characteristics and applications.

Performance is a factor to consider, valve performance requirements will vary from application to application which is why it is important to choose the right valve.

Standard requirements, safety valve standards are often concerned, because it is related to structure and performance. This standard is generally approved by independent bodies.

After determining the set pressure of the valve, we proceed to set the set pressure through the adjustment part which is the adjusting screw on the valve body.

It is necessary to flush the pipeline before installation, to avoid the accumulation of impurities and dirt that are the factors that cause damage to the details in the valve.

These valves need to be installed according to their installation standards, with different connection types the installation standards of these types will be different.

Leaks are often caused by a number of reasons such as: incorrect installation, faulty gaskets in the valve, making the valve unable to close properly. The condition of impurities and dirt mixed in the fluid can cause blockage, causing the valve to not close properly.

Failure to close or open error. The reason is that valves have discs stuck in the open position, unable to close, which causes fluid loss. Valves that do not open are discs stuck in the closed position, causing the valve to not work, which prevents the system from releasing excess pressure and endangers the system.

To prolong the life of the valve, the best way is to maintain and maintain the valve regularly and properly. Recommended maintenance period is at least once every 12 months.

1) It is a kind of pilot operated pressure reducing valve; 2) Especially be suitable for steam, and for water also; 3) Max. inlet pressure: 16 bar, 25 bar 4) Outlet pressure (Springs Pressure setting range): Yellow: 0.2 to 3 Bar Blue: 2.5 to 7 bar Red: 6 to 12 bar 5) Diameter: 15 - 200mm 6) Medium temperature: 0 ~ 285°C 7) Max. inlet to outlet pressure: 20:1 8) Body material: cast steel (WCB) Item 15 20 25 32 40 50 65 80 100 125 150 200 Parts Material Resistance pressure (MPa) 2.5 Shell test pressure (MPa) 3.75 Body WCB Seal test pressure (MPa) 2.5 Cover WCB Max.