Reversing the Failure Mode of a SAMSON 3271/3277 Actuator from Fail Open to Fail Close

INSTRUCTIONS

WARNING: Actuators with preloaded springs are under tension. They can be identified by three long bolts protruding from the bottom of the actuator. These should be removed last, and installed first upon re-assembly.

1. With the actuator removed from the valve, unscrew the nuts and bolts on the diaphragm case.
2. Lift off the top diaphragm case.
3. Remove the diaphragm plate assembly consisting of the diaphragm plate, diaphragm, and actuator stem from the actuator case.
4. Remove the springs.
5. Clamp the bottom section of the actuator stem into a vise using protective jaws, ensuring the actuator stem is not damaged.
6. Remove the collar nut.
7. Remove the diaphragm plate from the actuator stem, flip upside-down and place them back onto the actuator stem.
8. Re-install the collar nut.
9. If necessary, apply a suitable lubricant to the actuator stem.
10. Install the diaphragm plate assembly together with the actuator stem pointing downward into the bottom diaphragm case.
11. Place the springs onto the diaphragm plate, centering them in the intended recesses. The final actuator spring range will determine the appropriate springs to be installed.
12. Place the top of the actuator case onto the assembly. Ensure that the air connections on the cases are correctly aligned with each other.
13. Fasten the top and bottom diaphragm cases together using the nuts and bolts. Observe tightening torques.

ABOUT THE SAMSON 3271/3277

The Type 3271 pneumatic rolling diaphragm actuator is designed for all industrial applications. This actuator is a linear motion device ideal for valve sizes ranging from the micro-flow valves to large 20"+ globe control valves.

The Type 3277 pneumatic rolling diaphragm actuator with an integrated accessory attachment area is designed for all industrial applications. This actuator is a linear motion device ideal for valve sizes ranging from the micro-flow valves to 4" globe control valves.

The thrust force of the actuator depends on the actuator area, pneumatic supply pressure, spring stiffness, distance traveled, initial compression of the spring, the number of springs internal to the actuator, etc.

The Type 3271 and Type 3277 Pneumatic Actuators contain a rolling diaphragm and internal springs and have the following special features:

• Low overall height
• Powerful thrust at high stroking speed
• Low friction
• Various bench ranges by varying the number of springs or
• their compression
• No special tools required to change the bench range or to
• reverse the direction of action (also version with handwheel)
• Permissible operating temperatures from –60 to +120 °C

For more information on SAMSON Controls, contact Ives Equipment by calling 877-768-1600 or visiting https://ivesequipment.com.

New Flowserve Worcester Controls Industrial Valve and Actuator Catalog

The latest catalog for Flowserve Worcester Control industrial ball valves, pneumatic actuators and electric actuators, courtesy of Ives Equipment. Worcester was founded in 1955. It supplies valves throughout the world for virtually any application. These include standard flanged ball valves, ANSI and DIN specifications in reduced and full bore, three-piece valves for cryogenic, high pressure, steam, diverter or sampling duty, high integrity valves, multi-way designs, modulating controls or customized solutions.

Download a PDF version of the "Worcester Controls Industrial Valve and Actuator Catalog" here or review in the embedded document below.

Worcester Controls Industrial Valve and Actuator Catalog 2018 from Ives Equipment

Definition: Industrial Valve Actuator

Pneumatic actuator on ball valve.
(Worcester)

Actuators are devices which supply the force and motion to open and close valves. They can be manually, pneumatically, hydraulically, or electrically operated. In common industrial usage, the term actuator generally refers to a device which employs a non-human power source and can respond to a controlling signal. Handles and wheels, technically manual actuators, are not usually referred to as actuators. They do not provide the automation component characteristic of powered units.

Electric actuator (Worcester)

The primary function of a valve actuator is to set and hold the valve position in response to a process control signal. Actuator operation is related to the valve on which it is installed, not the process regulated by the valve. Thus a general purpose actuator may be used across a broad range of applications.

In a control loop, the controller has an input signal parameter, registered from the process, and compares it to a desired setpoint parameter. The controller adjusts its output to eliminate the difference between the process setpoint and process measured condition. The output signal then drives some control element, in this case the actuator, so that the error between setpoint and actual conditions is reduced. The output signal from the controller serves as the input signal to the actuator, resulting in a repositioning of the valve trim to increase or decrease the fluid flow through the valve.

Electro-hydraulic actuator
(MIH Trident)

An actuator must provide sufficient force to open and close its companion valve. The size or power of the actuator must match the operating and torque requirements of the companion valve. After an evaluation is done for the specific application, it may be found that other things must be accommodated by the actuator, such as dynamic fluid properties of the process or the seating and unseating properties of the valve. It is important that each specific application be evaluated to develop a carefully matched valve and actuator for the process.

Hydraulic and electric actuators are readily available in multi-turn and quarter-turn configurations. Pneumatic actuators are generally one of two types applied to quarter-turn valves: scotch-yoke and rack and pinion. A third type of pneumatic actuator, the vane actuator, is also available.

For converting input power into torque, electric actuators use motors and gear boxes while pneumatic actuators use air cylinders. Depending on torque and force required by the valve, the motor horsepower, gearing, and size of pneumatic cylinder may change.

There are almost countless valve actuator variants available in the industrial marketplace. Many are tailored for very narrow application ranges, while others are more generally applied. Special designs can offer more complex operating characteristics. Ultimately, when applying actuators to any type of device, consultation with an application specialist is recommended to help establish and attain proper performance, safety and cost goals, as well as evaluation and matching of the proper actuator to the valve operation requirements. Share your fluid process control requirements with a specialist in valve automation, combining your own process knowledge and experience with their product application expertise to develop effective solutions.

Contact Ives Equipment for any valve actuator application. Visit http://www.ivesequipment.com or call (877) 768-1600.

Industrial Control Valve Actuator Operating Principles

Control valve actuators control fluid in a pipe by varying the orifice size through which the fluid flows. Control valves contain two major components, the valve body and the valve actuator. The valve body provides the fluid connections and immovable restrictor comprised a valve stem and plug that is in contact with the fluid that varies the flow.

The valve actuator is the component that physically moves the restrictor to vary the fluid flow. Three actuator types are used in control valves and they include spring and diaphragm, solenoid, and motor. As the name suggests the spring in diaphragm actuator uses a spring and a diaphragm to move the valve stem and plug.

A 15 PSI pneumatic signal enters the housing at the top of the actuator. As pressure is exerted on the diaphragm a downward force is applied against the spring which moves the restrictor. The diaphragm moves until it creates an equal but opposing force against the spring at which time the motion stops as the plug meets the valve seat. With no air pressure the restrictor is pushed upward by the spring to act as a normally open control valve. To vary the position of the restrictor and flow through the valve, a current to pressure transducer can be used to provide a three to 15 PSI signal to the diaphragm.  At 3 PSI the valve is maintained open, and 15 PSI the valve is maintained closed. Pressures between the three to 15 PSI range proportionally change the flow of the valve. For example a pressure of 9 PSI applied to the diaphragm moves the spring and valve stem to 50 percent operating range.

For on /off control of the valve, a solenoid is used to actuate the valve to a fully closed or fully open position. Applying current to the coil generates a magnetic field that moves the plunger downward against the return spring. With zero current applied to the coil the spring pulls the plunger upwards to the fully open position for a normally open state control valve.

Another method for variable valve positioning uses a motor and is referred to as proportional control mode. Using a gear motor attached to the valve stem a servo amplifier provides a DC control signal that moves the valve to the desired position. Feedback is achieved with the wiper arm attached to the valve stem that sends a signal back to the servo amplifier where the position is monitored the servo amplifier drives the motor until the control signal is equal to the feedback signal.

Watch the video below for an illustrated explanation. For more information on control valves, contact Ives Equipment at 877-768-1600 or visit http://www.ivesequipment.com.

Step-by-Step Instructions for Installing a Samson 3277 Actuator

The Samson 3277 is a pneumatic linear actuator suitable for attachment to Samson Series 240, 250, 280 and 290 control valves, as well as the type 3510 Micro-flow valves. Designed with a rolling diaphragm and internal springs, the Samson 3277 is popular because of its low overall height, fast response, low friction, and its ease to maintain. Attaching the actuator, or replacing one, can be done in minutes, without the need of special tools.


This video provide step-by-step instruction on how to install the 3277 actuator.