SVP-7200 Pilot Operated Safety Valve

The SVP-7200 pilot operated pressure relief valves are able to operate at considerably higher set pressure than is possible with spring loaded safety relief valves, the valve operation and lift are unaffected by back-pressure.

The AST pilot operated safety relief valves are designed and manufactured according to 97/23/CE P.E.D. and ASME VIII, API527 requirement. They have passed several laboratories tests to obtain the conformance to the Pressure Equipment Directive, PED 97/23CE, accordingly to the product regulation EN ISO 4126-4 for use with gas, vapour and liquid. Many other homologations and approvals are available like ATEX, GOST R for Russia and others.

Different pilots characteristics are available like pop action or modulating, non- flowing or flowing on dependence of customer needs.

AST provide a wide range of materials, flange styles and options to meet the most demanding pressure relief application.

Orifice Sizes: From “D” to “T” according to API 526; full bore orifices available.

Connections: From NPS ½ x 1 to NPS 8 x 10, also available with double outlet flanges

Inlet flanges ratings: Up to Class 2500

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Operating Animation

– Full nozzle design

– Flanged connections can be manufactured according to a wide range of standards

– Bubble-tight seats near set pressure allow high operating pressure and are not as sensitive to vibrational and pulsating service

– Available with metallic or soft seats

– Vertical pilot mounting ensures consistent set pressure and blow-down as contrasted to erratic, horizontally mounted pilots

– All pressurized parts are hydraulically tested

– The high flow coefficients allow the most economical sizing of the valve

– Materials in compliance with NACE standards and wide range of optional exotic materials

– A variety of accessories and options are available like fields test connection, field test indicator, backflow preventer, pilot supply filter, pressure spike snubbers and others

  • For an increased flow capacity full bore pilot operated safety valves are available.
  • Modulating and on-off pilots are available
  1. SVP-7200

    AST SVP 7200 Pilot operated safety valves ares most suitable to handle high back pressure up to 80% of the Set pressure

    Inlet (Inch)        Outlet (Inch)Min. Set Pr. (Bar)Max. Set Pr. (Bar)
    From 1 to 8From 2 to 121425
Safety and Pressure -relief valves should be installed vertically with the drain holes open or piped to a convenient location. All piping must be fully supported.
Maintenance should be performed on a regular basis. An initial inspection interval of no longer than 12 months is recommended. The user must establish an appropriate inspection interval depending on the service conditions, the condition of the valve and the level of performance desired.The ASME Boiler and Pressure Vessel Code does not require nor address testing installed valves. The only thing the code states are design and installation requirements, such as some valves must have a lifting lever. For instance for Section VIII:“Each pressure relief valve on air, water over 140° F, or steam service shall have a substantial lifting device which when activated will release the seating force on the disk when the pressure relief valve is subjected to a pressure of at least 75% of the set pressure of the valve.”
Installing a safety valve in any position other than with the spindle vertical and upright may adversely affect performance and lifetime.
This drain hole is required on some models by the ASME Boiler and Pressure Vessel Code. It is intended to prevent any condensate from accumulating in the body that may freeze or corrode internal valve parts and prevent the valve from opening. The drain hole should be piped away to safely dispose of any discharge or condensate.
Typically, the valve should be nameplate set to open at the MAWP (Maximum Allowable Working Pressure) of the vessel the valve is intended to protect. There is a tolerance to actual set pressure.
Maintain a minimum operating gap of 10% between the system operating pressure and the safety valve’s nameplate set pressure. Since direct spring-operated safety valves may “simmer” or “warn” at 90% of the nameplate set pressure, and since the factory standard leak test is performed at 90% of nameplate set pressure, better seat tightness performance can be expected with an operating gap of 10%.
 It may not be. Warn/simmer or seat leakage is sometimes mistaken for set pressure. Visible or audible leakage or system pressure drop is not set pressure. The correct definition of set pressure is:
·        For steam or most valves in air/gas service, “pop” (an audible loud pop) – SMS 7100
·        For liquid service, first vertical steady stream
·        For some valves in air/gas service (SMU -7000 ), first audible
Rapid increases in system pressure (more than 2 psig/second, water hammer, reciprocating pumps) can make the valve appear to be opening early because the gage cannot accurately report the pressure to which the valve is exposed.
Yes. Section I valves have more stringent setting blowdown requirements and may be used in Section VIII steam applications since they meet all the requirements as specified in Section VIII UG-125(a) “Pressure Relief Devices,” which states pressure relief devices must be “in accordance with the requirements of UG-125 through UG-137.” In addition, UG-125(b) actually specifies that even unfired steam boilers MUST use a Section I pressure relief device.
Section VIII UG-136(a)(3) states, “Each pressure relief valve on air, water over 140° F (60° C), or steam service shall have a substantial lifting device which when activated will release the seating force on the disk when the pressure relief valve is subjected to a pressure of at least 75% of the set pressure of the valve.”
The user has a documented procedure and an associated implementation program for the periodic removal of the pressure relief valves for inspection and testing, and repair as necessary.
The omission is specified by the user.
·        The user shall obtain permission to omit the lifting device from the authority having jurisdiction over the installation of pressure vessels.
Back pressure reduces set pressure on a one-to-one basis, i.e., a valve set at 100 psig subjected to a backpressure at the outlet of 10 psig will not actuate until system pressure reaches 110 psig. Back pressure drastically reduces capacity; typically backpressure of 10% of set pressure will decrease capacity by 50%. Specific capacity reduction should be determined by the user on a case-by-case basis by flow testing. Back pressure in excess of 10% of set pressure is not recommended.