Masoneilan 535H-536H Series Single-Seat Pressure Regulator
Overview
The Masoneilan 535H-536H Series from Baker Hughes is a single-seat, high-capacity globe regulator designed to deliver accurate reduced pressure of air, liquids, saturated steam and superheated steam. Model 535H reduces downstream pressure, Model 536H holds upstream pressure as a back pressure regulator, and the -50 options (535H-50 and 536H-50) control differential pressure. Because the valve is single seated, it can be supplied with soft-seat trim for tight shutoff, which is the main practical difference from the double-seated 525-526 family. Body sizes are 3/4, 1, 1-1/2 and 2 inch, and the regulator is operated by the 10900 Series spring-diaphragm actuator.
In Oman and the GCC, Seven Star LLC proudly supplies the Masoneilan 535H-536H Series to industrial users across the Sultanate of Oman and the GCC. We work with process, utilities and maintenance engineers in Muscat to select the correct orifice, seat type, actuator size and spring range, and we provide genuine Masoneilan documentation with every order.
How the Masoneilan 535H-536H Series Controls Pressure
The Masoneilan 535H-536H Series is self-acting: the process pressure itself is the control signal. A control line of 1/2 inch NPT connects the point to be controlled to the diaphragm case of the 10900 actuator, and the diaphragm force opposes an adjustable spring. The manual defines the two main models by where that control point sits. On the 535H, downstream pressure is controlled, so a rise in outlet pressure drives the plug toward the seat and restricts flow. On the 536H, upstream pressure is controlled, so a rise in upstream pressure lifts the plug and passes flow, which is the behaviour needed to hold a vessel or line at a fixed back pressure.
The body of the Masoneilan 535H-536H Series is flow-to-open, and the numbering system identifies the valve mounting as the 21000 body (H) with the plug type defining reducing or back pressure service. For differential service the -50 option places two pressures across the diaphragm. In all cases the manual recommends a gauge and a needle valve in each control line, because the needle valve both isolates the line and works as an adjustable choke that prevents cycling when a pump pulsates, and a three-valve bypass so the regulator can be removed without shutting the system down.
Engineering Design of the Masoneilan 535H-536H Series
The body of the Masoneilan 535H-536H Series is a high-capacity globe with a bolted bonnet, standard or extension, and is available in carbon steel, 316 stainless steel or chrome-molybdenum steel. The plug is a disc type guided at the top with a heavy guide, and the characteristic is quick opening. Seat rings are either threaded or quick change; the 536H is limited to quick-change trim. Trim can be full area or reduced capacity in every size, with orifice diameters from 6.35 mm (0.25 inch) up to 41.28 mm (1.625 inch) giving nominal Cv values of 1.4, 2.4, 4.4, 6.5, 19.5 and 27. Standard trim is 316 stainless steel, with hardfaced 316 stainless steel for severe duty and a PTFE insert plug for soft seating.
On the Masoneilan 535H-536H Series, seat leakage follows the seat type: hard or metal seats meet Class IV, and soft seats meet Class VI, but soft seat is only offered on the 535H and only on regulators with a seat-ring diameter above 20.62 mm. The specification lists a temperature range of -50 F (-46 C) to 446 F (230 C) for these seat leakage classes. For services hotter than the diaphragm can tolerate, the regulator is mounted with the actuator below the body centreline so that a condensate barrier protects the diaphragm. End connections include RF and ring-type-joint flanges in ASME Class 150, 300 and 600 as well as ISO and DIN PN ratings, plus socket weld and threaded ends in all sizes.
Key Features
The main strengths of the Masoneilan 535H-536H Series for pressure control duty are summarised below:
- Single-seat construction allows soft-seat trim with Class VI shutoff on the 535H, where a double-seated body cannot be tight.
- Four functions are covered by one platform: pressure reducing, differential pressure reducing, back pressure and differential back pressure.
- Six orifice sizes give nominal Cv values from 1.4 to 27, so the regulator can be matched closely to the real flow.
- A heavy top-guided disc plug gives stable positioning, and threaded or quick-change seat rings make maintenance practical.
- Carbon steel, 316 stainless steel and chrome-molybdenum bodies cover general, corrosive and higher-temperature services.
- The optional extension bonnet and condensate barrier mounting arrangement protect the diaphragm in hot steam.
- Spring-diaphragm actuators cover ranges from 0.5 psi up to 750 psi, with high-pressure differential versions rated to 1,500 psi static.
- The manual gives an estimated useful life of 25 years or more with annual inspection and routine maintenance.
Industrial Applications
The Masoneilan 535H-536H Series is a good fit for compact steam and fluid systems where flows are small to moderate and tight shutoff matters. Typical duties for the Masoneilan 535H-536H Series include reducing steam from a distribution header to a heat exchanger, sterilisation or tracing system, regulating compressed air or gas to a skid, holding back pressure on a sample or recirculation line, and controlling water pressure on pump discharge. Facilities of this type in Oman include hospital and hospitality complexes in Muscat, pharmaceutical and food plants, desalination and district cooling utilities, and light industry in the Sohar and Salalah economic zones.
In Oman and the GCC, Seven Star LLC supplies the Masoneilan 535H-536H Series and the matching 21000 Series parts, including the Masoneilan 21000 Series seal kit. Where the flow is even smaller, the micro-flow Masoneilan 28000 Series Varipak valve body is the basis of the 535V regulator, and for fixed direct-operated duty we also supply the Masoneilan 172 Series regulator. Our team can compare these options with the Masoneilan 535H-536H Series against your pressure and flow data.
Technical Specifications
The table below summarises the main Masoneilan 535H-536H Series datasheet data from the Baker Hughes technical specification. Capacity tables for steam, air and water, and full dimensions, are in the official datasheet.
| Parameter | Specification |
|---|---|
| Model | Masoneilan 535H (pressure reducing), 535H-50 (differential pressure reducing), 536H (back pressure), 536H-50 (differential back pressure) |
| Service | Steam, gas, liquids |
| Body | High-capacity globe, single seat, flow to open |
| Sizes | 3/4, 1, 1-1/2, 2 inch (20, 25, 40, 50 mm) |
| Body and bonnet material | Carbon steel, 316 stainless steel, chrome-molybdenum steel |
| End connections | Flanged ASME Class 150, 300, 600 (RF and RTJ), ISO and DIN PN ratings, socket weld, threaded |
| Trim | Disc plug, threaded or quick-change seat ring, heavy top guide, full area or reduced capacity |
| Characteristic | Quick opening |
| Nominal Cv | 1.4, 2.4, 4.4, 6.5, 19.5, 27 (sizes 1-1/2 and 2 inch for the two largest) |
| Seat leakage | Class IV (hard seat), Class VI (soft seat, 535H only) |
| Actuator | 10900 Series spring-diaphragm |
Face-to-face dimension and body weight by size
| Size | Face to face, Class 150 RF (mm) | Body sub-assembly weight, threaded or socket weld / Class 150 flanged (kg) |
|---|---|---|
| 3/4 inch (20 mm) | 184 | 12 / 16 |
| 1 inch (25 mm) | 184 | 12 / 16 |
| 1-1/2 inch (40 mm) | 222 | 16 / 22 |
| 2 inch (50 mm) | 254 | 20 / 26 |
Single-model pages for this family are the Masoneilan 535H pressure reducing regulator and Masoneilan 536H back pressure regulator.
Related Masoneilan pressure regulators include the Masoneilan 525-526 Series double-seated regulator, Masoneilan 535V Series microflow regulator and Masoneilan 173 Series back pressure regulator.
Request a Quote for Masoneilan 535H-536H Series
To request pricing or technical support for the Masoneilan 535H-536H Series, send a formal RFQ to the Seven Star LLC instrumentation division stating the fluid, set pressure, flow, inlet pressure and desired shutoff class. We confirm orifice, trim and actuator range, advise on regional warehouse availability and supply the Baker Hughes technical datasheet from this page. In Oman and the GCC, Seven Star LLC delivers genuine products with manufacturer documentation and local support.
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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