Kinds of valves

Published: Last Edited:

This essay has been submitted by a student. This is not an example of the work written by our professional essay writers.

Comparison

There are a lot of kinds of valves such as (ball valves, butterfly valves, gate valves, check valves, needle valves and etc). They are being used depending on the usage. They're carefully chosen to the condition and the environment that the valve will operate in. The usage of the valves can be listed as (throttling valves, block or isolation valves and safety & other special purpose valves).

Valves Listing:

Ball Valve:

The isolation element in this valve is a ball with a hole in its centre, and the hole has to have the same diameter as the inner pipe line that's connected to the valve so there won't be restriction to the flow. One of the ball valve's advantages it can be opened and closed quickly and it's mainly used for high pressured gas and liquids. The working way of a ball valve is very simple, a handle connected to a stem that's also connected to the ball (gate) which can be turned 90 degrees, and when the handle's direction aligns with the flow line the gate opens for the flow.

Advantages:

- Low cost is a big advantage in ball valve.

- Fast control of the ball valve's gate (open / close).

- Simplicity in the design of the valve.

- Handling high pressure and temperature easily.

Disadvantages:

- Significant financial losses to companies that use ball valves in its industry when a leak occurs.

Gate valve:

In this valve the isolating element is a gate or a disc made out of hard steel material, and the operation way of the gate valve is different than the ball valve, which in this valve the gate opens and closes in a vertical way, and it takes longer time but it seals really well. The working way of this valve is by turning a hand wheal which is connected to a stem in a vertical way, and the stem raises when the gate opens fully. The gate valve is a very good isolator for hydrocarbons which is mainly fluids not gases and it's used a lot in the oil sector.

Advantages:

- Excellent sealing quality to fluids for long operation time.

- Usage of the gate valve can be on it's both sides.

Disadvantages:

- Slow opening and closing operation in the gate valve.

- No control on the flow so the valve must either be fully opened or fully closed.

Butterfly valve:

This valve mechanism is very similar to the ball valve; the isolating element in the butterfly valve is a flat circle disc that is connected to a stem which is also connected to a handle. The round disc is fitted in a vertical way in the body of the valve, and turns 90 degrees horizontally. The butterfly valve is mostly used for low pressured gases in the oil industry.

Advantages:

- Fast control in opening and closing the valve which makes it easy to operate.

- Occupying small space between the pipelines.

- Low cost in manufacturing which makes it cheap.

- Low cost in maintenance.

Disadvantages:

- Passing through the valve may occur when using high pressured liquids.

- Can't be used for throttling the flow.

- Using hydrocarbons with this valve might gather Impurities on the disc's surface.

Globe valve:

The isolating object in this valve is a disc shaped plug connected vertically to a stem that opens and closes also in a vertical way. And the shape of the body of the globe valve makes it so special comparing it to other kinds of valves, which is when the flow runs into the valve it hits a lower curve of the body and goes through the opened disc and into a higher level of the valve hitting another curve and then into the other side of the valve. This kind of body shape provides a precise and smooth control to the fluid flow.

Advantages:

- A very excellent throttling valve for controlling the speed of the flow.

- Provides a smooth and precise fluid flow.

- Gives a tight closing and sealing after long opening time.

- Less maintenance to the valve as in doesn't need to be re-seated.

Disadvantages:

- Liquids with solid materials (hydrocarbons) might accumulate at the valves seat and will affect on the flow.

- Takes long time to open and close the valve which is bad in case of an emergency.

Plug valve:

This is also very similar to the ball valve in the function and isolating part, which in the plug valve the isolating element is a tapered cylindrical plug with a rectangle shaped hole in its centre. The working way of the plug valve is by turning a handle 90 degrees to the directing of the flow to open it.

Advantages:

- Mechanism of opening and closing the valve is easy and quick which is safe in case of emergencies.

- Can be used for high pressured liquids and gases, and it can handle pressure up to 350 bar.

- Very good isolator and can stand for long time without leaks.