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Brand: Masoneilan
Masoneilan Type 87/88 Camflex Spring-Diaphragm Actuator Diaphragm
Description
Overview
The Masoneilan Type 87/88 spring-diaphragm is the standard replacement actuation membrane fitted to the pneumatic actuators used across Masoneilan Camflex rotary control valve installations, providing the same proven pressure-to-force conversion technology found on Masoneilan globe-valve actuators but adapted to drive the Camflex eccentric-plug rotary mechanism through its rated angular stroke. Camflex valves are prized in the field for their compact, high-rangeability rotary design, and keeping the spring-diaphragm actuator that drives them in good condition is what preserves the tight shutoff and accurate throttling performance that makes the Camflex platform attractive in the first place.
With fast quotation turnaround and technical support, Seven Star LLC supplies genuine Masoneilan Camflex Type 87/88 spring-diaphragm actuator spares to process plants, EPC contractors, and valve workshops across Oman and the GCC.Seven Star LLC supplies this item on request with the manufacturer documentation, and availability and lead time are confirmed at quotation.
Operating Principle
On a Masoneilan Camflex spring-diaphragm actuator, regulated instrument air from the positioner enters the actuator casing and acts across the diaphragm’s effective area, generating a linear pneumatic force exactly as it would on a conventional globe-valve actuator. That linear force is then converted, through the actuator’s yoke and lever linkage, into the rotational torque needed to sweep the Camflex valve’s eccentric plug through its arc of travel, seating it against the valve body at one extreme of stroke and lifting it clear of the seat at the other. The diaphragm therefore remains the single component responsible for translating air pressure into usable actuator force, even though the valve it ultimately drives moves rotationally rather than in a straight line.
Because Masoneilan Camflex valves are frequently selected for tight-shutoff, high-rangeability duty, the practical consequence of a degraded diaphragm is more visible than on some other actuator types: any loss of effective sealing area or flex-fatigue in the diaphragm shows up directly as reduced seating force at the closed position, which can compromise the bubble-tight shutoff Camflex valves are chosen for in the first place. Replacing the spring-diaphragm proactively, in line with the manufacturer’s recommended service interval, protects both the actuator’s stroke accuracy and the valve’s shutoff integrity.
Engineering Design of the Masoneilan Camflex Actuator Diaphragm
Physically, the diaphragm used on Masoneilan Camflex Type 87/88 actuators shares the same fabric-reinforced elastomer construction, molded rolling convolution, and reinforced center hub found across the standard Type 87/88 globe-actuator range, but is supplied to the specific bolt pattern, outer diameter, and convolution depth matching the actuator size fitted to your particular Camflex valve. The correct casing interface is essential on a rotary actuator installation because the diaphragm plate connects through the yoke lever mechanism rather than a simple straight stem, so a dimensionally incorrect diaphragm can introduce lever misalignment as well as an air leak.
Replacement follows the same general procedure used across the Type 87/88 family – releasing the actuator casing bolts with spring pre-load safely relieved, withdrawing the old diaphragm, fitting the correctly sized replacement with its convolution oriented per the Camflex actuator instruction manual, and re-torquing the casing evenly to achieve a leak-free seal – while paying particular attention to the yoke lever alignment during reassembly, since the rotary linkage geometry is more sensitive to reassembly accuracy than a straight-stem globe actuator.
Key Features
Genuine Masoneilan Camflex Type 87/88 spring-diaphragm spares give maintenance teams a reliable path back to full valve performance:
- Fabric-reinforced elastomer construction resists flex-fatigue cracking across sustained rotary-actuator stroke cycles.
- Diaphragm and convolution dimensions are matched to the exact Camflex actuator size and spring range on your valve.
- Preserves the tight-shutoff seating force that makes the Camflex eccentric-plug design valuable in throttling and isolation service.
- Elastomer compound resists ozone, UV, and the temperature extremes typical of outdoor installations across Oman and the GCC.
- Reinforced center hub maintains correct alignment through the actuator’s yoke and lever linkage during every stroke.
- Genuine Baker Hughes manufacturing traceability ensures form, fit, and function identical to the original actuator specification.
- Standard actuator-casing replacement procedure keeps downtime confined to a single planned maintenance window.
- Available across the full range of Masoneilan Camflex Type 87/88 actuator sizes used in Masoneilan rotary control valve installations.
Industrial Applications
The Masoneilan Camflex platform, fitted with Type 87/88 spring-diaphragm actuators are widely used across Oman’s oil and gas gathering stations, refinery process units, and utility systems where a compact, high-rangeability rotary valve is preferred over a larger globe-valve installation, as well as in district cooling and desalination plants across Muscat, Sohar, and Salalah where space constraints and tight shutoff requirements both favor the Camflex design. Facility engineers maintaining these installations rely on genuine spring-diaphragm replacements to keep the valve’s shutoff and throttling performance within its original specification over years of service.
With engineering support in Muscat, Seven Star LLC supplies Type 87/88 spring-diaphragm spares for Camflex actuators to EPC contractors, valve repair workshops, and plant maintenance departments throughout the Sohar and Salalah economic zones and across the broader GCC, confirming the exact actuator size and spring range against your nameplate or drawing before ordering so the correct diaphragm reaches site the first time.
Technical Specifications
The table below summarizes the key characteristics of the Masoneilan Camflex Type 87/88 actuator diaphragm family; exact dimensions are confirmed against your specific actuator size at order time:
| Parameter | Specification |
|---|---|
| Model | Type 87/88 Camflex-compatible spring-diaphragm (size confirmed per actuator nameplate) |
| Compatible Valve Platform | Masoneilan Camflex eccentric-plug rotary control valve |
| Actuator Type | Spring-diaphragm (linear force converted to rotary stroke via yoke and lever) |
| Component Type | Spring-diaphragm (pneumatic actuator spare part) |
| Construction | Fabric-reinforced elastomer disc, molded rolling convolution |
| Function | Converts instrument air pressure into actuator force for Camflex rotary stroke |
| Manufacturer | Masoneilan, a Baker Hughes brand |
| Sourcing | OEM part – supply, confirmed to actuator nameplate |
Request a Quote for Masoneilan Type 87/88 Camflex Spring-Diaphragm Actuator Diaphragm
Maintaining a Masoneilan Camflex rotary valve installation? Contact Seven Star LLC instrumentation division for a formal RFQ on the correct Masoneilan Type 87/88 spring-diaphragm for your Camflex actuator size, confirm current availability and lead time, or request the technical datasheet for your maintenance files. Backed by manufacturer datasheet documentation, Seven Star LLC backs every shipment with genuine parts, correct-fit verification against your actuator nameplate, and manufacturer-supported technical guidance.
Browse the full Masoneilan range or see more Valve Actuator products supplied by Seven Star LLC in Oman and the GCC.
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About brand
Masoneilan is a control valve brand of Baker Hughes with roots going back to 1882. Its Camflex eccentric plug rotary valve, 21000 series globe valve and SVI digital positioners are fixtures in refineries, gas plants and power stations. Every valve carries a serial number and a long model number that define the actuator, body and trim.
Seven Star LLC is an independent supplier listing Masoneilan control valves, actuators, regulators, positioners and level instruments for buyers in Oman and the GCC. We source complete valves as well as Masoneilan spare parts against that nameplate data.
Masoneilan at a glance
| Origin | Mason Regulator Company, Boston area, USA (1882). It acquired the Neilan Company of California in 1931, and the two names became Masoneilan. |
|---|---|
| Ownership | Dresser Industries from 1985, then GE Oil & Gas, now Baker Hughes |
| Milestones the company cites | Cv flow coefficient introduced (1944), spring-diaphragm actuators (1955), Camflex rotary globe valve (1968), Lo-dB low-noise trim (1975), LincolnLog axial-flow letdown valve (1982), Varipak (1984), V-Log (1998), SteamForm steam conditioning valve (2002) |
| Product families | Globe, rotary, butterfly and severe-service control valves, actuators, digital positioners, self-operated regulators and displacer level instruments |
| Typical duty | Throttling control of steam, gas, hydrocarbons and water, high-pressure letdown, anti-cavitation and low-noise service |
Masoneilan control valves and actuator series
| Series | Type | Typical use |
|---|---|---|
| 21000, 21009 | Top-guided and cage-guided globe valves | General process control. Cryogenic (21000 C), bellows seal (21000 BS) and API 6A versions are also made |
| 41005 | Cage-guided globe valve | Higher pressure drop and larger sizes, up to 30-36 inch extended sizes; VRT anti-cavitation and API 6A versions |
| 35002 Camflex II | Eccentric plug rotary control valve | Erosive, flashing and dirty service; HC high capacity, DVD low noise and GR globe replacement versions |
| 37002 MiniTork II, 39003/39005, 33000 | Butterfly control valves, high-performance and triple-offset | Large flows at low pressure drop, and tight-shutoff duty |
| 28000 Varipak | Microflow control valve | Very small flows, with adjustable Cv |
| 78400/18400 LincolnLog, 77000, 49000 V-Log | Severe-service multi-stage valves | High-pressure liquid letdown, anti-cavitation and gas noise reduction |
| 84000/84003 SteamForm, DSH | Steam conditioning valves and desuperheaters | Turbine bypass and steam pressure and temperature reduction |
| 87/88, 37/38, 51/52/53 | Spring-diaphragm and piston actuators | Linear and rotary valve actuation; diaphragms and soft-goods kits are listed separately |
| SVI3, SVI II AP, SVi1000, SVI FF | Digital valve positioners | HART or FOUNDATION Fieldbus positioning with valve diagnostics; the SVI II ESD adds partial stroke testing |
| 4700/4800, 8013 | Pneumatic and electro-pneumatic positioners | Older installed base. Many sites move to SVI positioners at overhaul |
| 525/526, 535/536, 171-174 | Self-operated pressure regulators | Pressure reducing and back-pressure control without external power |
| 12400, 12800 | Displacer level transmitters and controllers | Digital (12400, HART, SIL 2 version 12420) and pneumatic (12800) level control on separators and vessels |
Where Masoneilan valves are used
Throttling duty on steam, hydrocarbons, gas and water is the daily work of these valves. Typical services are 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 decides the order, because the factory record behind it lists the trim, materials and actuator. Send a clear nameplate photo with the 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. When an older positioner or valve series is no longer made, we quote the successor that Baker Hughes names and list the mounting kit it needs.
Frequently requested Masoneilan models: Masoneilan 4700E/4800E Electropneumatic Valve Positioner, Masoneilan 28000 Series VariPak Valve Seal & O-Ring Kit, Masoneilan 535H Single-Seat Pressure Reducing Regulator.
Facts checked against Baker Hughes Masoneilan product information and the company's published timeline, October 2026.
Browse Masoneilan products by category: Control Valves, Valve Actuator, Regulators, Valve Positioner, Level Transmitter.
FAQ
Questions about the Masoneilan Type 87/88 Camflex Spring-Diaphragm
Answers from our engineering team on installation, compatibility and integration.
01What is this diaphragm used for on a Camflex valve?
It is the genuine Masoneilan Type 87/88 spring-diaphragm that converts regulated instrument air pressure into the actuator force driving the Camflex eccentric-plug rotary valve through its stroke via the actuator yoke and lever linkage.
02Does this part carry a single fixed part number?
No. Camflex actuators are specified by valve size and spring range, so the correct diaphragm dimensions vary by installation; Seven Star LLC confirms the exact match against your actuator nameplate or drawing before dispatch.
03How does replacing this diaphragm affect valve shutoff?
A fresh, correctly fitted diaphragm restores the actuator seating force to specification, which directly supports the tight, bubble-tight shutoff that Camflex eccentric-plug valves are selected for.
04Can Seven Star LLC identify the right diaphragm from an old or unclear part tag?
Yes, our instrumentation division cross-references legacy Camflex actuator tags, drawing numbers, and valve nameplates against current Masoneilan records to confirm the correct replacement before shipping.
05Is Seven Star LLC an experienced supply partner for Masoneilan products?
Yes, Seven Star LLC supplies Masoneilan products to customers in Oman and the GCC and can provide the manufacturer documentation and technical support on request.


















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