A null type recorder is a type of strip chart recorder. These recorders are based on the principle of null condition or self balancing principle.
What is Galvanometer Type Recorder? Working & Diagram
Figure 1: Galvanometer Type Recorder.
A galvanometer type recorder is a type of strip chart recorder and it is based on the principle of deflection i.e., the data is recorded due to deflection of pointer. The pointer deflects because of deflecting torque which is proportional to the magnitude of the variable being recorded.
What is Laser Doppler Anemometer? Working Principle, Construction, Diagram & Applications
Working Principle of Laser Doppler Anemometer
Laser Doppler Anemometer or Laser Doppler velocimetry (LDV), works on the principle of Doppler effect. It states that whenever a laser beam passes through the moving fluid, frequency shift takes place in the light scattered by the small particles present in that fluid. This shift in the frequency of the beam is directly proportional to the velocity of the fluid flow.
What is Turbine Flow Meter? Working Principle, Construction, Diagram & Applications
Figure 1: Turbine Flow Meter.
Working Principle of Turbine Flow Meter
The permanent magnet attached to the body of rotor is polarized at 90° to the axis of rotation. When the rotor rotates due to the velocity of the fluid (V) the permanent magnet also rotates along with the rotor. Therefore a rotating magnetic field will be generated. which is then cut by the pick-up coil. Due to this A.C. voltage pulses are generated whose frequency is directly proportional to the flow rate.
Measuring range: Accurate flow measurement overa wide flow range = 0.1 to 50,000 gallons/mm. Sizes = 6.35 mm to 60 mm.
What is Hydraulic Dynamometer? Working, Diagram, Construction & Advantages
Hydraulic dynamometer is an absorption type of dynamometer. This dynamometer uses fluid friction for their operation i.e., to dissipate mechanical energy. Therefore, it is also known as fluid friction dynamometer.
What is Control System? Theory, Diagram, Elements & Examples
A system in which input has a command over the output or a system in which input has a control over the output is called a control system. A water tap can be taken as simple and best example of a control system. Here the flow of water (i.e., the output) is mechanically controlled by the movement of valve (i.e., input). The diagrammatic representation of simple control system is shown below
What is Unloading Valve? Types, Working, Construction & Diagram
Unloading valves are pressure control valves, used to discharge the excess fluid from the pump to the tank with a small or zero pressure drop. These valves are used in high-low pump circuit applications where two pumps are used to move an actuator at high speed and low pressure.
What is Pressure Sequence Valve? Working, Construction & Diagram
Pressure sequence valve is a type of pressure control valve that is used in the applications where the two hydraulic cylinders are operating in a sequence, to allow the fluid flow to those cylinders in a pre-determined sequence.
What is Compound Pressure Relief Valve? Working, Construction & Diagram
Compound pressure relief valve also performs the same function as the simple pressure relief valve but it is pilot operated and is used to accommodate the high pressure and high flow capacities.
What is Servo Valve? Types, Working, Construction, Diagram & Applications
A direction control valve which has ability of infinite positioning and regulates the flow quantity, speed of motor is called servo valve. Mostly hydro electric servo systems employ servo valves for higher efficiency, response time and compactness. These valves are connected to feedback sensors to control the actuator’s position, velocity and acceleration very precisely.
Types of Servo Valve
It is classified into two types.
- Electro hydraulic servo valve.
- Mechanical hydraulic servo valve.
Electro hydraulic servo valve
Electro hydraulic Servo valves can be single stage or multistage, where the movement of valve spool is proportional to the input electric signal. The figure 1 below shows the multistage hydro electric servo valve which mainly consists of torque motor, double nozzle and a spool.