12" Class 1500 Pressure Seal Bonnet Gate Valve (Z560Y) — A216 WCB, Butt-Weld Ends, Gear Operated

This 12 inch Class 1500 cast steel gate valve uses the pressure seal bonnet (PSB) design and is designated model Z560Y in the Chinese national model system. The valve is the OS&Y rising stem, flexible wedge, backseat design in ASTM A216 WCB with a Stellite hardfaced seat and wedge (Trim 5 / Trim 8). Butt-weld ends are to ASME B16.25, face-to-face to ASME B16.10, and pressure-temperature ratings to ASME B16.34. At 12 inch and Class 1500, a bevel gear operator is supplied as standard. The valve is API 598 tested, and RT, LP and MT non-destructive testing are available on request for the body casting, weld-end preparation and pressure seal area.

Application

This 12 inch Class 1500 pressure seal gate valve is specified in high-pressure oil and gas production, petrochemical and refinery process lines, power generation and high-energy utility service. The pressure seal bonnet is used because the internal pressure at Class 1500 makes a bolted bonnet design impractical, and the butt-weld ends eliminate the flange gasket as a potential leak path at high pressure. For sour service the valve can be supplied to NACE MR0175 / ISO 15156 on request.

Standards

Design and Manufacture: Cast steel gate valve to API 600 or API 6D.
Inspection and Test: API 598, API 600 or API 6D.
BW end dimension: ASME B16.25.
Face to face and end to end: ASME B16.10.
Pressure-temperature ratings: ASME B16.34.

Quick Details

1. Product: Pressure seal bonnet (PSB) gate valve
2. Model: Z560Y
3. Design: PSB, flexible wedge design
4. Size: 12 inch (DN300)
5. Pressure Rating: ASME Class 1500LB / 1500#
6. Body Material: ASTM A216 WCB cast carbon steel
7. Various trim materials are available to suit different service conditions
8. Actuator: Bevel gear operated as standard
9. Special Requirement: NACE MR0175 on request
10. Special Testing: RT, LP, MT inspection

Selection Notes: PSB, BW Ends and Gear Operation at 12" Class 1500

Why pressure seal at 12" Class 1500: at Class 1500 and 12 inch, the internal pressure acting on the bonnet area is very high. A bolted bonnet design would require extremely large and numerous studs to hold the gasket seal against that pressure, making the valve heavy and difficult to assemble and disassemble. In a pressure seal bonnet, the internal pressure acts on a sealing ring seated between the bonnet and the body — the higher the pressure, the tighter the seal. The bonnet studs only need to hold the assembly together during assembly and low-pressure conditions, not to resist the full pressure load. This is why pressure seal construction is standard practice at Class 1500 and above.

Why butt-weld (BW) ends: BW ends are specified when the line is to be welded rather than bolted at the valve connection. At Class 1500, this eliminates the flange gasket as a potential leak path and reduces the overall envelope in the line. BW is common on high-pressure and sour gas lines, on buried or subsea piping where flanged joints are not accessible, and in pipeline construction where the entire line is welded. The weld-end preparation follows ASME B16.25, and RT / LP / MT can be applied to the weld-end preparation on request.

Why bevel gear at 12" Class 1500: at 12 inch and Class 1500, the torque required to open or close the valve against full differential pressure exceeds what an operator can reasonably apply through a plain handwheel. A bevel gear box multiplies the input torque and reduces the number of handwheel turns, making manual operation practical for one person. The gear box is supplied as standard on this 12 inch valve; electric or pneumatic actuation can be quoted on request.

Model interpretation: Z560Y is a Chinese national standard model designation. Z denotes gate valve, 5 denotes the pressure seal bonnet structure, 6 denotes the welding (butt-weld) end connection, 0 denotes the structural form, and Y denotes the sealing surface material (hard alloy, typically Stellite or 13Cr). In international specification, the valve is referred to as an API 600 pressure seal gate valve with BW ends, and the Z560Y designation is normally quoted alongside the API standard to avoid ambiguity.

Features

1. Bonnet Gasket Style
Pressure seal design is used for Class 1500 gate valve.

2. Packing Seal
As usual, flexible graphite is used for packing material. PTFE or combined packing material can also be used if requested by the customer.

3. Body and Bonnet Connection
Class 1500 gate valves adopt pressure seal bonnet design.

4. Seat
For carbon steel gate valve, the seat is usually forged steel. The seat sealing surface is overlay welded with hard alloy specified by the customer. For stainless steel gate valve, the seat is integral with body, or it can be machined directly after hard alloy welding.

5. Disc Design
NPS ≥ 2 gate valves are flexible wedge gate.

6. Backseat Design
All gate valves have backseat 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 machined after welding.

7. Stem Design
The stem is integral forged design. The minimum diameter of the stem shall be as per the standard requirement.

8. Stem Nut
Usually, the stem nut is made of ASTM A439 D2. It can also be made of copper alloy or other materials if requested by the customer.

9. Operation
Hand wheel or bevel gear box is usually used for gate valve operation. At 12 inch Class 1500, a bevel gear box is supplied as standard.

Pressure Seal Gate Valve Design Drawing (Class 1500–2500)

Pressure Seal Bonnet Cast Steel Gate Valve Parts and Material List (Class 1500LB)

Swipe horizontally to see all materials

Yoke row: original source listed "WCB" without the ASTM prefix — normalised to ASTM A216 WCB to match the other rows. Bonnet Stud / Bonnet Stud Nut: original source used hyphenated designations (A193-B7 / A194-2H) — normalised to ASTM A193 B7 / ASTM A194 2H for consistency with the other product pages. Adapter Ring, Retainer and Yoke Cap are listed as "Carbon steel" in the original; these are general material designations and are confirmed against the material certificate at the time of order.

Main Connection Dimensions — Class 1500LB (mm)

Swipe horizontally to see all dimensions · The highlighted row is the 12" size of this page

Dimensions in mm. L = face-to-face (RF / RTJ) or end-to-end (BW) per ASME B16.10. The highlighted row is the 12" size covered by this product page; the other sizes are listed for reference. This valve is supplied with BW ends as standard, so the L (BW) column is the applicable dimension for this product. RF and RTJ dimensions are listed for reference when the same valve is specified with flanged ends.

Frequently Asked Questions