fuel tank safety valve free sample

This invention relates generally to safety valves for fuel tanks and more particularly to such a safety valve capable of venting fluids under normal conditions of temperature change, preventing liquid fuel splashes from exiting the fuel tank during rough riding and for preventing fuel leakage should the fuel tank become inverted.

For gasoline and diesel fuel powered vehicles, gas tanks are mounted and contain a supply of such fuels. The fuel in gasoline tanks is always contained as both a liquid portion and its vapor phase portion. As ambient air temperature changes, and especially when a fuel tank is heated by incident sunlight, the vapor phase pressure within the tank will rise, and as this occurs, fuel vapor must be released from the tank or the pressure within the tank will quickly reach an unsafe level. Therefore, fuel tank caps have been produced in the prior art to enable fuel vapors to escape from fuel tanks. Such vapor phase outlets, however, present a problem as liquid fuel also tends to exit the fuel tank through the vapor outlet channel, and this causes a fire hazard condition to develop. Furthermore, liquid gasoline and similar fuels are considered to be a health risk and to contaminate the environment. Especially for gasoline fuel tanks on vehicles such as motorcycles and all-terrain vehicles, there is a significant problem with liquid fuel spilling from the fuel tank through outlets designed for vapor phase release. Furthermore, when a motorcycle or similar vehicle falls over or is inverted by accident or for maintenance work, liquid fuel can escape rapidly through vapor release passages. The following abstracts define the present state of this field in contending with these problems.

Gerdes, U.S. Pat. No. 4,036,399: A gas tank cap has an inner part connectable to a gas tank filler pipe and an outer part biased outwardly away from the inner part by a spring and normally freely rotatable relative to the inner part. One or more passages in the cap communicate with the filler pipe and with the ambient atmosphere and have valves interposed in them which are so positioned that when the outer part is pushed towards the inner part the valves are automatically opened to vent pressure from the gas tank. Only after the valves have opened in response to pushing of the outer part towards the inner part do the two parts become coupled for subsequent joint rotation so as to permit removal of the gas cap from the filler pipe.

Crute, U.S. Pat. No. 4,162,021: A pressure-vacuum cap for a chamber such as an automobile gas tank having a normally upwardly extending filler neck formed with a peripherally and radially extending, upwardly facing sealing surface concentric with the longitudinal axis of the neck, the cap comprising a cover, a concentric housing extending downwardly from the cover into the filler neck and a gasket or gaskets providing a seal between the housing and the sealing surface, the housing providing a valve body having a centrally disposed, concentric passageway extending axially therethrough and in communication with the chamber. A pressure-vacuum valve assembly is disposed in that passageway for normalizing the pressure in the chamber, venting the chamber to atmosphere when the pressure in the chamber exceeds a predetermined superatmospheric level and when the pressure in the chamber drops below a predetermined subatmospheric level. The cap also provides, in addition to the pressure-vacuum valve assembly, a roll-over valve assembly. Particularly, a rubber-like insert is disposed in the passageway to provide a downwardly facing, generally conical valve seat, and a ball is disposed in the passageway to move against the valve seat to close the passageway against movement of fluid from the chamber when the filler neck is tilted downwardly to a predetermined angle relative to a horizontal plane. The rubber-like insert also provides a seal against the pressure-vacuum valve assembly.

Harris, U.S. Pat. No. 4,685,584: A fuel cap for closing the filler neck of an off-road vehicle. The fuel cap includes a cover having an opening therethrough and a concentric housing extending downwardly into the filler neck and connected to the cover. A valve body having an upper and a lower chamber disposed therein is fitted into the housing and extends downwardly into the filler neck. The upper chamber and lower chamber have vent openings which cooperate with the opening in the cover to provide a vent path to allow the fuel tank to vent fuel vapor to the atmosphere. The lower chamber includes a floatation ball to seal one of the vent openings in the lower chamber to prevent fuel spillage when the vehicle is subjected to a bump, or is operated on a grade. The upper chamber includes a steel ball which seals one of the vent openings in the upper chamber to prevent fuel spillage when the vehicle is overturned to a substantially vertical position. Interposed between the upper and lower chambers is an upwardly biased plunger which, because of cooperation with the steel ball, extends into the lower chamber to prevent the floatation ball from sealing the vent opening in the lower chamber when the vehicle is in an upright position, and is operated normally. When the vehicle is subjected to a bump, or is operated on a grade, the steel ball rolls off of the upwardly biased plunger which allows the floatation ball to seal the vent opening in the lower chamber to prevent fuel spillage.

Harris, U.S. Pat. No. 4,736,863: A cap for closing the filler neck of a vehicle fuel tank is provided. The cap includes a valve body having an upper opening and movable between a normal lower position and an upper position. The valve body includes a ball disposed therein to seal the upper opening when the cap and filler neck are rolled over to a substantially inverted position and vent openings in the side wall that are located somewhat above the level of the ball when the cap and filler neck are substantially upright. When the valve body is in the normal lower position, fuel vapor is allowed to vent to the atmosphere through the vent openings and upper opening in the valve body. If the ball is upwardly and seals the upper opening prematurely, the fuel vapor will form the valve body to the upper position to allow the fuel vapor to continue to vent to the atmosphere around the valve body. In another embodiment of the invention, the cap may include an axially movable plunger to allow the ball to be manually displaced in the event the ball prematurely seals the upper opening.

Harris, U.S. Pat. No. 4,913,303: A fuel cap includes a float valve assembly for minimizing discharge of liquid fuel splash from the filler neck through the pressure-relief vent passage during normal vehicle operation. The float valve assembly is compatible with a controllable pressure-relief valve in the cap that permits venting of the tank under normal conditions and controls fuel leakage from the cap during a roll-over condition.

Szlaga, U.S. Pat. No. 4,953,583: An apparatus is provided for controlling discharge of fuel vapors from a fuel tank during refueling. The apparatus includes a conduit for conducting fuel vapor between the fuel tank and a first destination such as a vapor treatment canister situated outside of the fuel tank, a valve operable between a flow-blocking position and a flow-delivery position for selectively blocking flow of fuel vapor through the conduit, and a spring for yieldably biasing the valve toward its flow-blocking position. A venting control chamber is situated in communication with the valve for receiving and using fuel vapor pressure from the fuel tank having a magnitude in excess of a predetermined threshold level to exert an opening force on the valve in opposition to the spring so that the valve is moved to its flow-delivery position. Such movement of the valve permits discharge of pressurized fuel vapor in the tank to said first destination through the conduit In addition to the foregoing primary venting system, the apparatus is made stageable by including an optional auxiliary system for venting the fuel tank to a second destination.

Keller, U.S. Pat. No. 5,031,790: A vented fuel tank cap and valve assembly is described having a cam actuated connector for connecting the cap to the top of the filler neck tube for the tank. Three vent passages are employed in the cap with common outlet openings. One passage is normally open but includes a float valve which can close such passage when the vehicle tips.

A second passage includes a pressure relief valve which opens when the tank pressure exceeds a predetermined pressure. The bias spring for the pressure relief valve also functions as the bias for the cam actuated connector. The third passage includes fusible metal inserts provided in the movable pressure relief valve member to open such passage when the temperature of the tank exceeds the melting point of such inserts. The cam actuated connector includes ramp shaped cam surfaces on the outside of the filler neck tube and cam follower pins on the tank cap which move along the ramps and are urged into locking notches by a coil spring which also operates the pressure relief valve.

Bae, U.S. Pat. No. 5,971,203: A vent apparatus of a fuel tank comprising a housing having a through-hole at the bottom communicating with a fuel tank; a valve body mounted on the housing, having a flange, vent slots and a partition wall; a lower cover mounted under the valve body, having a through-hole communicating with the through-hole of the housing and the lower space of the valve body; a ball for opening and closing the through-hole of the partition wall of the valve body, a pushing weight mounted on the upper compartment of the valve body, having a protrusion formed on its bottom to prevent adhesion of the ball to the partition wall of the valve body; and an upper cover positioned on the top of the housing, having a plurality of outlets around its periphery. The amount of the gas vapor to be discharged per unit time in proportion to the pressure of the gas vapor in the fuel tank is controlled to maintain a stable pressure in the fuel tank, and the prevention of fuel leakage via vent apparatus, in case that the automobile is overturned, is effectively enhanced.

Hotch, U.S. Pat. No. 6,648,160: A flush-fitting fuel tank cap 110 is described herein. A flush-fitting tank cap 110 having features and advantages of the present invention is preferably characterized by a cylinder portion 30 adapted such that it may screw into a correspondingly threaded gasoline tank neck or bung 100. The tank cap 110 also preferably includes a handle portion 20 which is preferably mounted in operative relationship to the cylinder portion 30 such that rotation of the handle 20 causes corresponding rotation of the cylinder portion 30. The handle 20 is preferably movable between an up and a down position. A pin 40 is preferably disposed at or near the distal end 22 of the handle portion 20. The handle portion 20 is preferably disposed such that the pin 40 may fit into a slot 50 and a notch 54 formed in the cylinder portion. The pin 40 is preferably free to slide linearly within the slot 50, but the pin 40 preferably rotationally engages within the slot such that the handle portion 20 is restrained from rotational motion relative to the cylinder portion 30 while the handle is in the “up” position as described herein.

Hagano, EP 1 162 099: A fuel cap closes the fuel supply inlet of a filler neck at a narrow operating angle, improving the sealing properties of a gasket. The fuel cap has a cap engagement element which is brought into engagement with the opening engagement element of the filler neck, and seals the gap around the filler neck by means of the gasket. The opening engagement element is formed in an inclined state at a predetermined angle relative to the direction orthogonal to the axial direction for closing the cap. The cap engagement element has a guide surface. This surface is aligned and brought into engagement with the opening engagement element by the rotation of the fuel cap in the closing direction when this element is inserted into the filler neck. The guide surface has a first inclined portion with a considerable inclination angle and a second inclined portion whose inclination angle is smaller.

Our prior art search with abstracts described above teaches: a gas cap with automatic pressure compensation, a pressure vacuum relief fuel tank cap with roll-over safety valve feature, a vented fuel cap with bump and grade seal, a ball-valve fuel cap, a liquid splash control fuel cap, a tank pressure control valve, a quick release vent apparatus for a fuel tank, a vented fuel cap with cam actuated connector, a flush fuel cap, and a tank cap with tank cap apparatus.

However, the prior art does not teach a gas cap valve capable of being retrofitted to most common gas caps and which provides for fuel vapor venting, splash suppression and rollover sealing. The present invention fulfills these needs and provides further related advantages as described in the following summary. SUMMARY OF THE INVENTION

A fuel tank cap provides a separable safety valve mounted on the cap"s tubular vent stem for venting fluids from a fuel tank, preventing splashes from passing through the valve and for sealing the cap when the tank moves significantly away from its normal vertical orientation. The safety valve has a lower cavity adapted for retrofit engagement with the tubular vent stem of the cap so that fluids may enter the safety valve from the stem. Two upper cavities communicate with the stem through small flow channels which are not in line with a channel in the stem so that splashes are prevented from moving directly into the two upper cavities. The upper cavities contain valve balls; one free ball seated by gravity, the other by a spring, against valve seats for restricting fluid flow through the upper cavities. Restrictors are positioned for limiting movement of the valve balls away from their valve seats. A safety valve cover is sealingly engaged with the safety valve to form a small chamber above the safety valve. Once fuel vapor reaches the chamber it is able to move through exit channels extending through the safety valve to exit the tank cap. Vapor is able to move around the free valve ball to reach the chamber and from their to exit the cap. A sudden inrush of liquid fuel drives the free valve ball against a sealing seat in its restrictor so that the liquid cannot flow into the chamber or exit. Should the safety valve experience an extreme off-angle position so that liquid fuel fills the tubular vent of the cap, the spring will maintain a seal between the spring loaded ball and its seat, while the free valve ball will, again, be forced against its restrictor and seal against liquid flow.

Another objective is to provide such an invention capable of conducting fluids, primarily fuel vapor, out of a fuel tank and of allowing air to enter the fuel tank depending upon temperature and atmospheric conditions.

A further objective is to provide such an invention capable of preventing liquid fuel from splashing out of the fuel tank when a vehicle experiences rough terrain or when the vehicle is set at an angle to the terrain surface.

A final objective is to provide such an invention capable of emergency venting of fluids when a selected burst pressure is reached within the fuel tank.

FIGS. 4, 5 and 6 are sectional views taken along cutting line 3-3 in FIG. 2 showing the several operational states of parallel valve balls of the invention. DETAILED DESCRIPTION OF THE INVENTION

The present invention, in one embodiment, comprises a fuel tank cap 5 including a tubular vent stem 7 for venting fluids from a fuel tank (not shown). A safety valve 8 has a lower cavity 12 adapted, preferably by threads 14 for engagement with the tubular vent stem 7 so that the fluids may enter the safety valve 8. Preferably, a sealing ring 2 is used to seal safety valve 8 on vent stem 7. See FIG. 3. A first upper cavity 21 and a second upper cavity 31 communicate with the lower cavity 12 through first 22 and second 32 small channels respectively and these channels are set orthogonal to the vent stem 7 so that liquid fuel moving through the vent stem 7 must change direction in reaching the upper cavities 21, 31. This change of direction reduces the amount of momentum force that may be exerted on and carried into the upper cavities 21, 31. The upper cavities 21 and 31 contain a first 23 and second 33 valve balls respectively, where the first valve ball 23 is seated by gravity against a first valve seat 24 in the first upper cavity 21, and the second valve ball 33 is seated by a spring 40, against second valve seat 34 in the second upper cavity 31. The balls 23, 33 restrict fluid flow from the vent stem 7 through the upper cavities 21 and 31. The upper cavities 21 and 31 engage first 25 and second 35 restrictors, respectively, the restrictors 25, 35 positioned within cavities 21, 31 for limiting the magnitude of linear movement of the valve balls 23, 33 away from the valve seats 24, 34. This relationship is best shown in FIGS. 4-6.

Preferably, a cover 50 engages the safety valve 8, preferably by threaded engagement with safety valve external threads 70 and forms a chamber 9 above the safety valve 8 (FIG. 4). At least one, and preferably plural exit channels 15 extend through the safety valve 8 as best shown in FIGS. 1B and 1C. It can be seen by this, that even when a small amount of liquid fuel is able to pass through one or both of the upper cavities 21 or 31 to reach the chamber 9, it is directed downwardly from the chamber 9 through the exit channels 15 to drip into a cap well 6 where it will normally tend to evaporate and escape as vapor as long as the cap 5 is in the upright attitude.

Preferably, the first valve seat 24 provides a groove set 24′ enabling fluids to flow past the first valve ball 23 at a low rate without unseating the first valve ball 23.

Preferably, the first restrictor 25 provides a restrictor valve seat 25′ (FIG. 3) which is configured such that engagement with the first valve ball 23 seals the first upper cavity 21 thereby blocking fluid flow through it.

Under normal conditions, the present invention is mounted on top of a fuel tank and oriented upright relative to the gravity vector as shown in the figures. When ambient temperature changes from warm to cold, as would occur when a motorcycle is taken from a warm garage into a colder outdoor temperature, some fuel vapor within the fuel tank will tend to condense causing the tank vapor pressure to drop below atmospheric and this will cause air to move into the tank through the safety valve 8. In this case, the air cannot move through upper cavity 31 because the second valve ball 33 is sealingly seated against valve seat 34. However, air can move into the fuel tank through the first upper cavity 21 because although the first valve ball 23 is seated against first valve seat 24, seat 24 is constructed, as shown in FIG. 1B with cross-channels 24′ that allow fluids to bypass first valve ball 23.

When the fuel tank is heated, as by incident sunlight, the vapor pressure in the tank will rise and the fuel vapor will tend to move out of the fuel tank through safety valve 8. Again, the fuel vapor is able to bypass fist valve ball 23 and move through the first upper cavity 21 because of the cross-channels 24′ in the first valve seat 24. Gentle movement of air into the fuel tank and vapor out of the fuel tank due to pressure changes occurs with both valve balls 23 and 33 seated as shown in FIG. 4, and air and vapor flows bypassing valve ball 23.

When the fuel tank is jostled due to rough handling or rough terrain, or when the motorcycle leans into a turn or is upended, liquid fuel may be able to move through vent stem 7 and will impinge on the valve balls 23 and 33. Fuel, having greater mass then vapor, will move valve ball 23 away from its valve seat 24 and into contact with restrictor seat 25′ thereby sealing first upper cavity 21 so that liquid fuel is prevented from moving through first upper cavity 21. Liquid fuel is unable to move through the second upper cavity 31 because spring 40 forces the second valve ball 33 against the second valve seat 34 sealing the cavity 31. Such movement of ball 23 against seat 25′, as shown in FIG. 5 is normally momentary and the ball 23 moves back to it nominal position as shown in FIG. 4.

In extraordinary circumstances, such as when a motorcycle might be placed into an inverted attitude during a crash, and if a fire should start causing the fuel tank to heat-up rapidly, the first valve ball 23 is forced into the position shown in FIG. 6 by fuel entering the first upper cavity 21, and the second valve ball 33 will be forced against spring 40 by high vapor pressure in the fuel tank thereby relieving the pressure to forestall an explosion of high pressure gasoline vapor.

To assure that vapor (or liquid) fuel is able to exit well 6 in the fuel tank cap 5, the cover 50 provides plural bumps 52 so that should safety valve 8 and cover 50 tend to be pressed or screwed onto vent stem 7 too forcefully, a space 80 will remain for vapor to exit. Alternatively, a spacer washer 85 may be placed into well 6 so as to prevent space 80 from disappearing.

Motherwell Tank Protection (MTP) manufacture breather valves, pressure vacuum relief valves, emergency relief vents, free vents, Gauge hatchesand level gauges. Supplying industries which include Oil & Gas, Petrochemical, food, water and Biogas

Motherwell Tank Protection, MTP, design and manufacture pressure vacuum relief valves, free vents,gauge hatchand level gauges. All products are designed and manufactured out of our custom built factory based in St Helen’s, UK. We are accredited by the (BSI) British Standards Institute the UK’s national standards organization that produces standards and information on products that promote and share best practice, and also numerous other accreditation’s. We have provided and supplied products to the oil and gas industry worldwide.

Our industry experience and expertise has allowed Motherwell Tank Protection to produce a range of high quality products such as pressure vacuum relief valves, Emergency Relief Vents, Liquid Level Gauges, Gauge hatches and many more. The whole manufacturing procedure is completed by the onsite Tank Fittings Department, resulting in innovative, safe yet cost effective products.

We can trace our manufacturing back to the year 1859 when the Bold Iron Works was established by William Neill & Son Ltd in St Helen’s, England. The company specialise in equipment for Chemical Factories and later for Oil Storage Installations and Oil Refineries. Under the name of Neill-Varec, the company manufactured tank level measuring devices, pressure relief valves and other tank instruments and fittings. The Company later joined the Capper-Neill Group before becoming a member of the Motherwell Bridge Group of Companies in 1984 it was subsequently the subject of a management buyout in 2003. Today, the company is today a wholly owned subsidiary of Motherwell Tank Holdings and specialists in storage tank fittings for the Bulk liquid storage tanks

As well as this, due to aircraft flying where the outside air temperature is extremely cold, this temperature variation affects the pressure the fuel tank is put under, making a pressure relief valve an essential part of any aircraft....

The primary purpose of a safety valve is to protect life, property and the environment. Safety valves are designed to open and release excess pressure from vessels or equipment and then close again.

The function of safety valves differs depending on the load or main type of the valve. The main types of safety valves are spring-loaded, weight-loaded and controlled safety valves.

Regardless of the type or load, safety valves are set to a specific set pressure at which the medium is discharged in a controlled manner, thus preventing overpressure of the equipment. In dependence of several parameters such as the contained medium, the set pressure is individual for each safety application.

As one of the leading manufacturers of cavity free plug valves and special valves, AZ supplies to production plants in the chemical, petrochemical, pharmaceutical, paper, food industries as well as for nuclear power plants and many other areas. Special valves for highest demands in areas with high operating pressures and aggressive, toxic or abrasive media are designed and developed together with our customers. In the 50 years of the company’s existence, AZ has continuously developed to meet the increasing requirements of customers active around the world and today AZ manufactures internationally on four continents.

A safety valve must always be sized and able to vent any source of steam so that the pressure within the protected apparatus cannot exceed the maximum allowable accumulated pressure (MAAP). This not only means that the valve has to be positioned correctly, but that it is also correctly set. The safety valve must then also be sized correctly, enabling it to pass the required amount of steam at the required pressure under all possible fault conditions.

Once the type of safety valve has been established, along with its set pressure and its position in the system, it is necessary to calculate the required discharge capacity of the valve. Once this is known, the required orifice area and nominal size can be determined using the manufacturer’s specifications.

In order to establish the maximum capacity required, the potential flow through all the relevant branches, upstream of the valve, need to be considered.

In applications where there is more than one possible flow path, the sizing of the safety valve becomes more complicated, as there may be a number of alternative methods of determining its size. Where more than one potential flow path exists, the following alternatives should be considered:

This choice is determined by the risk of two or more devices failing simultaneously. If there is the slightest chance that this may occur, the valve must be sized to allow the combined flows of the failed devices to be discharged. However, where the risk is negligible, cost advantages may dictate that the valve should only be sized on the highest fault flow. The choice of method ultimately lies with the company responsible for insuring the plant.

For example, consider the pressure vessel and automatic pump-trap (APT) system as shown in Figure 9.4.1. The unlikely situation is that both the APT and pressure reducing valve (PRV ‘A’) could fail simultaneously. The discharge capacity of safety valve ‘A’ would either be the fault load of the largest PRV, or alternatively, the combined fault load of both the APT and PRV ‘A’.

This document recommends that where multiple flow paths exist, any relevant safety valve should, at all times, be sized on the possibility that relevant upstream pressure control valves may fail simultaneously.

The supply pressure of this system (Figure 9.4.2) is limited by an upstream safety valve with a set pressure of 11.6 bar g. The fault flow through the PRV can be determined using the steam mass flow equation (Equation 3.21.2):

Once the fault load has been determined, it is usually sufficient to size the safety valve using the manufacturer’s capacity charts. A typical example of a capacity chart is shown in Figure 9.4.3. By knowing the required set pressure and discharge capacity, it is possible to select a suitable nominal size. In this example, the set pressure is 4 bar g and the fault flow is 953 kg/h. A DN32/50 safety valve is required with a capacity of 1 284 kg/h.

Coefficients of discharge are specific to any particular safety valve range and will be approved by the manufacturer. If the valve is independently approved, it is given a ‘certified coefficient of discharge’.

This figure is often derated by further multiplying it by a safety factor 0.9, to give a derated coefficient of discharge. Derated coefficient of discharge is termed Kdr= Kd x 0.9

Critical and sub-critical flow - the flow of gas or vapour through an orifice, such as the flow area of a safety valve, increases as the downstream pressure is decreased. This holds true until the critical pressure is reached, and critical flow is achieved. At this point, any further decrease in the downstream pressure will not result in any further increase in flow.

A relationship (called the critical pressure ratio) exists between the critical pressure and the actual relieving pressure, and, for gases flowing through safety valves, is shown by Equation 9.4.2.

Overpressure - Before sizing, the design overpressure of the valve must be established. It is not permitted to calculate the capacity of the valve at a lower overpressure than that at which the coefficient of discharge was established. It is however, permitted to use a higher overpressure (see Table 9.2.1, Module 9.2, for typical overpressure values). For DIN type full lift (Vollhub) valves, the design lift must be achieved at 5% overpressure, but for sizing purposes, an overpressure value of 10% may be used.

For liquid applications, the overpressure is 10% according to AD-Merkblatt A2, DIN 3320, TRD 421 and ASME, but for non-certified ASME valves, it is quite common for a figure of 25% to be used.

Two-phase flow - When sizing safety valves for boiling liquids (e.g. hot water) consideration must be given to vaporisation (flashing) during discharge. It is assumed that the medium is in liquid state when the safety valve is closed and that, when the safety valve opens, part of the liquid vaporises due to the drop in pressure through the safety valve. The resulting flow is referred to as two-phase flow.

The required flow area has to be calculated for the liquid and vapour components of the discharged fluid. The sum of these two areas is then used to select the appropriate orifice size from the chosen valve range. (see Example 9.4.3)

Valves for industrial applicationsIn order to prevent the uncontrolled rise in pressure in pressure vessels or pressurized pipelines, a safety valve is inserted. The safety valve is designed so that it opens at a given maximum pressure, thereby relieving the line or the container. Safety valves find their use in almost all areas of the pressure vessel and pipeline construction. In cryogenics as a spring-loaded safety valve for example.

WITT is a manufacturer of Pressure relief valvesor Safety relief valves for technical gases. They are designed to protect against overpressure by discharging pressurized gases and vapors from pipelines, pressure vessels and plant components. Safety relief valves (SRV) are often the last line of defense against explosion – and such an explosion could be fatal. Other common names for safety relief valves are pressure relief valve (PRV), safety valve, pressure safety valve, overpressure valve, relief valve or blow-off valve.

WITT safety valves are very precise. They are individually preset to open at a predetermined pressure within the range 0.07 to 652 Psi. Their small size and orientation-independent installation allow a wide range of connection options. WITT relief valves also stand out due to their high blow-off flow rates of up to 970m³/h. They can be used within a temperature range of -76° F to +518°F and even with very low pressures.

For maximum safety, WITT undertakes 100 % testing of each safety relief valve before it is delivered. In addition, WITT offers individual testing of eachsafety valveby the TÜV, with their certificate as proof of the correct set pressure.

WITTsafety relief valvesare direct-acting, spring-loaded valves. When the preset opening pressure is reached, a spring-loaded element in the valve gives way and opens, and the pressure is relieved. Once the pressures are equalized, the valve closes automatically and can be reactivated any time the pressure rises again. Depending on the application and the nature of the gas, the safety relief valvescan either discharge to atmosphere, or via a connected blow-off line. The opening pressure of the safety valves is preset by WITT at the factory according to the customer’s requirements.

Safety relief valvesare used in numerous industries and industrial applications where, for example, gases pass through pipelines or where special process vessels have to be filled with gas at a certain pressure.

For most industrial applications using technical gases, brass is usually the standard material of construction of thesafety relief valvebody/housing. For the use of pressure relief valves with aggressive and corrosive gases, the housings are made of high-quality stainless steel (1.4541/AISI 321, 1.4404/AISI 316L, 1.4305/AISI 303 or 1.4571/AISI 316Ti). The use of aluminium as a housing material is also possible.

Depending on the type of gas used and individual customer requirements, various sealing materials and elastomers are available to ensure the safety of your systems under even the most difficult conditions.

WITT pressure relief valves are available with different connections. In addition to the standard versions with the usual internal or external threads, special versions with KF or CF flanges, VCR or UNF threads can also be ordered. Special adapters for connecting the safety relief valve to a blow-off line are also available.

LPG bulk storage products need to be built right using quality materials, to provide years of reliable, safe service. That’s why you need to ask for RegO. We design, built and test 100% of our products in America to ensure you get years of service from all the valves, safety systems and accessories your system requires. When you buy RegO quality, you reduce service time and routine maintenance is easier, that saves you time and money.

RegO internal valves are easily installed and designed to enable smooth operation and higher pumping rates without cavitation or loss of efficiency to save you time and money. They require maintenance less often than other internal valves, and the maintenance is fast and easy. We pay attention to the details, such as superior corrosion prevention and securing fasteners so they don’t come loose and cause damage.

RegO relief valves provide superior protection matched with a long service life. Specifically designed for large stationary pressurized containers our manifold designs provide for an extra relief valve, not included in the flow rating, to enable service or replacement without evacuating the container.

RegO MultiPort relief valve manifolds are used as the primary relief device on LPG bulk storage tanks with flanged openings. The handwheel selectively closes the entrance port to enable service or repair without tank evacuation. RegO “pop-action” design ensures maximum protection, with minimum product loss when replacing a relief valve.

RegO DeltaPort relief valve manifolds are designed to be the primary relief device on LPG bulk storage tanks. The handwheel selectively closes the entrance port to enable service or repair without tank evacuation.

These low profile, internal relief valves are constructed of non-corrosive materials and the RegO “pop-action” design ensures maximum protection, with minimum product loss on relief.

RegO A7500 Series globe valves are constructed with high-quality materials and come in a range of sizes for use in LPG bulk storage applications. Purposefully designed to ensure greater flow with less pressure drop, positive shut-off, and long maintenance-free service; our globe valves provide safety and peace of mind for years. RegO globe valves include these standard features:

At RegO, system and operational safety are paramount. We provide a complete line of products built with RegO ingenuity and quality to deliver years of safe operation.

RegO Back Pressure Check Valves are designed to allow flow in one direction only. When the flow stops or reverses, the check closes. Built to provide generous flow channels for low pressure drop, the heavy-duty construction and synthetic rubber seat discs deliver positive seals for years.

Available in 2” and 3” connections, this back check valve provides back flow protection for the unloading riser. Easy-to-read indicator, heavy-duty spring-loaded swing check design, delivers high flow rates with low pressure drop.

Designed for LPG transfer lines to provide quick shut off of liquid or vapor in the event of an accidental pull-away, line break, or hose rupture. Fusible thermal element auto-shuts valve when exposed to fire. Available with flanged or threaded connections, Viton and Buna-N seat seal options, and a choice of manual, pneumatic, rotary, or electric activation.

Vents less than 2 cc of liquid when disconnected (when connected to RegO low emission ACME filler valves 6588LE, 6589LE.). This valve provides a full-on flow when pressing the release trigger. Compatible with any standard 31⁄4” male ACME connector. California CARB Compliant.

Designed to promote maximum pump and compressor efficiency, these indicators enable visual inspection of liquid flow. The integral swing check also serves as a back-check valve to prevent reverse flow and product loss if the hose fails in a loading operation. Durable ductile iron body ensures long, trouble-free operation with design working pressure of 400 PSIG.

Designed especially for the protection of piping and shut-off valves where there is a possibility of trapping liquid LP-Gas or anhydrous ammonia. Available in both brass and stainless steel.