Masoneilan 536H Single-Seat Back Pressure Regulator
Overview
The Masoneilan 536H is the back pressure regulator of the 535H/536H range from Baker Hughes. The digits of its model code read 5 for regulator type, 3 for a single-seat body and 6 for back pressure action, with the letter H marking the 21000 body, and the instruction manual lists this service as upstream pressure controlled in its Figure 1b. The Masoneilan 536H therefore holds the pressure on its inlet side steady and lets the excess flow pass through, which makes it a neat solution for small sustaining and pressure-holding duties on steam, gas and liquid lines where flows are small to moderate, with nominal Cv from 1.4 to 27.
Across Oman and the GCC, Seven Star LLC is a trusted supplier of Masoneilan products supplying the Masoneilan 536H to process engineers, skid builders and maintenance planners. Our Muscat instrumentation team selects orifice, actuator and spring range from your upstream pressure and flow figures and attaches the Baker Hughes technical specification and instruction manual to each quotation. The 536H-50 differential back pressure variant and the EB extended bonnet for hot service are covered by the same documents.
Back Pressure Service of the Masoneilan 536H
A back pressure regulator opens as the pressure on its inlet rises above the set point and closes as it falls back, so the Masoneilan 536H holds the upstream system at a constant level. The commissioning sequence in the manual starts with the outlet stop valve opened and the inlet stop valve opened partly, so that system pressure builds slowly, followed by opening of the control line valve and a check of the setting on a gauge; clockwise rotation of the adjusting screw compresses the spring and raises the setting. If no pressure is specified the regulator leaves the factory set at the minimum of the range printed on the serial plate.
The sensing line is run to the 1/2 inch NPT connection in the diaphragm case from a convenient point 6 to 10 feet from the regulator, with a gauge and a needle valve that also acts as a choke against pump pulsation. The manual has a figure of a typical back pressure application with a 536H regulator. The unit is installed in a horizontal run following the flow arrow, on steam service with the diaphragm actuator down, and with a three-valve bypass that lets the regulator come out of the line without a shutdown.
Engineering Design of the Masoneilan 536H
The Masoneilan 536H shares the high-capacity globe body, heavy top-guided disc plug, quick-opening characteristic and flow-to-open direction of the 535H, but its trim is limited to the quick-change design. A 304 stainless steel cage and a spiral-wound seat ring gasket sit between the seat ring and the bonnet, and the manual explains that the bonnet holds them in position, so lifting the bonnet with the stem and plug exposes the cage, the seat ring and the gasket for inspection and lapping. This is the maintenance route documented in section 7.2 of the manual for quick-change trim, and a new gasket is required whenever the valve is opened.
The orifice table shows a feature that is specific to the 536H. For the four smallest trims of nominal Cv 1.4, 2.4, 4.4 and 6.5 the 536H orifice diameter is 0.900 inch (23 mm), where the 535H orifices step from 0.250 to 0.810 inch, and the Cv is set by the reduced-area trim. For the Cv 19.5 and 27 trims the orifice is 1.250 and 1.625 inch like the 535H. Seat leakage is Class IV with the hard seat; the soft seat of Class VI is offered only on the 535H. Packing is carbon core PTFE jacketed or braided PTFE, and the skive-cut rings can be replaced without disconnecting the stem.
Key Features
The Masoneilan 536H is specified for upstream pressure control for these reasons:
- Self-operated back pressure control with a 10900 spring-diaphragm actuator and no external power supply.
- Quick-change trim only, with the cage and seat ring withdrawn together with the bonnet.
- Nominal Cv steps of 1.4, 2.4, 4.4, 6.5, 19.5 and 27 are offered, in 3/4 to 2 inch bodies.
- Class IV shut-off with standard or hardfaced 316 stainless steel trim.
- 536H-50 differential back pressure option and EB extended bonnet above 450°F (232°C).
- Carbon steel, stainless or chrome-moly metal can be chosen for the body and bonnet.
- Flanged, threaded and socket weld ends follow the ASME Class 150-600 and ISO/DIN PN options.
- Useful life is estimated at over 25 years with yearly inspection, according to the manual.
Industrial Applications
Typical uses of the Masoneilan 536H include holding the pressure on a steam condensate or heating return, keeping a constant pressure at a small pump discharge, sustaining pressure in a gas header or on a separator and protecting upstream equipment from dropping below a minimum pressure. In Oman the compact body suits laboratory and pilot plants, packaged units for oil and gas sites, utility rooms in Muscat and Salalah, and OEM skids built for industrial customers in Sohar and Duqm.
In Oman and the GCC, Seven Star LLC supplies the Masoneilan 536H with the instrumented alternative of the Masoneilan 10000 Series double port valve when a loop with positioner is needed. The reducing model on the same body is the 535H, and both use the same 10900 actuators.
Technical Specifications
These tables list data for the Masoneilan 536H from the 535H/536H/535V technical specification, which also holds the full steam, gas and water capacity tables.
| Parameter | Specification |
|---|---|
| Model | Masoneilan 536H back pressure (536H-50 differential back pressure; EB extended bonnet option) |
| Controlled pressure | Upstream (manual Figure 1b) |
| Service | Steam, gas, liquids |
| Body | 21000 body, single seat, flow to open, high capacity globe pattern |
| Trim | Disc plug, heavy top guided, quick-change seat ring only |
| Characteristic | Quick opening |
| Seat leakage | Class IV hard seat (soft seat is 535H only) |
| Flanges | ISO or DIN PN 10 to 100, or ASME Class 150, 300 and 600 |
| Actuator | 10900 Series spring-diaphragm |
536H orifice diameter and nominal Cv
| Nominal Cv | 1.4 | 2.4 | 4.4 | 6.5 | 19.5 | 27 |
|---|---|---|---|---|---|---|
| Orifice, mm | 23 | 23 | 23 | 23 | 31.75 | 41.28 |
| Orifice, in. | 0.900 | 0.900 | 0.900 | 0.900 | 1.250 | 1.625 |
| Sizes | 3/4 to 2 in. | 3/4 to 2 in. | 3/4 to 2 in. | 3/4 to 2 in. | 1-1/2 and 2 in. | 1-1/2 and 2 in. |
Body dimensions and weights, threaded or socket weld ends
| Size | Face to face A | Standard bonnet height C | EB bonnet height C | Body weight |
|---|---|---|---|---|
| 3/4 in. (20 mm) | 8.24 in. (210 mm) | 5.51 in. (142 mm) | 9.92 in. (249 mm) | 12 kg (27 lb) |
| 1 in. (25 mm) | 8.24 in. (210 mm) | 5.51 in. (142 mm) | 9.92 in. (249 mm) | 12 kg (27 lb) |
| 1-1/2 in. (40 mm) | 9.88 in. (251 mm) | 5.51 in. (140 mm) | 9.92 in. (254 mm) | 16 kg (36 lb) |
| 2 in. (50 mm) | 11.24 in. (286 mm) | 5.51 in. (140 mm) | 9.92 in. (254 mm) | 20 kg (45 lb) |
With a 3-1/2 inch actuator in the 150-450, 150-300 or 400-750 psi ranges the Cv of the Masoneilan 536H is limited to 60 percent of nominal, that is 11.7 instead of 19.5 and 16.2 instead of 27. In the saturated steam table the Cv 6.5 trim passes 638 lb/hr at 50 psig inlet and 30 psig outlet.
Related Masoneilan regulators include the Masoneilan 535H pressure reducing regulator, Masoneilan 535H-536H Series family page and Masoneilan 526 double-seated back pressure regulator.
Request a Quote for Masoneilan 536H
To get a quotation for the Masoneilan 536H, tell the Seven Star LLC instrumentation division the fluid, the upstream pressure to be held, the flow range, body size and end connection. We confirm Cv, actuator and spring range, confirm availability and lead time at quotation, and provide the Masoneilan 536H datasheet and instruction manual from Baker Hughes through this page. Seven Star LLC supplies genuine Masoneilan products across Oman and the GCC.
Masoneilan control valves and actuator series
The globe valve listing centers on the 21000 series, including the cryogenic version with extension bonnet, and the 41005 cage-guided series in high pressure, API 6A and VRT anti-cavitation executions. The 80385 and 80386 are three-way combining and diverting valves. Rotary products include the 35002 Camflex II and the 37002 MiniTork II butterfly control valve. Actuators cover spring-diaphragm, cylinder and rack-and-pinion designs, among them the 5A cylinder actuator for Camflex II. Masoneilan also makes pressure regulators, SVI digital valve positioners and displacer-type level instruments, and offers Lo-dB trim for noise control.Where Masoneilan valves are used
Throttling duty on steam, hydrocarbons, gas and water is the daily work of these valves: feedwater and steam conditioning in power plants, separator and compressor loops in gas processing, high pressure drop letdown, cryogenic service in LNG and air separation, and general flow, pressure and level control in refineries and chemical plants.Ordering Masoneilan valves and spare parts: what we need
For spare parts the serial number is decisive, since the factory record behind it lists trim, materials and actuator. Send a clear nameplate photo with serial number, model number, size and pressure class. For a new valve add the process data: fluid, inlet and outlet pressure, temperature, minimum, normal and maximum flow, required leakage class, fail position, air supply and control signal.Browse Masoneilan products by category: Control Valves, Valve Actuator, Regulators, Valve Positioner, Level Transmitter.
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