Masoneilan 51/52/53 Manual Override: CM and DM Handwheels, HH Hydraulic Handjack

Overview

The Masoneilan 51/52/53 manual override options give an operator a way to move the valve when instrument air is lost. Baker Hughes offers two families on its 51/52/53 cylinder actuators: mechanical handwheels designated CM and DM, and a hydraulic handjack designated HH. The technical specification lists them under “Manual Override Options” and states that a manual override is available for all actuator sizes; the instruction manual describes them in the sections “Handwheel Manual Override (Optional)” and “Hydraulic Manual Override (Optional)”.

In Oman and the GCC, Seven Star LLC supplies the Masoneilan 51/52/53 manual override options in Oman and the GCC. Override hardware is specified when the actuator is built, so this page helps engineers confirm which type their actuator carries, how it is operated safely and which spares the manual lists.

Masoneilan 51/52/53 Manual Override: Which Option Fits Which Actuator

Size 20 spring-return actuators have no mechanical handwheel in the list; their override is hydraulic, and an adjustable travel stop is available on size 20 Model 52/53 only without the handjack. Sizes 16L to 32L, 40 and 46 are not in the override table.

How the Masoneilan 51/52/53 Manual Override Handwheels Work

The CM and DM handwheels are operated the same way. Normal pneumatic operation requires the handwheel in the AUTO position, otherwise travel is locked. To go to manual, remove pneumatic pressure, align the helical groove on the piston rod (item 2) with the adapter groove (item 54) using the handwheel (item 63), then turn the gearbox cover (item 38) clockwise while holding the AUTO button until the MANU button releases. The manual warns that sudden valve movement can occur if the MANU button is not fully released and the cover firmly locked.

To return a Masoneilan 51/52/53 manual override handwheel to automatic, remove pneumatic pressure, set the positioner input signal to the present valve position, bring the actuator to its de-energized position with the handwheel, then turn the cover counter-clockwise while holding MANU until the AUTO button releases. A handwheel left in MANU keeps the stem locked out of automatic control, so the AUTO check belongs on every start-up checklist.

The HH Handjack in the Masoneilan 51/52/53 Manual Override

Baker Hughes describes the hydraulic handjack as a secondary control system that operates the valve when the primary pneumatic system fails, working as a single-acting cylinder against spring load or in double-acting mode. It needs no adjustment and only minimal servicing, namely filling the reservoir. The assembly ships filled, with a pipe plug in the breather port that must be replaced by the breather plug before operation, with the breather at the top of the reservoir.

With the bypass valve closed, working the handjack moves the stem to full travel; opening the bypass returns it to its normal or fail-safe position, and the bypass must stay open during pneumatic operation. To refill, fill the reservoir about one-half full with Mobil DTE 24 hydraulic fluid or equivalent, stroke the actuator to full travel while topping up, then fit the breather plug. Do not overfill.

Weight Added by a Masoneilan 51/52/53 Manual Override

An override changes the weight of the actuator. According to the 51/52/53 technical specification a Model 51 size 12 weighs 179 lb (81 kg) and 227 lb (103 kg) with a handwheel; size 16 weighs 386 lb (175 kg) and 529 lb (240 kg); size 24 at 6 in. stroke weighs 714 lb and 970 lb; size 32 weighs 2,116 lb and 2,299 lb. A size 12 Model 52 goes from 412 lb to 456 lb. Height grows too: a size 12 Model 51 at 2.5 in. travel rises from 21.5 in. (546 mm) to 32.2 in. (819 mm) with a handwheel, so check headroom before a retrofit.

Parts in the Masoneilan 51/52/53 Manual Override

Table 5 of the instruction manual gives the override assembly its own parts: gearbox (37), gearbox cover subassembly (38), O-ring (39), thrust bearing (40), adjustment screw (41), locking nut (42), adjustment nut (43), bearing (45), worm gear (52), adapter (54), worm (56), bearing (57), retaining rings (58 and 62), handwheel shaft (59), handwheel (63), grip (64) and directional plate (65). Baker Hughes marks the O-ring (39), thrust bearing (40) and bearings (45 and 57) as recommended spares. Seven Star LLC quotes them against the actuator model and serial number.

Key Features

• Masoneilan 51/52/53 manual override with CM, DM or HH hardware by actuator size
• Mechanical AUTO/MANU handwheel with positive lock-out
• Hydraulic handjack with bypass for size 20 spring-return units
• Mobil DTE 24 reservoir fluid and minimal servicing for the HH option
• Recommended spares identified in the manual

Industrial Applications

Cylinder actuators with manual override operate large control and isolation valves in refineries, gas plants, power stations and water facilities, where the Masoneilan 51/52/53 manual override lets operators position a valve during an air failure or commissioning. The complete actuator is on the Masoneilan Type 51/52/53 piston actuator page, and the soft goods that wear inside the cylinder are on the 50 Series kit page below. Where the valve is a smaller spring-diaphragm unit, compare the Type 87/88 family and the size 16 87/88 kit.

See also the Masoneilan 50 Series soft goods kits, Masoneilan Model 52/53 spring-return actuators and Masoneilan Model 51 double-acting actuator.

Technical Specifications

The table lists the data Baker Hughes publishes for the Masoneilan 51/52/53 manual override options.

Request a Quote for Masoneilan 51/52/53 manual override

Send Seven Star LLC an RFQ for Masoneilan 51/52/53 manual override hardware or spare parts with the actuator model, size and serial number, and tell us whether the unit has a CM or DM handwheel or an HH handjack. In Oman and the GCC, we match the parts to the Baker Hughes documents linked on this page, confirm stock and arrange delivery from Muscat.