1. PRESSURE SEAL VALVES

Production Materials
? Carbon Steel : ASTM A216-WCB or Equivalent
? Alloy Steel : ASTM A217-WC6, WC9, C5, C12, C12A, ASTM A182-F91 or Equivalent
? Stainless Steel : ASTM A351-CF8, CF8M, CF3, CF3M, CN7M or Equivalent
? Duplex Stainless Steel : ASTM A995-1A, 2A, 4A, 5A or Equivalent
? Special Alloy Steel : Inconel 625, Incoloy 825, Hastelloy C, Monel ASME SA designation material(e.g ASME SA217-WC6)

Design
Pressure seal valves are intended for high pressure and high temperature appilications in all types of fluid, except where severe coking may occur. A selection of design and material would give an excellent service in nuclear steam generating stations, industrial/chemicaㄴl plants and thermal power plants.
The pressure seal valves provide the most efficient use for folw passage and sealing, and result in significant weight saving and ease and simple installation and maintenance. Manufacturing and quality assurance procedures include extra controls of dimensional and non-destructive examinations and tests on critical areas such as gasket sealing, weld ends, or stellite sealing surfaces.

Construction
? BODY AND BONNET
? BODY : Flow areas are designed for minimum turbulence and pressure drop.
? BONNET : Ample stuffing box and stellite back seat are to guide accurately stem and back seat.
When designing a PK valve, casting of body and bonnet shall be considered thoroughly as a quality requirement.

- BONNET TYPE

2. PARALLEL SLIDE GATE VALVE
Parallel slide gate valves are ideal for high temperature and pressure line to prevent thermal binding.

Features and benefits
Parallel slide construction can be furnished for high differential pressure services or where thermal expansion may cause sticking of a wedge type.

The parallel slide gate assembly consists of two interchangeable spring loaded discs, a fully guided disc
holder, and retaining pins.

Springs are fitted between discs to provide initial sealing force only, and do not maintain the sealing force.

Discs are interchangeable which simplifies in-line maintenance and eliminates the need to custom fit the
seats to the discs.

Position seating eliminates stress and potential binding due to thermal expansion of the stem.

No additional torque required to achieve a positive seal once disc are in position.

Lower seating torque to reduce actuator size and cost.

Hardfaced seating surfaces provide high cycle capability in very high differential pressure services.

By-pass valves are used to reduce the traversing differential pressure across the valve seat.
It reduces the size of the operating gear and also provide a convenient means for the initial warming through of pipe lines.

Equalizing devices are used to relieve the fluid trapped between the seat forces, and to provide an outlet for the fluid displaced by the valve stem traversing to the shut position.