Brand: Masoneilan

Masoneilan 720050-177-999 Type 87/88 Size 10 Actuator Spare Parts Kit

Name: Masoneilan 720050-177-999 Actuator Kit – Datasheet & Quote
Brand: Masoneilan

Description

Overview

Masoneilan 720050-177-999 is a genuine Size 10 actuator soft-parts rebuild kit engineered for the Masoneilan Type 87/88 Series pneumatic spring-diaphragm actuator, one of the most widely deployed actuator platforms across Baker Hughes’ Masoneilan control valve range. The Masoneilan 720050-177-999 kit bundles the Buna-N diaphragm, actuator casing O-rings, wiper seals, and the safety labels and washers needed to fully reseal a Size 10 actuator in a single maintenance pass, giving instrumentation technicians every wearing component matched to the correct dimensional and material specification instead of sourcing soft goods piecemeal from generic suppliers.

With fast quotation turnaround and technical support, Seven Star LLC proudly supplies the Masoneilan 720050-177-999 rebuild kit to refineries, gas plants, and utility operators across Oman and the wider GCC. Every kit shipped through Seven Star LLC is matched to Masoneilan part numbers, ensuring correct elastomer compound, verified batch traceability, and full compatibility with the Size 10 actuator housing — a critical assurance for plant reliability teams in Oman’s upstream and downstream facilities where an incorrectly specified diaphragm can force an unplanned shutdown.

Working Principle

The Type 87 (direct, air to extend stem) and Type 88 (reverse, air to retract stem) are spring-opposed pneumatic diaphragm actuators: regulated instrument air loads one face of the diaphragm inside the actuator casing, and the resulting force acts against a calibrated spring pack to produce linear stem travel proportional to the applied signal pressure. The diaphragm supplied in the Masoneilan 720050-177-999 kit is the single component that converts pneumatic pressure into usable mechanical force, so its material condition directly determines actuator repeatability, dead-band, and response speed. A cracked, permanently set, or chemically degraded diaphragm bleeds air across its face, causing the positioner to hunt and the valve to drift off its intended position under otherwise stable process conditions.

Because the diaphragm and its associated casing O-rings are the actuator’s only dynamic sealing elements, replacing them on a fixed maintenance interval — rather than waiting for visible failure — is standard turnaround practice on Masoneilan-equipped control loops. Rebuilding a Size 10 actuator with the correct Masoneilan 720050-177-999 kit restores the actuator’s original spring-to-air force balance, eliminates hysteresis introduced by a hardened diaphragm, and returns the loop to its as-commissioned dead-band without the cost and lead time of a full actuator exchange.

Engineering Design of the Masoneilan 720050-177-999

The Masoneilan 720050-177-999 kit is built around a Buna-N (NBR) diaphragm rated for standard-temperature service from -30°C to 83°C, matched dimensionally to the Size 10 actuator casing bolt circle and center-post configuration used on Type 87 and Type 88 actuators. The diaphragm’s convoluted profile is molded, not cut, preserving the flex geometry that gives the seal its rated fatigue life across repeated full-stroke cycles rather than the shortened service life typical of generic aftermarket substitutes.

Alongside the diaphragm, the kit includes the actuator casing O-rings, wiper seals, and the washers, safety labels and other small parts needed to complete a compliant rebuild of the Size 10 actuator body during a scheduled turnaround. All soft parts are supplied together in a single traceable pack so a technician performing a bench rebuild has every wearing component on hand in one pass, reducing repeat disassembly and the risk of reusing a degraded seal because a replacement wasn’t immediately available in the parts store.

Key Features

The Masoneilan 720050-177-999 kit is specified by instrumentation teams for the following reasons:

Genuine Masoneilan-specification Buna-N diaphragm dimensioned precisely for the Size 10 Type 87/88 actuator casing, eliminating fitment guesswork common with generic replacements.
Standard-temperature elastomer rating of -30°C to 83°C covers the vast majority of onshore process and utility air-loop applications in the GCC.
Complete soft-parts set — diaphragm, O-rings, and wiper seals — supplied together so a single kit closes out an entire Size 10 actuator rebuild.
Compatible across the Type 87 and Type 88 actuator families sharing the Size 10 casing, simplifying spares standardization for sites running mixed valve populations.
Restores original spring-to-diaphragm force balance, correcting positioner hunting and stroke drift caused by a fatigued original diaphragm.
Batch-traceable elastomer sourcing through the genuine Masoneilan supply chain, supporting QA/QC documentation requirements on regulated process units.
Reduces actuator rebuild turnaround time versus sourcing individual soft parts from multiple suppliers.

Industrial Applications

Size 10 Type 87/88 actuators rebuilt with the Masoneilan 720050-177-999 kit are found across Oman’s oil and gas gathering stations, gas processing plants, and refinery control valve populations, as well as on smaller globe and 3-way control valves regulating cooling water, steam, and utility air in district cooling and desalination plants across Muscat, Sohar, and Salalah. Facility teams scheduling turnaround maintenance standardize on the genuine Masoneilan 720050-177-999 kit to avoid the repeat failures associated with generic diaphragm substitutes that do not match the original elastomer specification or convolution geometry.

With engineering support in Muscat, Seven Star LLC supplies the Masoneilan 720050-177-999 kit and the full range of Type 87/88 soft-parts kits to instrumentation contractors, EPCs, and plant maintenance departments throughout the Sultanate of Oman and the GCC, with lead time confirmed at quotation for planned and emergency actuator rebuilds.

Technical Specifications

The Masoneilan 720050-177-999 specification table below summarizes the key parameters of this Size 10 actuator kit:

Parameter	Specification
Model / Part Number	720050-177-999-0000
Compatible Actuator	Masoneilan Type 87/88 Pneumatic Spring-Diaphragm Actuator
Actuator Size	Size 10
Diaphragm Material	Buna-N (NBR)
Temperature Rating	-30°C to 83°C (Standard Temp)
Kit Contents	Diaphragm, actuator O-rings, wiper seals, safety labels, washers and other small parts (per the Baker Hughes Actuator Rebuild Kits fact sheet)
Compatible Valve Series	Masoneilan globe and 3-way control valves fitted with Size 10 actuators
Manufacturer	Masoneilan (Baker Hughes)
Supply Status	New, genuine Masoneilan part

Request a Quote for Masoneilan 720050-177-999 Type 87/88 Size 10 Actuator Spare Parts Kit

Seven Star LLC accepts formal RFQs for the Masoneilan 720050-177-999 Size 10 actuator spare parts kit from procurement teams, EPC contractors, and plant maintenance departments across Oman and the GCC. With manufacturer documentation, Seven Star LLC sources kits on request to support both planned turnarounds and breakdown maintenance, and can supply the full Type 87/88 technical datasheet on request. Contact the Seven Star LLC instrumentation division to confirm actuator compatibility, request current lead time, or submit a formal quotation request for the Masoneilan 720050-177-999 kit or any other genuine Masoneilan rebuild kit.

Other Models in the Masoneilan Type 87/88 Actuator Parts Range

Seven Star LLC supplies models from the Masoneilan Type 87/88 Actuator Parts range in Oman and the GCC. Compare the related models below and request a quote for the one that matches your application.

Model	Category
Masoneilan 010864-003-779 Type 87/88 Size 6 Diaphragm	Valve Actuators	View details
Masoneilan 010865-003-779 Type 87/88 Size 10 Diaphragm	Valve Actuators	View details
Masoneilan 010866003-779-0000 Type 87/88 Size 16 Diaphragm	Valve Actuators	View details
Masoneilan 010867003-779-0000 Type 87/88 Size 23 Diaphragm	Valve Actuators	View details
Masoneilan 720050-177-999 Type 87/88 Size 10 Actuator Spare Parts Kit	Valve Actuators	You are viewing this model
Masoneilan 720050-179-999 Type 87/88 Size 16 Actuator Spare Parts Kit	Valve Actuators	View details

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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.

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.

Frequently Asked Questions

What does the Masoneilan 720050-177-999 kit include?

The kit includes the Buna-N diaphragm, actuator casing O-rings, wiper seals, safety labels, washers and other small parts required to fully reseal a Size 10 Masoneilan Type 87/88 pneumatic spring-diaphragm actuator in a single rebuild pass.

How much does rebuilding with this kit save versus a full actuator replacement?

A soft-parts rebuild using the 720050-177-999 kit typically restores actuator performance for a fraction of the cost and lead time of a complete actuator exchange, and can usually be completed during a scheduled turnaround without removing the actuator from site.

Which Masoneilan actuators and valves is this kit compatible with?

This kit fits the Size 10 casing used on Masoneilan Type 87 and Type 88 pneumatic spring-diaphragm actuators, which are fitted to Masoneilan globe and 3-way control valves across the Masoneilan control valve range.

Is a high or low temperature version of this kit available?

Yes. Alongside the standard-temperature Buna-N version rated -30°C to 83°C, Masoneilan also produces low and high temperature Size 10 kits using alternate elastomer compounds for -50°C to 100°C service; Seven Star LLC can advise and supply the correct variant for your application.

Is Seven Star LLC an experienced supply partner for Masoneilan products?

Yes, Seven Star LLC is an experienced supplier of Masoneilan in Oman and the GCC, supplying genuine actuators, control valves, and rebuild kits with full traceability and local technical support.

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