Description

Full port design, OS&Y, BB, Flexible/solid wedge, renewable seat rings, forged T-head stem, Rising stem and non-rising handwheel, flanged or butt welding ends, available with BG operator.

Standards

• Design and Manufacture: Cast steel gate valve to API 600(ISO 10434) or API 6D; Cast stainless steel gate valve to API 603 or API 600; Forged steel gate valve to API 602. Inspection and Test: API 598, API 600 or API 6D

• End flange dimension: ASME B16.5(for PS <24): ASME B16.47 series B. API 605 or ASME B16.47 series A.

MSS SP -44(for NPS > 24).

• BW end dimension: ASME B16.25.

• Face to face and end to end: ASME B16.10.

• Socket-weld dimension: ASME B16.11

• Pressure-temperature rating: ASME B16.34

Design of disc

• Gate Valves with NPS≥2 are of wedge flexible gate; Gate valves with NPS < 2 are of wedge solid gate

Body and bonnet connection

• The body and bonnet of Class 150 ~ Class900 gate valves are usually connected with studs and nuts. And the body and bonnet of Class 1500 ~ Class2500 gate valves are usually of pressure seal design

Gasket of cover flange

• Carbon steel or stainless steel + flexible graphite combined gasket is used for Class 150 gate valve; Stainless steel+ flexible graphite wounded gasket is used for Class300 gate valve; Stainless steel + flexible graphite wounded gasket is used for Class600 gate valve, and ring joint gasket is also optional for Class600 gate valve;Ring Joint gasket is used for Class 900 gate valve; Pressurized seal design is used forClass1500 ~ Class500 gate valve

Actuation

• Hand wheel or gear box is usually used for gate valve actuation. Chain wheel and electric actuator can be also used for gate valve actuation if being requested by the customers.

Belleville spring loaded packing ; Impacting system

• If being requested by the customer, the Belleville spring loaded packing impacting system can be adopted for enhancing the durability and reliability of the packing seal.

Packing seal

• Molded flexible graphite is used for packing material. PTFE or combined packing material can be also used if being requested by the customer. The internal surface of the stuffing box, of which area is contacted with the packing, is of excellent finish (Ra3.2 u m). The stem surface, contacting with the packing, should be rolled and pressed after being precisely machined, so as to reach the high finish and compactness (Ra0.8 m m) and ensure the reliable tightness of the stem area.

Back seating design

• All our gate valves have the back seating design. In most cases, the carbon steel gate valve is fitted with a renewable back seat. For stainless steel gate valve, the back seat is machined directly in the bonnet or is machined after welding. When the gate valve is at fully open position, the sealing of the back seat can be very reliable. However, as per the requirement of API 600, it is not advisable to add or change packing by the mean of back seating when the valve is Pressure containing

seat

• For carbon steel gate valve, the seat is usually forged steel. The sealing surface of the seat is spray welded with hard alloy specified by the customer. Renewable threaded seat is used for NPS < 10*gate valves, and welded on seat can be also optional if being requested by the customer. Welded on seat is used for NPS > 10* carbon steel gate valves. For Stainless steel gate valve, integral seat is usually adopted, or to weld hard alloy directly integrally. Threaded or welded on seat is also optional for stainless steel gate valve if being requested by the customer.

Stem design

The stem is of integral forged design. The minimum diameter of the stem shall per the standard requirement.The connection of the stem and disc is T type. The strength of the connecting area is bigger than that of the T type threaded part of the stem. The strength test of that area conforms to AP1591.

Stem nut

• Usually, the stem nut is made of copper alloy. It also can be made of AST A439 D2 if requested by the customer. For large-sized gate valves (NPS10 for Class 150, NPS8 for Class 300, NPS6 for Class 600, NPS 5 for Class 900), a rolling bearing is fitted at the two sides of the stem nut in order to minimize the open and close torque of the gate valve.

Special gate valve

• Besides the common gate valves, PANS also makes stainless steel 304 gate valves, cryogenic gate valves, Jacketed Gate Valve, Bellow Sealed Gate Valve, Extension Stem Gate Valve for underground applications, Slat Gate Valve, etc.