Written By: Kashif Zaman Usafzaie
Valves are used for:
1. Full flow of full throttle:
Which is the wide range of valves use, because valves are designed in a way that reduce pressure losses for fluids passing through these valves, diaphragm valve is used with dangerous and toxic liquids.
2. Flow regulating:
Sometimes, we need to regulate flow by changing the valve position between fully open and fully closed and throttling the valve reducing the flow, this is accomplished by using control valves.
3. One-way flow:
Sometimes, we need to prevent liquids in the reverse way, this type of valves is installed at pump or compressor discharge lines to prevent liquid and gas back flow when shut down these equipment. Check valve is a good example for this kind of valves.
watch this video from AONG YouTube Channel:
Types of Valves:
- Gate Valve.
- Plug Valve.
- Diaphragm Valve.
- Ball Valve.
- Globe Valve.
- Butterfly Valve.
read also Valve Types.
here is an explanation about each one of them:
This type is designed to be fully open or fully closed, making a regular opening without any pressure losses and smooth flow.
This type can throttled, because it cause a corrosion in its internal parts, and cannot be closed fully.
This type is a quick action valve when open or closed by rotating its lever, in addition to providing smooth flow and a very little pressure and a very little pressure loss. This type is used in small sizes, and it has few failures.
In this kind of valves there is no contact between the medium and the moving parts that keeps it from oxidizing materials, so this valve can be made of cheap metals. There is diaphragm between the valve and its cover.
This types of valves consist of a round cavity, it provides a full closed position and usually used in petrochemicals industries.
This type is used in small sizes.
This types of valve is used to control liquid flow, and when need to full closed position, is cause a big pressure loss. There is no contact between the seat and the disc which is conic to reduce the corrosion probability.
This type of valves contain a circular disc of diameter same to the valve body.
It is hardly used for full-open position because of the dirt between the body and the disc, in this case it needs to be opened and cleaned too much.
Leak from packing happens too much in this valve too much.
All valves are used to control the flow, but this type is used to prevent reverse flow, it is used
at compressor or pump discharge lines.
The common problems in this valve is the damage between the disc and the body because of the continuous crash, and the accumulation of dirt’s which leads to reverse flow.
read also What Does Choke Valve Mean?