Any device that regulates the flow of gases or liquids or slurries by opening, closing or partially obstructing passageways is known as a valve. Extremely common as pipe-plumbing fitting, these devices are found in almost all households and are available in a variety of sizes and fittings corresponding to the requirement of the user. The most common ones are ball valve and butterfly valve. Valves are also classified according to how they are actuated, and the categories span over hydraulic, pneumatic, manual, solenoid and motor. The valves found at home are mostly manual, but for large valves used in commercial applications as well as the extremely large ones used at power plants for electricity generation, operating a valve manually is impossible and pneumatically or hydraulically is too expensive, in such scenarios we use motor operated valves.
Big pipe lines require big valves which need strong torque for On/OFF condition, the popular pneumatic controls went out of fashion with increasing size of the valves. Even though we can use a Pneumatic Valve with a double acting piston actuator, the total cost of deployment goes up since the accessories involved cost far more. The involvement of pneumatic amplifier and large actuators increases cost factors too. However by using a Motor Operated Valve we reduce effective costs, since deployment consists of a motor that rotates a gear-set which in turn rotates the valve. This system when deployed correctly is energy efficient and has lower setup costs than other available options.
The only major concern with these systems is Valve Stem Seal Leakage in which case the motor can be put into a compromising condition and it might malfunction. By placing the rotor in inside a case that contains the fluid pressure and keeping the electric motor stator isolated outside in a case the problem can be solved. These valves can also be slow-operating solenoid valve enabled which prevent water hammer or liquid velocity shock.
These motor operated valves do not just have deployment in the large valve market such as those of power plants but they also find deployment in scenarios where automatic valve control is required. For example in refrigerators which require a control over the amount of refrigerant to flow through the cooling system, or advanced engines in which the flow of lubricants and other fluids is required to be accurately and precisely controlled. Being electrically controlled, these valves are extremely precise and can be calibrated for usage in any scenario.
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