Check valve is to rely on the media itself flow and automatically open, closed disc, used to prevent the backflow of the valve, also known as the non-return valve, one-way valve, countercurrent valves, and back pressure valve.
Check valve is an automatic valve, its main role is to prevent the flow of the media, prevent the pump and drive motor reversal, as well as the release of the container medium.
Butterfly valve is also called flap valve, is a simple structure of the regulating valve, can be used for low-voltage pipe medium switch control of the butterfly valve refers to the closure (disc or butterfly plate) for the disc, around the valve shaft rotation to reach the opening and closing of a valve.
Valves can be used to control the flow of various types of fluids, such as air, water, steam, various corrosive mediums, mud, oil, liquid metals and radioactive media. The main function of cutting and throttling is in the pipeline. Butterfly valve headstock is a disc-shaped butterfly plate, in the body around its own axis of rotation, so as to achieve the purpose of opening or closing or adjustment.
The opening and closing parts are opened or closed by the force of the medium flow to prevent the backflow of the media from the valve called check valve.
Check valve belongs to Automatic valve type, mainly used for medium unidirectional flow pipe, only allow medium to flow in one direction to prevent accident.
Check valve According to the structure division, can be divided into lifting type check valve, swing check valve and butterfly check valve three kinds:
1. Lifting type check valve is divided into vertical and horizontal two kinds.
2. Swing Check valves are divided into single, double and multiple three types.
3. Butterfly Check valve is straight-through.
The above kinds of check valve in the connection form can be divided into thread connection, flange connection, welding connection and four kinds of clamp connection.
1, plug valve for regular operation, open and close quickly, lightweight.
2, plug valve fluid resistance is small.
3, plug valve structure is simple, relatively small size, light weight, easy to repair.
4, Good sealing performance
5, not subject to the installation direction of restrictions, the flow of media can be arbitrary. 6, no vibration, small noise.
When installing the plug valve, in order to prevent damage to the plug valve, and ensure the full play of the performance of the plug valve, you should pay attention to the following four points:
1. Make sure the valve is in the open state. Heat the pipe first. As much heat is transferred from the pipe to the plug valve. Avoid prolonging the heating time of the plug valve itself.
2. Use gauze or wire brush to clear the pipe and cutting parts, so that the metal surface shine. It is recommended that you do not use steel wool.
3. First cut the pipe along the vertical direction, and fix, remove the burr, measure the pipe diameter.
4. Solder on the outside of the pipe and inside the weld cover, the flux must be completely covered by the weld surface. Please use the flux sparingly.
Gate valve of the headstock is the gate, the movement direction of the gate and the direction of the fluid perpendicular to the gate valve can only be fully open and full clearance, can not be adjusted and throttling. Gate has two sealing surface, the most commonly used mode gate valve two sealing surface form wedge, wedge-shaped angle with valve parameters, usually 5 °, medium temperature is not high when 2°52 '. Wedge Gate valve can be made into a whole, called a rigid gate, can also be made to produce a small amount of deformation of the gate, in order to improve the process, to make up for the angle of the sealing surface in the processing of the deviation, the gate is called Elastic Gate.
When the gate valve is closed, the sealing surface can be sealed only by the medium pressure, that is, the sealing surface of the gate is pressed to the other side of the valve seat to ensure the seal of the seal surface by the medium pressure, which is the self sealing. Most of the gate valve is a forced seal, that is, the valve closed, to rely on external forces to force the gate pressure to the seat to ensure the sealing surface of the seal. Gate valve of the gate with the stem for straight line movement, called the lift bar gate Valve, also known as the Ming stem gate valve. Usually on the lifter has trapezoidal thread, through the top of the valve nut and valve body on the guide groove, the rotation of the movement into a straight line movement, that is, the operation torque into operation Thrust. When opening the valve, when the gate lifting height equals valve diameter 1:1 time times, the fluid channel is completely unimpeded, but at run time, this position is unable to monitor. In actual use, it is the vertex of the stem as a sign, that is, the position of the open, as its full opening position. In order to consider the temperature changes in the deadlock phenomenon, usually open to the vertex position, and then back to the 1/2-1 ring, as the position of full opening valve. Therefore, the full open position of the valve, according to the position of the gate is the journey to determine. Some gate valve, the stem nut is located on the gate, the handwheel rotates to drive the stem to rotate, but causes the gate board to ascend, this kind of valve is called the Rotary Pole Gate valve, or is called the Dark pole gate valve.
When the gate valve is closed, the sealing surface can be sealed only by the medium pressure, that is, the sealing surface of the gate is pressed to the other side of the valve seat to ensure the seal of the sealing surface, which is the seal.
Most of the gate valve is a forced seal, that is, the valve closed, to rely on external forces to force the gate pressure to the seat to ensure the sealing surface of the seal. Movement mode: Gate valve of the gate with the valve stem for linear movement, also known as the Ming-stem gate valve. Usually on the lifter has trapezoidal thread, through the top of the valve nut and valve body on the guide groove, the rotation of the movement into a straight line movement, that is, the operation torque into operation Thrust. When opening the valve, when the gate lifting height equals valve diameter 1:1 time times, the fluid channel is completely unimpeded, but at run time, this position is unable to monitor. In actual use, it is the vertex of the stem as a sign, that is, the position of the open, as its full opening position. In order to consider the temperature changes in the deadlock phenomenon, usually open to the vertex position, and then back to the 1/2-1 ring, as the position of full opening valve. Therefore, the full open position of the valve, according to the position of the gate (that is, itinerary) to determine. Some gate valve stem nut is located on the gate, the handwheel rotates to drive the stem to rotate, and causes the gate to ascend, this kind of valve is called the Rotary Pole Gate valve or is called the Dark pole gate valve.
1, butterfly valve has a simple structure, small size, light weight, material consumption, small installation size, switch quickly, 90° reciprocating rotation, small driving torque, etc., used to cut, connect, adjust the media in the pipeline, with good fluid control characteristics and close sealing performance.
2, butterfly valve can transport mud, at the mouth of the pipeline to accumulate liquid minimum. Under low pressure, good sealing can be achieved. Good adjustment performance.
3, butterfly plate streamlined design, so that the loss of fluid resistance is a small energy-saving products.
4, valve stem for the rod structure, after the quality treatment, has a good comprehensive mechanical properties and corrosion resistance, abrasion resistance. Butterfly valve at the opening and closing valve stem only for rotation movement and not for take-off and landing operation, stem filler is not easy to destroy, sealed reliable.
and the butterfly plate cone pin fixed, the outside extension end is the anti-punching type design, lest when the stem and the butterfly plate connection accident Break when the stem collapses.
5, the connection way has the flange connection, to the clamp connection, to the welding connection and the lug to clamp connection. Drive form has manual, worm gear Transmission, electric, pneumatic, hydraulic, electro-hydraulic linkage and other executing agencies, can achieve long-distance control and automation operation.
The butterfly plate is driven by the stem, and if you turn over 90°, you can finish the opening and closing.
The deflection angle of the butterfly plate can be changed to control the flow of the media. Working conditions and media: Butterfly valve is applicable to the furnace, gas, natural gas, liquefied petroleum gas, city gas, hot and cold air, chemical smelting and power generation environmental protection, building water and sewerage engineering systems to transport a variety of corrosive, non-corrosive fluid media pipelines, for the regulation and truncation of the flow of media.
Domestic production of gate valve manufacturers more, the connection size is mostly not uniform. Mainly divided into the following major categories: to jb/t2203-1999 "gate valve structure Length" as the main general category.
At present, most of the domestic safety valve manufacturers are in accordance with this standard design and production.
Manual Gate Valve Working principle: Turn the hand round, through the handwheel and stem of the thread of the feed, retreat, lift or drop with the valve stem connected to the valve plate, to open and close the role.
According to the shell/Body material classification, Gate valve can be divided into:
Metallic materials valves: such as carbon steel valves, alloy steel valves, stainless steel valves, cast iron valves, titanium valves, Monel valves, copper alloy valves, lead alloy valves.
Metal Valve Body Liner valve: such as lined with plastic valves, fluorine-lined valves, lined with lead valves, lined with plastic valves, lined with enamel valves. Non-metallic materials valves: such as ceramic valves, glass valves, plastic valves.
Butterfly valve (English: Butterfly valve) refers to the closed piece (disc or butterfly plate) for the disc, rotating around the valve axis to achieve the opening and closing of a valve, in the pipeline mainly cut off and throttle role. Butterfly valve headstock is a disc-shaped butterfly plate, in the body around its own axis of rotation, so as to achieve the purpose of opening or closing or adjustment.
Butterfly valve fully open to the total is less than 90 °, butterfly valve and the butterfly itself has no self-locking ability, for the positioning of the butterfly plate, to the valve stem on the installation of worm gear reducer. The use of worm gear reducer, not only can make the butterfly plate with self-locking ability, so that the butterfly plate stop in any position, but also to improve the operating performance of the valve. Industry-specific Butterfly valve features: High temperature, the applicable pressure range is also higher, the valve nominal size, valve body using carbon steel manufacturing, valve plate sealing ring using metal ring instead of rubber ring. Large high temperature butterfly valve is welded by steel plate, which is mainly used in flue gas duct and pipe of high temperature medium.