Masoneilan 536V Series Back Pressure Microflow Regulator
Overview
The Masoneilan 536V is a direct-operated back pressure regulator from Baker Hughes designed to maintain a uniform upstream pressure at very small flow rates. Baker Hughes describes the 536V as the microflow equivalent of the 526-536 back pressure regulators, with a single-seat microflow body and a simple mechanical spring-diaphragm actuator. Where the larger models offer rated Cv from 1.4 to 27 on the 536H and from 3.6 to 125 on the 526, the Masoneilan 536V covers rated Cv values from 0.004 to 3.8, which suits sample lines, chemical injection skids, pilot plants, analyzer houses and small test rigs where a fraction of a litre per minute must be held at a fixed pressure.
In Oman and the GCC, Seven Star LLC supplies the Masoneilan 536V to refineries, gas plants, laboratories and packaged-system builders in the Sultanate of Oman and across the GCC. Our instrumentation division in Muscat helps customers match the plug and seat ring trim and the spring range to the pressure and flow data, and supplies the Baker Hughes instruction manual with every enquiry so that maintenance teams can plan spares before the regulator arrives.
Back Pressure Operating Principle of the Masoneilan 536V
The Masoneilan 536V controls the pressure upstream of itself. The controlled pressure is piped from a convenient upstream point, six to ten feet (1.8 to 3 m) from the regulator, to a 1/2 inch NPT connection in the diaphragm case, with a gauge and a needle valve in the line. The adjustable spring holds the plug closed, and an increase in controlled pressure above the set point acts on the diaphragm, retracts the actuator stem and lifts the plug off the seat. Baker Hughes calls this an air-to-retract stem actuator. As the upstream pressure falls back the spring pushes the plug down again, so the regulator throttles the outlet flow just enough to hold the set pressure. The needle valve in the sensing line also acts as an adjustable choke that prevents cycling when a pump pulsates.
The set point is chosen by turning the spring adjuster screw, clockwise to compress the spring and raise the pressure, counter-clockwise to lower it. The factory proves each unit over its full range and then fully relieves the spring to avoid stress in the diaphragm and spring during storage, so the manual stresses that the regulator must be adjusted before it is put into service, with the stop valve on the outlet side open and the inlet valve opened slowly while the gauge is watched.
Engineering Design of the Masoneilan 536V
The Masoneilan 536V accepts eight plugs and five seat rings, which combine into ten plug and seat ring assemblies numbered 0 to 9. Trim 0 has a rated Cv of 3.8, and the series steps down through 2.3, 1.2, 0.60, 0.25, 0.10, 0.050, 0.025 and 0.010 to 0.004 at trim 9. The four finest plugs, trims 6 to 9, differ only in the angle of the flat machined on the plug point and share the same seat ring and spacer. For Cv values below 0.10 the seat ring is made in two parts, a seat ring proper and a spacer, and the plug stem carries a retaining ring.
The actuator uses nylon-reinforced neoprene diaphragms, which can be PTFE coated for special service, and a PTFE and Kevlar packing with square-section skive-cut rings. The nominal ranges are 0.5 to 3 psi in an 11 inch case, 2 to 5 psi in a 9 inch case and 3 to 15, 10 to 40, 30 to 85 and 60 to 170 psi in a 5 inch case. A safety pin and packing spacer prevent the plug from being pushed out of the body if the actuator is removed while the line is still pressurised.
Key Features
The following points explain why the Masoneilan 536V is specified for small back pressure duties:
- Ten plug and seat ring trims give rated Cv from 0.004 to 3.8, so even a trickle of fluid can be controlled accurately.
- Six actuator ranges from 0.5-3 psi to 60-170 psi let one body style serve both very low and fairly high set points.
- The air-to-retract actuator is a simple mechanical device that needs no air supply, positioner or power.
- A safety pin and packing spacer retain the plug when the actuator is removed under pressure.
- A quick packing change method is available for trims with Cv 0.6 to 3.8 without disturbing the actuator calibration.
- A separate actuator packing box can be topped up or replaced without dismantling the actuator or the body.
- The manual marks the seat ring, seat ring gasket, retaining ring, diaphragm, O-ring and actuator packing among the recommended spares.
- Baker Hughes estimates the useful life of the Masoneilan 536V at more than 25 years with annual inspection and routine maintenance.
Industrial Applications
The Masoneilan 536V is used wherever a small stream must be held at a constant upstream pressure: back pressure on sample conditioning systems and analyzers, chemical injection and dosing lines, fuel gas and nitrogen purge circuits, and laboratory or pilot units that simulate process pressure. In Oman these applications occur at gas processing plants, refineries and petrochemical complexes, at the water laboratories that support desalination in Muscat and Salalah, and in the instrument workshops and packaged skid factories near Sohar.
In Oman and the GCC, Seven Star LLC supplies the Masoneilan 536V together with its reducing companion and the other Masoneilan regulators, and can quote a matching pressure reducing regulator and the Masoneilan 174 Series regulator where very low pressures must be controlled. The Baker Hughes manual advises a three-valve bypass around the regulator and, on steam service, mounting the diaphragm chamber down so that a water seal protects the diaphragm.
Technical Specifications
The table below collects the Masoneilan 536V datasheet values, taken from the Baker Hughes instruction manual because there is no separate 536V datasheet. Please consult the manual and the 535H/536H/535V technical specification for body ratings and dimensions of the microflow body.
| Parameter | Specification |
|---|---|
| Model | Masoneilan 536V Back Pressure Microflow Regulator |
| Function | Direct-operated back pressure regulator, controlled pressure upstream |
| Body type | Microflow, single seat |
| Actuator | Spring-diaphragm, air-to-retract stem, spring holds the plug closed |
| Nominal actuator ranges | 0.5-3 psi (case 11); 2-5 psi (case 9); 3-15, 10-40, 30-85 and 60-170 psi (case 5) |
| Sensing connection | 1/2 inch NPT in the diaphragm case |
| Trim numbers 0 to 9, rated Cv | 3.8, 2.3, 1.2, 0.60, 0.25, 0.10, 0.050, 0.025, 0.010, 0.004 |
| Seat ring | One piece for Cv 0.10 and above; seat ring plus spacer below Cv 0.10 |
| Seat ring retainer torque | 59 ft-lb (8 daN.m) with stainless-reinforced graphite gasket; 40 ft-lb (5.5 daN.m) with glass-filled PTFE gasket; 15 ft-lb (2 daN.m) on Cv 3.8 |
| Diaphragm | Nylon-reinforced neoprene; PTFE coating on request |
| Actuator packing | PTFE and Kevlar, square section, skive cut |
| Estimated useful life | 25+ years |
Related Masoneilan regulators include the Masoneilan 535V-50 differential microflow regulator, Masoneilan 535V Series microflow regulator and Masoneilan 536H back pressure regulator.
Request a Quote for Masoneilan 536V
To request pricing or technical support for the Masoneilan 536V, send a formal RFQ to the Seven Star LLC instrumentation division with the fluid, the upstream set pressure, the flow range, the body size and the end connection. We confirm the trim number and actuator range, advise on regional warehouse availability and provide the Baker Hughes instruction manual for download from this page. In Oman and the GCC, Seven Star LLC delivers genuine regulators with manufacturer documentation and responsive 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.
Reviews
There are no reviews yet.