Masoneilan 173 Series Self-Contained Back Pressure Regulator
Overview
The Masoneilan 173 Series is a spring-loaded, direct-operated pressure relieving or back pressure regulator for continuous service on steam, gas and liquid. It is the upstream-pressure member of the compact Masoneilan self-contained regulator range: where the 172 Series reduces pressure at its outlet, the 173 Series holds pressure at its inlet by passing flow only when that pressure rises above the set point. Baker Hughes lists body sizes from 1/2 to 2 inch (DN15 to DN50), a wide set of end connections, and a design intended for rugged, continuous industrial use with years of reliable service.
In Oman and the GCC, Seven Star LLC proudly supplies the Masoneilan 173 Series to operators, skid builders and maintenance contractors in the Sultanate of Oman and across the GCC. Our instrumentation division in Muscat helps customers choose the Masoneilan 173 Series trim number, actuator size, spring and diaphragm material that match their set pressure and fluid, and provides genuine Masoneilan documentation with each order.
Working Principle of the Masoneilan 173 Series
The Masoneilan 173 Series needs no external power, air or signal. Upstream pressure is sensed internally, with external sensing available on request, and it acts on the diaphragm against a calibrated spring. When the pressure stays at or below the set point the spring keeps the plug on the seat. When it rises above the set point the diaphragm force overcomes the spring, lifts the plug and passes flow, which relieves the excess and brings the pressure back to the set value. The regulator is a flow-to-close design, a design in which the direction of process flow acts to close the plug.
On the Masoneilan 173 Series, the set point is chosen by the actuator size and spring combination. The tech spec lists a standard set point range from 0.017 to 667 psig (0.0012 to 46.0 barg) across actuator sizes 100, 120, 130, 140, 220, 360 and 515. The numbering system encodes the other key choices: the first digit after the series selects relieving with a metal seat or a soft seat, the second selects a metal or elastomeric diaphragm, and the final digits select the trim size, from 01 for very small flows to 45 for the largest.
Engineering Design of the Masoneilan 173 Series
The Masoneilan 173 Series uses a disc-type trim plug on an integral seat, with stainless steel trim as standard and other materials on request. Bodies are available in carbon steel, 316 stainless steel and alloys, with the tech spec noting special constructions in LCB, WCC (NACE), 316L, 317, duplex, super duplex, Monel and Hastelloy B or C. Threaded NPT, GAS or BSP connections and flanged ASME Class 150, 300 and 600 connections are offered, with an ISA face-to-face option, and standard face-to-face lengths run from 184 mm to 254 mm for Class 150 flanged bodies.
The actuator offers an elastomeric or metal diaphragm. Elastomer choices include polychloroprene, EPDM and FKM, and the tech spec gives their temperature windows, for example EPDM from -35 C to 150 C and an AISI 316 diaphragm from -196 C to 455 C for steam service. A fully sealed construction that is ATEX compliant is available for dangerous media, an optional handwheel variant exists, and the maintenance design allows service of the trim while the body stays in the line.
Key Features
These characteristics make the Masoneilan 173 Series well suited to simple, dependable back pressure control:
- Spring-loaded, direct-operated design needs no instrument air, power or control signal.
- Flow-to-close construction is specified by Baker Hughes for this regulator family.
- Five to nine different Cv values per body size let the regulator be matched closely to the required capacity and accuracy.
- Metal-seat or soft-seat versions allow a choice between high-temperature robustness and tighter sealing.
- Internal pressure sensing is standard, with external sensing available when the piping layout requires it.
- Elastomeric or metal diaphragms cover temperatures from -196 C to 455 C depending on material.
- A fully sealed, ATEX-compliant construction is available for dangerous media applications.
- In-line maintenance and rugged construction keep downtime low over the life of the regulator.
Industrial Applications
Typical duties for the Masoneilan 173 Series include holding minimum pressure on a pump recirculation or sample line, maintaining a steady pressure in a gas blanketing or fuel gas header, venting excess pressure from steam and condensate lines, and protecting a downstream process by keeping a defined pressure on a skid. Its compact body and inlet-pressure sensing suit packaged skids, and the sealed version is intended for dangerous media.
In Oman and the wider GCC, these needs arise in oil and gas facilities, gas processing, refinery utilities, chemical dosing skids, desalination plants and district cooling plant rooms in Muscat, Sohar and Salalah. In Oman and the GCC, Seven Star LLC supplies the Masoneilan 173 Series alongside the Masoneilan 172 Series pressure reducing regulator, the Masoneilan 174 Series regulator and the Masoneilan 10000 Series double port valve, and can advise on the right match for each service.
Technical Specifications
The table below summarises the main data of the Masoneilan 173 Series from the Baker Hughes technical specification. Spring and set pressure tables, temperature limits and weights are in the official datasheet.
| Parameter | Specification |
|---|---|
| Model | Masoneilan 173 Series self-contained back pressure (pressure relieving) regulator |
| Service | Steam, gas, liquids |
| Sizes | 1/2, 3/4, 1, 1-1/2, 2 inch (DN15, DN20, DN25, DN40, DN50) |
| End connections | Threaded NPT-F, GAS-F or BSP-F; flanged ASME Class 150, 300, 600 and PN 16/25/40 |
| Body material | Carbon steel, stainless steel, other alloys on request |
| Trim | Disc plug, integral seat, stainless steel standard; metal or soft seat |
| Capacity | Trim numbers 01 to 45; rated Cv from 0.031 up to 35 on the 2 inch body (28 with the size 100 actuator), per technical specification Table 4 |
| Set point range | 0.017 to 667 psig (0.0012 to 46.0 barg) |
| Diaphragm | Polychloroprene, EPDM, FKM or AISI 316 metal |
| Pressure sensing | Internal; external on request |
| Actuator sizes | 100, 120, 130, 140, 220, 360, 515 |
Face-to-face dimension by body size
| Size | Class 150 RF (mm) | Class 300 RF (mm) | Class 600 RF (mm) | Threaded (mm) |
|---|---|---|---|---|
| 1/2 inch (DN15) | 184 | 190 | 203 | 130 |
| 1 inch (DN25) | 184 | 197 | 210 | 130 |
| 1-1/2 inch (DN40) | 222 | 235 | 251 | 170 |
| 2 inch (DN50) | 254 | 267 | 286 | 170 |
Related Masoneilan pressure regulators include the Masoneilan 525-526 Series double-seated regulator, Masoneilan 535H-536H Series single-seat regulator and Masoneilan 535V Series microflow regulator.
Request a Quote for Masoneilan 173 Series
To request pricing or technical support for the Masoneilan 173 Series, send a formal RFQ to the Seven Star LLC instrumentation division with your fluid, set pressure, flow, temperature and connection details. We confirm trim, diaphragm and spring against your data, 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.
- Datasheet Masoneilan 173 Series Technical Specifications Datasheet Download
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