HVAC Questions & Answers
Find the top Heating, ventilation, and air conditioning HVAC Questions & Answers for your interview preparation. HVAC Questions & Answers How Does a Refrigerant Compressor Work? The compressor constricts the…
Why Pressure & Temperature Compensation required for Orifice Flow Meters ?
Flow Measurement Pressure & Temperature Compensation. Orifice Flow Meters Temperature and Pressure Compensation requirement, purpose, advantages and formula
What is a Disc Valve ?
Disc valves (often referred to as eccentric disk valves, or as high-performance butterfly valves) are a variation on the butterfly design intended to improve seat shut-off. The disc’s center is…
Different Types of Flow Elements
Different Types of Flow Elements or Flow Sensors are Pitot tube, Annubar flow element, orifice, venturi, flow nozzle and Differential Pressure Flow Sensors.
Electrical Actuators
Electric motors have long been used to actuate large valves, especially valves operated as on/off (“shutoff”) devices. Advances in motor design and motor control circuitry have brought motor operated valve…
Dampers and Louvres
A damper (otherwise known as a louvre) is a multi-element flow control device generally used to throttle large flows of air at low pressure. Dampers find common application in furnace…
Rotary Stem Valves
A different strategy for controlling the flow of fluid is to insert a rotary element into the flow path. Instead of sliding a stem into and out of the valve…
Working Principle of Pneumatic Actuators
Pneumatic actuators use instrument air pressure to apply force on the diaphragm to move the valve actuator and then to position valve stem. The following photograph shows a cut-away control…
Working Principle of Hydraulic Actuators
Hydraulic actuators use liquid pressure rather than instrument air pressure to apply force on the diaphragm to move the valve actuator and then to position valve stem. Nearly all hydraulic…
Working Principle of Self Operated Valves
Although not a type of actuator itself, a form of actuation worthy of mention is where the process fluid pressure itself actuates a valve mechanism. The self-operating valve principle may…
