Friday, May 23, 2014

Gate Valves – Stop the flow

A valve is a mechanical device which is used in various industries to regulate or stop the flow of a fluid . It basically connects with the pressure holding vessels that establishes the flow of fluid. There are three types of valves which are used to connect with such vessels viz. Gate Valves, Check Valves and Globe Valves.A specific type of Lined Valves is used for performing particular function like gate valves can completely stop the flow, globe valve regulates the flow or can provide throttle flow and gate valve is used to stop the back flow.

A Brief Detail About Gate valves

As above said, a Gate valves is used to stop the flow of liquid completely. This type of valve is designed in such a way that it can handle thick or viscous fluid like oils, grease, cream etc. Gate valve (which is classified under lined valve) works on the principle of on-off service therefore works on the principle of on-off service therefore it is widely used in those systems where complete shut-off is required and in which, use of valve is limited.

How Gate Valve Works?

A gate valve is constructed by using three components – Body, Bonnet and Trim where Trim includes two functioning parts known as Stem and Seat.

When a stem is switched to open the valve, the closure element called “Disk” shifts from the path of the stream or flow of liquid and fluid will flow smoothly without facing any resistance. But in case of fully closed, a round disk will seal the contact surface which provides complete obstruction in the path of stream and stops it from flowing.

This gate valve must be used either in fully open or fully closed condition to prevent it from damage. However, it can be used in partially opened state to provide obstruction to the flow of fluid, but it must be infrequent because in partial opened position the liquid will flow in non-linear manner and cause vibration to the seat and disk that further becomes the reason for leakage and damage.

Classification of Gate Valve

Following is the classification chart : 
Lined Valves

Gate Valve is classified in two ways – Parallel and Wedge-Shaped.

A Parallel Slide Valve does not require any mechanical effort for getting closed rather it accounts tightness by using line pressure. This eliminates the chance of binding which usually occurs due to temperature fluctuation in the valve. In Parallel Gate Valve, flat disc gate is placed between two parallel seats to seal them.

Knife Valve: The design of this valve contains the sharp edge at the bottom to cut the solids or slurries.

Through-Conduit: This valve consists of rectangular shaped element that closes the valve. When this closure element is raised up then the valve is considered as completely shut-off otherwise open.

A Wedge Gate Valve have wedge shaped closure element which is used to seal both high and low fluid pressure. It provides high seat tightness and hence, tight shut-off.

Solid Wedge: This type of valve has high strength and can be placed in any position. It is widely used where turbulent flow is needed.

Flexible Wedge: Flexible wedge shaped disk is used to correct the mismatch between the seats. The strength of this valve is inversely proportional to the cut around the perimeter of disc.

Split Wedge: Split widget is popular for its self-adjusting and self-aligning properties. This wedge sort comprises of two-piece disc which situates between the tapered seats in the valve body.

What are the Features of Gate Valves?
  • Available in large sizes
  • Can handle slurries and thick fluid
  • Easy to assemble or remove
  • Not so expensive
  • Two-way valve
  • Less resistance
  • Huge capacity
  • Efficient seals
Which Material is Used for Constructing Gate Valve?

Raw Material plays an important role in the valve construction so that it can work properly and in a hassle free way. Since gate valves are used in varied range of applications and these come in contact with different kinds of liquid therefore, to prevent these from the failure, suitable raw materials should be used for its designing and fabrication. The choice of material mostly depends on the atmospheric condition and media. Some common raw materials that are presently being used for making gate valves are brass, bronze, gray iron, gamut of steel types, and various alloys. Besides all these, in order to choose suitable valve material there are some key points which must be considered. These are:
  • Temperature under which which it would be operated
  • How much pressure it has to handle
  • Availability of material and maintenance
  • Compatibility of material with type of fluid
  • Exposure to media
How to find Valves Manufacturers and Suppliers Online?

It is very easy to find trusted suppliers of different kinds of valve including gate valves online, as there are many B2B portals which provide the information of the regarding manufacturers. Each offers a wide range of quality valves accompanied with a range of appreciable features, such as corrosion resistance, durability, long term functionality and much more.

Buyers can avail quality Gate valves, Plug Valves, Globe Valves, Check valves and other types of valves for industrial use from reliable suppliers which are appropriate for various requirements and can also be availed in customized technical specifications.