Valves:
Types of Valves
1)Butterfly Valves.
2) Gate valve.
3) Globe valve
4) Angle Globe valve.
5) Y- Globe valve.
6) Plug valve.
7) Ball Valve.
8) Swing check Valve.
9) Lift Check valve.
10) Control Valves
*3-way valve
*2-way valve
11) Y-strainer
12) Air vents.
Butterfly Valves
Types of butterfly valves
Uses an electric for controlling the valve with a 4-20mA control signal and are typically used for high precision regulation and time-sensitive application.
It is used for high precision application and uses compressed air for actuation.
Typically used for applications requiring large torques for opening and closing the valve, such as high pressure and high viscosity applications.
Manually operated butterfly valves make use of a handwheel, crank, or lever to operate the valve. Smaller manual valves are typically fitted with a lever. For larger sizes, handwheels are provided and are accompanied by a gearbox to transfer the torque with a high mechanical advantage.
Advantages of Butterfly valves
Gate valve
Gate valves are known as shutoff valves are designed for shutoff duty.
It can't be used for throttling operation.
It provide very low pressure drop.
Globe valve
Globe, angle, and y globe valves are of the same basic designed primarily for throttling operation.
Angle valve basic design same as globe valve but it can replace on elbow fitting.
This valves can be opened quickly & less in wear compared to the gate valves.
Advantages:
• Faster to open or close.
• Throttling to control the flow to any desired degree.
Disadvantages.
• Seat Disc wear in partial operation.
Plug valves:
• This valves are used for balancing duty.
• It is used in smaller applications, limited in size & Expensive.
Advantages of plug valve
The main advantages of a plug valve are:
• It has a simple design and fewer parts
• It can be quickly open or close.
• This valve offers minimal resistance to flow.
• The use of multi-port designs helps in reducing the number of valves needed and permits a change in the flow direction.
• It provides a reliable leak-tight service.
• They are easy to clean which can be done without removing the body from the piping system.
Disadvantages of plug valve
The limitations or drawbacks of a plug valve are:
- As a large amount of friction is required to rotate the plug, which results in greater force to operate these valves.
- Actuators are required for larger valves.
- These plug valves cost more than ball valves which have a similar design.
- Pressure drop is more due to reducing port.
Ball Valves:
This valves are used for fully open ,close operation.
Advantages.
• Low cost
• Low Pressure Drop & Tight shut off.
• Low leakage & Tight Sealing.
• Small in size & low in weight.
• Low Torque to open
Disadvantages.
This valves are not suitable for sustainable throttle system. Fluid trapped in the ball in the closed position may cause problem of build up of vapor pressure and corrosion.
Check valve or Non return valve
Check valves are used to prevent the back flow in piping system.
The types are Swing Check valve, Lift check valve.
Swing Check valve
• It can be used in horizontal & Vertical upward flow direction only.
• Generally used in combination with Gate valves.
Lift check valves
•The lift check operates in a manner similar to that of a globe valve
•The disc is seated by back flow or by gravity when there is no flow.
•It can be only installed in horizontal piping only on combination with globe, angle, y- valves.
Advantages :
1) Prevents backflow
2) Maintains pressure
3) Serves as backup system
4) Most can be used horizontally as well as vertically
Disadvantages :
1) Can't be used with pulsating systems
2) Closing element may slam close causing damage and excessive wear
Control Valves
• 2- way valves
• 3- way valves(Diverting & Mixing)
2- way valves
These valves are used in variable flow systems & Variable flow pump is used
They throttle the flow for part load control instead of by-passing the flow around the coil.
There are two types
1) On/off Operation.(Temp set point if reached It will off).
2) Modulating.(bases on temperature in space).
3- way valves
• These valves are used in many application such as flow rate variation, Temperature variation, and primary, secondary pumping systems in both 2 pipe & 4 pipe systems.
• 3 way mixing valves have 2 inlets and one outlet. 3 way diverting valves have one inlet and two outlets. Mixing valves are used to vary the flow through a load.
• 3 way diverting valves are used to direct the flow one way or another and are useful in applications like 2 pipe change over or in bypass systems.
Strainers
• It is used to prevent dust & debris from entering the equipment.
• It is installed in the inlet of Chiller , suction side of Pump.
• It is importantly used in open loop Loop system & once through systems.
Air vents
Air vents are used to remove unwanted air from a closed loop system. They should be loacated at high points in the system where air may be present.
Two types of air vents are used in piping system
1.Manual Air vent.
2. Automatic Air vent.
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