Flowserve Limitorque Actuators: General Safety Precautions and Practices

Limitorque multi-turn actuator.

The following are general guidelines for safely operating Limitorque actuators. This post is intended to supplement Flowserve / Limitorque's ongoing efforts to provide information on the safe and proper use of electric valve actuators on industrial globe, gate, ball, butterfly and plug valves. It is critically important to always refer to the installation & maintenance manual before applying, installing and servicing Limitorque actuators. If unsure about any of the recommended safety or installation procedures, contact a factory authorized technician before going any further.

More than 1 million Limitorque actuators have been installed around the world, and some have been in operation for more than 50 years. The ruggedness and reliability of Limitorque electric actuators are among the primary reasons that customers continue to select Limitorque products.

Actuators requiring 90° of rotation to operate are necessary for quarter-turn valves such as ball, butterfly, plug and dampers, and rotary control valves. These types of Limitorque electric actuators are available for operations such as open-close, modulating, network and rotary service.

Multi-turn actuators are required to operate various types of rising stem valves such as gate, slide-gates, globe, check and linear control valves. These types of Limitorque electric actuators are available for operations such as open-close, modulating, network and linear service.

General Safety Precautions

Warning: Read the Installation and Maintenance Manual carefully and completely before attempting to install, operate, or troubleshoot the Limitorque actuator.
Warning: Be aware of electrical hazards. Turn off incoming power before working on the actuator and before opening the switch compartment.
Warning: Potential HIGH PRESSURE vessel — be aware of high-pressure hazards associated with the attached valve or other actuated device when installing or performing maintenance on the actuator. Do not remove the actuator mounting bolts from the valve or actuated device unless the valve or device stem is secured or there is no pressure in the line.
Warning: For maintenance and/or disassembly of the actuator while installed on the valve, ensure that the actuator is not under thrust or torque load. If the valve must be left in service, the valve stem must be locked in such a way as to prevent any movement of the valve stem.
Warning: Do not attempt to remove the spring cartridge cap, housing cover, or stem nut locknut from the actuator while the valve or actuated device is under load.
Warning: Do not manually operate the actuator with devices other than the installed handwheel and declutch lever. Using force beyond the ratings of the actuator and/or using additive force devices such as cheater bars, wheel wrenches, pipe wrenches, or other devices on the actuator handwheel or declutch lever may cause serious personal injury and/or damage to the actuator and valve.
Warning: Do not exceed any design limitations or make modifications to this equipment without first consulting Limitorque.
Warning: Actuators equipped with electrical devices (motors, controls) requiring field wiring must be wired and checked for proper operation by a qualified tradesman.
Warning: Use of the product must be suspended any time it fails to operate properly.
Caution: Do not use oversized motor overload heaters. Instead, look for the cause of the overload.
Caution: Do not operate the valve under motor operation without first setting or checking the limit switch setting and motor direction.
Caution: Do not force the declutch lever into the motor operation position. The lever returns to this position automatically when the motor is energized.
Caution: Do not depress the declutch lever during motor operation to stop valve travel.
Caution: Do not use replacement parts that are not genuine Flowserve Limitorque parts, as serious personal injury and/or damage to the actuator and valve may result.
Caution: Do not lift actuator/gearbox or actuator/valve combinations with only the eye bolts in the SMB actuator. These eye bolts are designed for lifting the SMB actuator only.

General Safety Practices

The following check points should be performed to maintain safe operation of the actuator:

Eye bolts in SMB and SB actuators are designed for lifting only the actuator and not associated gearboxes or valves.
Mount the actuator with the motor in a horizontal plane, if possible.
Keep the switch compartment clean and dry.
Keep the valve stem clean and lubricated.
Set up a periodic operating schedule for infrequently used valves.
Verify all actuator wiring is in accordance with the applicable wiring diagram.
Carefully check for correct motor rotation direction. If the valve closes when open button is pushed, the motor leads may have to be reversed.
Verify the stem nut is secured tightly by the locknut and that the top thread of the locknut is crimped or staked in two places.
Use a protective stem cover. Check valve stem travel and clearance before mounting covers on rising stem valves.

Mead O'Brien Authorized
Blue Ribbon Limitorque Parts & Service

For more information, or if you need field support with any Limitorque actuator, parts, or service, contact one of the following Mead O'Brien offices:

www.meadobrien.com

Mead O’Brien, Inc.
10800 Midwest Industrial Blvd
St. Louis, Missouri 63132
(314) 423-5161

Mead O’Brien, Inc.
1429 Atlantic
North Kansas City, MO 64116
(816) 471-3993

Mead O’Brien, Inc.
16 South Main Street
PO Box 1086
Calvert City, Kentucky 42029-1086
(270) 395-7330

Mead O’Brien, Inc.
824 West Elgin
Broken Arrow, Oklahoma 74012
(918) 251-1588