model steam engine safety valve for sale

These safety valves use a stainless steel ball and spring in a brass body. They are set to blow at approximately 60psi. Threaded 5/16-27 Female (1/16 NPT).

After a boiler has been engineered, built and tested for a given operating pressure there is only one reliable way to prevent operation of the boiler above this design pressure.  This is a safety valve.  The safety valve should be sized so that a single valve can handle the maximum steam production rate of the boiler and once open prevent boiler pressure to continue to rise.  Standard operating procedure for the last century has been to install two safety valves on the boiler, one set 3-5 lbs below the design pressure and one valve set at the design pressure.

The 1st valve listed below is a true adjustable differential pop valve.  The differential is adjured through the differential rings lock screw hole, from 3 PSI to whatever the operator desires.  The pressure of the valve can be adjusted from 40 to 200 PSI.

The other valves listed are adjustable for release pressure and have a "pop" action:  The pressure differential is not adjustable on these valves.  If the valves are operated above their nominal pressure, the set-reset differential increases.  If operated at lower pressure, the differential decreases to the point of disappearing about 10-15% below nominal pressure.

Note: these have simple adjustable spring loaded relief balls/surfaces that progressively release pressure when the setting is passed. They are not "pop"valves that trigger at a set pressure.

Kunkle Relief Valve OverviewWhen it comes to industrial and commercial safety and relief valve products, Kunkle’s valve’s catalog is second to none in steam, air, gas, and liquid applications.

Kunkle relief valves range in size from ¼” NPT to 6” flange and are suitable in cryogenic and high temperatures up to 800°F environments at vacuum to 7,500 psig pressure. Kunkle Valve’s code certifications meet several global and national board standards, including ASME Section I, Section IV, and Section VIII, PED, CRN, TU and Chinese, as well as non-code requirements.

Relief Valves for Steam ServiceSteam supplies heat for industrial and chemical processes and also is used to heat buildings, supply mechanical energy, and drive mechanical equipment. Steam moves from the boiler to the end point, then heats by direct heating or indirect heating through a heat exchanger. Kunkle steam relief valves are critical to protecting equipment such as boilers, steam lines, and pressure valves, from being over-pressurized.

Relief Valves for Air ServiceKunkle designs valves for air service, for example for air compressors in mechanical shops and small factories where either low-pressure or high-pressure air is required. NASVI stocks Kunkle relief valves for air service in iron, steel and bronze for a variety of uses.

Relief Valves for Liquid ServiceKunkle also makes valves for liquid service, which provide bypass relief in a variety of applications and liquid types.

More About KunkleKunkle Valve is a renowned pressure relief valve manufacturer. Erastus B. Kunkle invented the safety valve to prevent overpressure in locomotive engines. Kunkle patented it in 1875. Since that time, Kunkle has earned its reputation for high-quality valves, and other equipment manufacturers ship their products with Kunkle’s valves pre-installed.

NASVI has stocked Kunkle safety relief valves since we opened in 1975, so we are confident when we call ourselves Kunkle safety valve experts. Every day we fulfill orders for our customers looking for Kunkle relief valves for steam, air, gas, and liquid applications.

Wilesco D10 steam engine with mirror polished and nickel plated boiler, diameter 1.75", length 4.5", boiler capacity 9.4", with water gauge glass. Boiler house true to life, col…

A safety valve is a valve mechanism for the automatic release of steam from the boiler of a steam locomotive, which helps prevent from a steam locomotive from exploding.

Safety valves were first used on steam locomotives during the industrial revolution in the late-1800"s. Early boilers without them were prone to accidental explosion.

Vacuum safety valves (or combined pressure/vacuum safety valves) are used to prevent a tank from collapsing while emptying it or when cold rinse water is used after hot water.

The calculation method is not defined in any normal temperature when sizing a vacuum safety valve, particularly in the hot/cold water scenario, but some manufacturers have developed simulations to do so.

Boiler explosions have been responsible for widespread damage to companies throughout the years, and that’s why today’s boilers are equipped with safety valves and/or relief valves. Boiler safety valves are designed to prevent excess pressure, which is usually responsible for those devastating explosions. That said, to ensure that boiler safety valves are working properly and providing adequate protection, they must meet regulatory specifications and require ongoing maintenance and periodic testing. Without these precautions, malfunctioning safety valves may fail, resulting in potentially disastrous consequences.

Boiler safety valves are activated by upstream pressure. If the pressure exceeds a defined threshold, the valve activates and automatically releases pressure. Typically used for gas or vapor service, boiler safety valves pop fully open once a pressure threshold is reached and remain open until the boiler pressure reaches a pre-defined, safe lower pressure.

Boiler relief valves serve the same purpose – automatically lowering boiler pressure – but they function a bit differently than safety valves. A relief valve doesn’t open fully when pressure exceeds a defined threshold; instead, it opens gradually when the pressure threshold is exceeded and closes gradually until the lower, safe threshold is reached. Boiler relief valves are typically used for liquid service.

There are also devices known as “safety relief valves” which have the characteristics of both types discussed above. Safety relief valves can be used for either liquid or gas or vapor service.

Nameplates must be fastened securely and permanently to the safety valve and remain readable throughout the lifespan of the valve, so durability is key.

The National Board of Boiler and Pressure Vessel Inspectors offers guidance and recommendations on boiler and pressure vessel safety rules and regulations. However, most individual states set forth their own rules and regulations, and while they may be similar across states, it’s important to ensure that your boiler safety valves meet all state and local regulatory requirements.

The National Board published NB-131, Recommended Boiler and Pressure Vessel Safety Legislation, and NB-132, Recommended Administrative Boiler and Pressure Vessel Safety Rules and Regulationsin order to provide guidance and encourage the development of crucial safety laws in jurisdictions that currently have no laws in place for the “proper construction, installation, inspection, operation, maintenance, alterations, and repairs” necessary to protect workers and the public from dangerous boiler and pressure vessel explosions that may occur without these safeguards in place.

The American Society of Mechanical Engineers (ASME) governs the code that establishes guidelines and requirements for safety valves. Note that it’s up to plant personnel to familiarize themselves with the requirements and understand which parts of the code apply to specific parts of the plant’s steam systems.

High steam capacity requirements, physical or economic constraints may make the use of a single safety valve impossible. In these cases, using multiple safety valves on the same system is considered an acceptable practice, provided that proper sizing and installation requirements are met – including an appropriately sized vent pipe that accounts for the total steam venting capacity of all valves when open at the same time.

The lowest rating (MAWP or maximum allowable working pressure) should always be used among all safety devices within a system, including boilers, pressure vessels, and equipment piping systems, to determine the safety valve set pressure.

Avoid isolating safety valves from the system, such as by installing intervening shut-off valves located between the steam component or system and the inlet.

Contact the valve supplier immediately for any safety valve with a broken wire seal, as this indicates that the valve is unsafe for use. Safety valves are sealed and certified in order to prevent tampering that can prevent proper function.

Avoid attaching vent discharge piping directly to a safety valve, which may place unnecessary weight and additional stress on the valve, altering the set pressure.