Masoneilan 37/38 Soft Goods Kits for Spring-Diaphragm Actuators

Overview

Three Masoneilan 37/38 soft goods kits appear in the Baker Hughes Actuator Rebuild Kits fact sheet under the heading “#37/#38 Actuator Soft Goods Kits”: 720033241-999-0000 for size 15, 720033242-999-0000 for size 18 described as “Single Bolting Diaphragm”, and 720033243-999-0000 for size 18 described as “Double Bolting Diaphragm”. The Type 37 (air to close) and Type 38 (air to open) pneumatic spring-diaphragm actuators are the older, lighter sibling of the 87/88 series and remain installed on many Masoneilan globe valves.

Seven Star LLC supplies the Masoneilan 37/38 soft goods kits to maintenance teams throughout Oman and the GCC. Because the fact sheet distinguishes two diaphragm bolting styles for size 18, correct identification before ordering matters more here than on most kits.

Masoneilan 37/38 Soft Goods Kits: Part Numbers Published by Baker Hughes

The fact sheet does not define single versus double bolting. Compare the bolt arrangement of the diaphragm in the actuator with the original, or give us the serial number so we can raise the question with Baker Hughes before you buy.

Size 15 and Size 18 Data for the Masoneilan 37/38 Soft Goods Kits

The 37/38 technical specification (Rev. C, 09/2023) lists these figures for the two sizes the Masoneilan 37/38 soft goods kits serve.

Travel times are bench values with a 3-15 psi range and 20 psi supply; add 15 percent for 6-30 psi. The standard temperature range is −30°C to +80°C (−22°F to +176°F).

Recommended Spares in the Masoneilan 37/38 Soft Goods Kits

The 37/38 instruction manual marks four recommended spares: the packing-box gasket (item 15), the gasket between lower case and yoke (19), the packing (32) and the diaphragm (39). The diaphragm is a molded elastomer with a fabric insert, the packing rings are square-section carbon core with a braided PTFE jacket, the lower-case gasket is acrylic fibre and the packing-box gasket is copper. The materials table in the technical specification shows that the Type 37 parts list contains only the diaphragm from this group, while the Type 38 list adds the packing box, packing and both gaskets. Baker Hughes publishes no bill of materials per kit number, so confirm with us what each kit contains for your actuator type.

Fitting the Masoneilan 37/38 Soft Goods Kits

On a Type 37 the manual says to relieve all spring compression with the spring adjuster (36) before removing the cap screws (45), so the upper case cannot pop up. The nut (30) and washer (41) then release the diaphragm (39). On a Type 38 the whole upper case assembly, including spring barrel, spring and diaphragm plate, must come off because the diaphragm is mounted inverted. Afterwards, supply air through a regulator to the 1/4 in. NPT port and adjust the spring so the stem just begins to move at the minimum pressure on the serial plate, with no air on the diaphragm during adjustment. Packing can be renewed without dismantling the valve, and over-tightening the packing nut causes friction and sluggish response, so on a Type 38 renew the packing at the same time as the diaphragm.

On a 3-15 psi nominal range the stem should start to stroke at 3 psi and finish at 15 psi, plus or minus 5 percent, and the serial plate states the spring range and maximum supply. The manual prefers the molded diaphragm supplied by Baker Hughes and accepts one cut from flat sheet only as an emergency measure up to No. 15 actuators, which is a further reason to buy a kit.

Planning a Rebuild with the Masoneilan 37/38 Soft Goods Kits

The fact sheet recommends new soft goods every time an actuator is repaired or serviced, and says its kits bring a worn actuator back to as-new condition. It also asks four questions about the accessories: the condition of the air set, whether the positioner is up to date, whether the positioner mounting kit moves freely and whether the tubing is damaged or blocking air flow. A corroded mounting kit is named as one of the most frequent causes of a poorly performing positioner.

Key Features

• Masoneilan 37/38 soft goods kits for actuator sizes 15 and 18
• Separate kit numbers for single and double bolting diaphragms on size 18
• Suited to Type 37 air-to-close and Type 38 air-to-open actuators
• Maximum supply 60 psi, standard range −30°C to +80°C
• Quoted against the actuator serial number and bolting style

Industrial Applications

Type 37/38 actuators are fitted to older Masoneilan globe valves in refineries, gas plants, power stations and water treatment works across the GCC. The Masoneilan 37/38 soft goods kits let a maintenance team renew the diaphragm, gaskets and packing without replacing the actuator. Side-mounted handwheel types 6A1, 6A2, 6A3 and 8A and case-mounted types are listed for the family, so tell us whether one is fitted. Related diaphragm-only items include the 010271-016-686 size 9 diaphragm, and the whole spring-diaphragm line is on the Type 87/88 actuator page. A positioner is often replaced at the same time: see the SVI FF positioner.

Also listed: the 010273010-686-0000 size 13 diaphragm and Masoneilan Type 37/38 actuator.

Technical Specifications

The table lists the data Baker Hughes publishes for the Masoneilan 37/38 soft goods kits.

Request a Quote for Masoneilan 37/38 soft goods kits

Send Seven Star LLC an RFQ for the Masoneilan 37/38 soft goods kits with the actuator type (37 or 38), case size, serial number, diaphragm bolting style and quantity. In Oman and the GCC, we confirm the kit number, check delivery to your plant and supply the Baker Hughes documents linked on this page. Contact the Muscat instrumentation division to begin.