Masoneilan 21000 API 6A High Pressure Cage-Guided Control Valve

Overview

The Masoneilan 21000 API 6A is the high pressure version of the Baker Hughes Masoneilan 21000 Series globe control valve. It is a single-ported, cage-guided control valve designed to meet the API 6A standard for high pressure applications, offered in 3/4 and 1 inch trim sizes with API pressure classes from 10 kPSI (690 bar) to 15 kPSI (1034 bar). Where the standard 21000 body is cast and flanged to ASME Class 150 to 2500, the Masoneilan 21000 API 6A swaps to a forged body and an integral bonnet so that the pressure envelope can climb well beyond the ASME range while the valve stays compact.

As the official trusted supplier of Masoneilan in the Sultanate of Oman, Seven Star LLC supplies the Masoneilan 21000 API 6A together with the standard 21000 range to oil and gas operators, EPC contractors and service companies across the GCC. Our valve team in Muscat can review the fluid, the pressure drop at the valve and the sour or sweet classification of the service, and then confirm the material class and temperature class that apply before a formal RFQ is raised.

What API 6A Means for the Masoneilan 21000 API 6A

API 6A is the specification used for wellhead and tree equipment, and it is written around pressure containing parts that must be traceable, tested and made from controlled materials. In the Baker Hughes technical specification the Masoneilan 21000 API 6A is described as a valve that follows this approach: the forged body is designed to meet 15 kPSI (1034 bar) in operation, the body and the integral plug and stem are marked as pressure containing parts under the API 6A specification, and the serial plate records the working pressure, the material class, the temperature class, the product specification level and the performance requirement used for the pressurized chamber. A buyer who has to document a wellhead package therefore receives a valve whose identification matches the language of the purchase specification.

One limit deserves attention before the Masoneilan 21000 API 6A is selected. For the 15 kPSI valve, Baker Hughes limits the pressure drop to 10 kPSI (690 bar), and the Masoneilan 21000 API 6A is designed as a control valve, not as an isolating valve. The instruction manual repeats the point: the valve should be closed only for a short period, because long periods in the closed position risk damage to the trim parts, and damage caused by using the valve as an isolation valve is not covered by warranty. Isolation should be provided by a separate block valve.

Engineering Design of the Masoneilan 21000 API 6A

The Masoneilan 21000 API 6A is built around an integral seat ring and cage, so the seat and cage are one piece. Baker Hughes states that this arrangement allows ease of installation and maintenance, and it removes a separate seat joint from the high pressure path. The plug and stem of the Masoneilan 21000 API 6A are also a single integral part, which carries the trim in a heavy, simple assembly. A trim retainer, a seat ring gasket and a packing set complete the body sub-assembly, and the integral packing flange and follower together with the integral bonnet give the valve a smaller profile and lower weight than a bolted bonnet of equal rating.

End connections are API type, with a 1 inch 13/16 (1.8125) valve end size and a 6BX flange configuration for both the 10K and 15K ratings. Lifting lugs are provided for handling. The standard dimensions are listed in the specification for the two sizes: the 3/4 inch valve measures 160 mm in dimension A and weighs 61 kg (134 lb), while the 1 inch valve measures 200 mm in dimension A and weighs 88 kg (194 lb). Both Masoneilan 21000 API 6A bodies show a 46.45 mm inlet and outlet diameter.

Trim, Flow Characteristic and Cv of the Masoneilan 21000 API 6A

The Masoneilan 21000 API 6A uses a contoured, linear trim, and Baker Hughes lists both flow-to-open and flow-to-close models under the 21114 designation. Full area and reduced trims are available, with the orifice diameter chosen to fit the required capacity. In the flow-to-open direction the 3/4 inch valve is offered with a 0.25 inch (6.35 mm) orifice and a 0.375 inch (9.53 mm) orifice, with rated Cv up to 3.8 at 100 percent travel, and the 1 inch valve is offered with a 0.50 inch (12.70 mm) and a 0.812 inch (20.64 mm) orifice, with rated Cv up to 12. The critical flow factor FL falls from 0.93 at 10 percent travel to 0.90 at full travel. Travel is 0.8 inch (20.32 mm) in every case.

In the flow-to-close direction the Masoneilan 21000 API 6A bodies deliver slightly higher rated Cv, up to 4.2 for the 3/4 inch valve and up to 13 for the 1 inch valve, but FL is much lower: 0.53 at 10 percent travel rising to 0.86 at 100 percent. The practical consequence is that flow-to-open is the choice where the liquid may approach cavitation, while flow-to-close gives more capacity from the same orifice. On the Masoneilan 21000 API 6A, Class IV and Class V seat leakage to IEC 60534-4 is standard, and hardened trim is provided for a longer service life at high pressure.

Materials and Temperature Classes

The Masoneilan 21000 API 6A is offered in four body and trim material families: martensitic stainless steel ASTM A182 grade F6NM, duplex stainless steel F51, super duplex stainless steel F55 and the nickel alloy Inconel 718 (UNS N07718). The material classes AA, BB and CC are general service. Classes DD, EE, FF and HH are sour service, with F6NM, F51 and F55 available in class FF and Inconel 718 available in all of them. Baker Hughes states that NACE MR0175 and ISO 15156-1 compatible materials are available. The maximum operating pressure is 15 kPSI (1034 bar) for the F6NM, F55 and Inconel 718 constructions and 10 kPSI (690 bar) for the duplex F51 construction.

Temperature classes for the Masoneilan 21000 API 6A run from K to X. Class K covers -60°C to +82°C (-75°F to +180°F) for F6NM and Inconel 718, class L covers -46°C to +82°C, class P covers -29°C to +82°C, and class X reaches 0°C to +180°C (0°F to +350°F). With the standard PTFE packing and a metal seat the overall range is -60°C to +180°C for F6NM and Inconel 718 and -46°C to +180°C for the two duplex steels. Packing rings are Lattyflon 3265 LM with Lattygraf 6995NG anti-extrusion rings, and Baker Hughes offers environmental Low-E packing where fugitive emission limits apply.

Maintenance Notes from the Instruction Manual

The Baker Hughes manual includes an appendix written for the Masoneilan 21000 API 6A alone. It requires the Masoneilan 21000 API 6A to be reassembled with new packing rings and gaskets, specifies four PTFE packing rings and two anti-extrusion rings for the 3/4 and 1 inch stem sizes, and gives trim retainer torque values of 14 daN.m (103.3 ft-lb) for the 3/4 inch valve and 27 daN.m (199.2 ft-lb) for the 1 inch valve. On the Masoneilan 21000 API 6A the cage window must be oriented with the flow direction when the trim is installed. Because sealing surfaces on a high pressure valve depend on surface roughness, the manual asks the technician to inspect the body, cage and plug for nicks, scratches and burrs before every assembly.

Key Features

The following points summarise what distinguishes the Masoneilan 21000 API 6A from the standard 21000 body:

• Designed to meet the API 6A standard, with API classes of 10 kPSI (690 bar) and 15 kPSI (1034 bar) in 3/4 and 1 inch sizes.
• Forged body rated for 15 kPSI (1034 bar) in operation, with pressure containing parts identified under the API 6A specification.
• Integral bonnet gives a smaller profile and reduced weight compared with a bolted bonnet design.
• One-piece integral seat ring and cage for easier installation and maintenance.
• Hardened trim and linear flow characteristic as standard, with full area and reduced orifice options.
• Class IV and Class V seat leakage to IEC 60534-4 as standard.
• Four material families: F6NM, duplex F51, super duplex F55 and Inconel 718, with general and sour service classes.
• Standard packing or environmental Low-E packing, and lifting lugs supplied for handling.

Industrial Applications

The Masoneilan 21000 API 6A suits control duties at wellhead pressure levels, where a conventional ASME flanged body would run out of rating: high pressure gas injection and lift, chemical and methanol injection, pressure letdown on production manifolds and the control of test separators and skid-mounted packages. Sour fluids from the interior of Oman call, for the Masoneilan 21000 API 6A, for the FF or Inconel 718 material classes, while offshore and splash zone installations need the elimination of zinc plating that the specification notes for subsea service. Facilities in the Sohar and Salalah economic zones that handle high pressure gas or process fluids can use the same valve in test loops and pilot plants.

In Oman and the GCC, Seven Star LLC supplies the Masoneilan 21000 API 6A to operators and contractors in Oman and across the GCC. Many projects also need the standard Masoneilan 21000 Series seal kit for lower-pressure valves in the same plant, and large cage-guided bodies are covered by the Masoneilan 41005 Series cage guided control valve. For positioning, a Masoneilan SVI3 digital valve positioner can be added to the actuator package.

Technical Specifications

The table summarises the principal published data of the Masoneilan 21000 API 6A from the Baker Hughes 21000 Series technical specification and the API 6A appendix of the instruction manual. Confirm the complete data against the official documents before final selection.

The complete 21000 family, including Lo-dB and anti-cavitation trims, is described on the Masoneilan 21000 Series top-guided globe control valve page.

Request a Quote for Masoneilan 21000 API 6A

Engineers and procurement teams in Oman and across the GCC can send Seven Star LLC a formal RFQ for the Masoneilan 21000 API 6A with the working pressure, pressure drop, fluid, sour or sweet classification, temperature and required material class stated, so that the correct API class and trim can be confirmed. Regional availability is checked, and the Baker Hughes technical specification and instruction manual can be downloaded from this page. In Oman and the GCC, we back every valve with manufacturer documentation and local support from our Muscat instrumentation division.