Stainless steel gate valve The types of gate valves can be divided into wedge gate gate valves and parallel gate gate valves according to the sealing surface configuration. The wedge gate gate valves can be divided into: single gate type, double gate type and elastic gate type; parallel gate type gate valves can be Divided into single gate type and double gate type. According to the thread position of the valve stem, it can be divided into two types: open gate valve and dark gate valve. This type of valve should generally be installed horizontally in the pipeline. When the gate valve is closed, the sealing surface can be sealed only by the medium pressure, that is, the sealing surface of the ram is pressed against the valve seat on the other side by the medium pressure to ensure the sealing of the sealing surface, which is self-sealing. Most of the gate valves are forced to seal, that is, when the valve is closed, the external force is forced to press the gate to the valve seat to ensure the sealing of the sealing surface. The gate of the gate valve moves linearly with the valve stem, which is called the lift gate valve (also called the open gate valve). Usually there is a trapezoidal thread on the lifting rod, and the rotary motion is changed into a linear motion by the nut at the top end of the valve and the guide groove on the valve body, that is, the operating torque is changed to the operating thrust. When the valve is opened, when the lifting height of the gate is equal to 1:1 times the diameter of the valve, the passage of the fluid is completely unblocked, but this position cannot be monitored during operation. In actual use, the apex of the valve stem is used as a mark, that is, the position where the valve is opened, as its fully open position. In order to consider the temperature change, the lock phenomenon is usually turned on to the apex position, and then back to 1/2-1 turn as the position of the fully open valve. Therefore, the fully open position of the valve is determined by the position of the shutter (ie stroke). In some gate valves, the stem nut is arranged on the gate plate, and the rotation of the hand wheel drives the valve stem to rotate, and the shutter is lifted. This valve is called a rotary lever gate valve or a dark rod gate valve. 1. The working principle of the manual gate valve Turning the handwheel, through the advancement and retreat of the thread of the handwheel and the stem, lifting or lowering the valve plate connected with the valve stem to achieve the function of opening and closing The gate valve has the following advantages: The fluid resistance is small, and the sealing surface is less brushed and eroded by the medium. Opening and closing is more labor-saving. The flow direction of the medium is not limited, and it does not disturb the flow and does not reduce the pressure. The shape is simple, the structure length is short, the manufacturing process is good, and the application range is wide. The disadvantages of the gate valve are as follows: Erosion and abrasion are easily caused between the sealing surfaces, and maintenance is difficult. The external dimensions are large, and a certain space is required for opening, and the opening and closing time is long. The structure is more complicated. According to the sealing surface configuration, the type of gate width can be divided into wedge gate valve and parallel gate valve. The wedge gate valve can be divided into: single gate type, double gate type and elastic gate type; parallel gate type gate valve Can be divided into single gate type and double gate type. According to the thread position of the valve stem, it can be divided into two types: open gate valve and dark gate valve. The following matters should be noted for the installation and maintenance of the gate valve: The handwheel, handle and transmission mechanism are not allowed to be used for lifting, and collision is strictly prohibited. The double gate gate valve should be installed vertically (ie the stem is in the vertical position and the handwheel is on the top). The gate valve with the bypass valve should open the bypass valve before opening (to balance the differential pressure between the inlet and outlet and reduce the opening force). The gate valve with transmission mechanism is installed according to the product manual. If the valve is used frequently, it should be lubricated at least once a month. Structural features: The general gate valves used in the market have been leaking or rusting for a long time. The company introduced the high-grade rubber sealing valve produced by European high-tech rubber and valve manufacturing technology, which overcomes the defects of general gate valve sealing, rust and other elastic seats. The sealing valve uses the elastic ram to produce a slight elastic deformation compensation effect to achieve a good sealing effect. The valve has the advantages of light switch, reliable sealing, good elastic memory and long service life. Can be widely used in tap water, sewage, construction, petroleum, chemical, food, pharmaceutical, textile, electric power, shipbuilding, metallurgy, energy systems and other body pipelines as a regulating and intercepting device. 2. Characteristics of the gate valve Light weight: The weight is reduced by about 20%~30% compared with the traditional gate valve, and the installation and maintenance are convenient. Flat-bottomed gate: Traditional gate valves are often deposited in the groove of the valve bottom due to foreign objects such as stones, wood blocks, cement, iron filings, debris, etc. after the water is washed, which is easy to close and form a leak. The bottom of the elastic seat sealing gate valve adopts the same flat bottom design as the water pipe machine, which is not easy to cause debris accumulation, so that the fluid is unobstructed. Integral encapsulation: The ram is made of high-quality rubber for the whole inner and outer rubber. The first-class rubber vulcanization technology in Europe enables the vulcanized ram to ensure precise geometrical dimensions, and the rubber and spheroidal cast slabs are secure and not easy to fall off. Flexible memory is good. water Precision cast body: The valve body is precision cast, and the precise geometry allows the valve body to be sealed without any finishing. 3. Construction and installation points 1) The installation position, height, and import and export direction must meet the design requirements, and the connection should be firm and tight. 2) All kinds of manual valves installed on the insulated pipe, the handles shall not be downward. 3) The visual inspection must be carried out before the valve is installed. The nameplate of the valve should comply with the current national standard "General Valve Mark" GB 12220. For valves with a working pressure greater than 1.0 MPa and a shut-off effect on the main pipe, the strength and tight performance tests shall be carried out before installation, and shall be used after passing the test. In the strength test, the test pressure is 1.5 times the nominal pressure, the duration is not less than 5 min, and the valve casing and the packing should be free of leakage. In the rigorous test, the test pressure is 1.1 times of the nominal pressure; the test pressure shall meet the requirements of GB 50243 during the duration of the test, and the leakage of the valve sealing surface shall be qualified. 4. The gate valve has the following advantages 1. The fluid resistance is small, and the sealing surface is less brushed and eroded by the medium. 2, opening and closing is more labor-saving. 3. The flow direction of the medium is not restricted, and it does not disturb the flow and does not reduce the pressure. 4. Simple shape, short structure length, good manufacturing process and wide application range. 5. The disadvantages of the gate valve are as follows 1. Erosion and abrasion are easily caused between the sealing surfaces, and maintenance is difficult. 2. The external dimensions are large, and a certain space is required for opening, and the opening and closing time is long. 3. The structure is more complicated. According to the sealing surface configuration, the type of gate width can be divided into wedge gate valve and parallel gate valve. The wedge gate valve can be divided into: single gate type, double gate type and elastic gate type; parallel gate type gate valve Can be divided into single gate type and double gate type. According to the thread position of the valve stem, it can be divided into two types: open gate valve and dark gate valve. 6. Stainless steel gate valve technical parameters 1. Nominal pressure: 1.0MPa, 1.6MPa, 2.5MPa 2. Shell test pressure: P=1.5PN 3. Seal test pressure: P = 1.1PN 4. Export pressure: PN1.0MPa stainless steel gate valve 0.09~0.8MPa PN1.6MPa stainless steel gate valve 0.10~1.2MPa PN2.5MPa stainless steel gate valve 0.15~1.6MPa 5. Applicable medium: water 6, applicable temperature: 0 ° C ~ 180 ° C 7. Structural features 1. The selection of materials is in line with relevant domestic and international standards, and the overall quality of materials is high. 2. It meets the requirements of advanced standards at home and abroad, with reliable sealing, excellent performance and beautiful appearance. 3. The sealing pair is advanced and reasonable. The sealing surfaces of the ram and the valve seat are made of Stellite cobalt-based hard alloy with different hardness. The sealing is reliable, high hardness, wear resistance, high temperature resistance and corrosion resistance. Good anti-scratch performance and long life. 4. The valve stem is quenched and tempered and surface nitrided, which has good corrosion resistance, scratch resistance and wear resistance. 5, the use of wedge-type elastic ram structure, medium and large caliber thrust bearing, small friction, and equipped with impact hand wheel, easy to open and close. 6, can use a variety of piping flange standards and flange sealing surface form to meet various engineering needs and user requirements.