Gate valve gate the performance comparison of several different structure

Gate valve gate is in the pipeline are wide a gate valve, main connect and block medium. Does not apply to regulate the flow of medium, but can according to the size of discretion to determine flow rate of the valve rod ( Such as fire scale seal gate valves with opening and closing of the elastic base seat) 。 Gate valve door compared to other valves door, for pressure, temperature, diameter and other requirements to wide application scope. Gate door according to the internal structure of the different can be divided into: single wedge type gate type, flexible disc type, double disc type, parallel slide type. Depending on the valve stem stents can be divided into: rising stem gate valve gate and non-rising stem gate valve gate. Gate valve door of the main performance advantages are: 1, the valve door fluid resistance is small, due to gate valve gate valve body is straight type, medium flow does not change direction, therefore more other smaller valve gate flow resistance. 2, sealed performance is better cut-off valve, opening and closing is a globe valve. 3, wide applicable scope, except for steam and oil such as media, also applies to contain granular solid medium and high viscosity, also are suitable for making the vent valve and the valve door of low vacuum system to use. 4 and gate valve door is a gate valve with double flow, the flow direction of medium is not subject to restrictions, so is suitable for the medium may change the flow direction of pipeline, and ease of installation. Gate valve door main performance shortcomings are: 1, high design size, the closed a long time. Open when need to ascend to the upper cavity of valve, the valve is closed and the valve plate all fall within the valve seat, so the plate opening and closing valve stroke, long time. 2, because of the gate valve gate valve plate and valve sealing surface friction in the process of opening and closing, so the sealing surface is easy to scratch, has an effect on the sealing performance and service life, and not easy to repair. Several different gate door structure performance comparison: ( 1) Single wedge gate valve gate, simple structure more flexible disc valve b, under the high temperature, sealed performance is not as good as elastic or double gate valve gate valve. C, suitable for medium of high temperature anti-coking. ( 2) Flexible disc gate valves door, it is a special form of wedge type single ram valve. Compared with wedge gate valve gate, at high temperature, good seal performance, ram heated not easily stuck; B, suitable for steam and hot oil and oil and gas medium, and is suitable for frequent switch parts. C, do not apply to easy coked medium. ( 3) Double gate valve gate a, sealed performance is good wedge gate valve gate, when Angle and valve seat sealing surface with not very accurate, still has good sealing performance. B, after the disc sealing surface wear, spherical centers at the bottom of the metal pad can be used after the replacement, generally don't have to be surfacing welding and grinding seal face, this is the single disc and flexible disc does not have advantages. C, suitable for steam and hot oil and oil and gas medium, and is suitable for frequent switch parts. D, do not apply to easy coked medium. ( 4) Parallel type gate door a, sealed performance is worse than other forms of gate valve gate. B, is suitable for low temperature and pressure medium. C, ram, and the valve seat sealing surface processing and maintenance easier than other forms of gate valve gate. Rising stem gate valves and non-rising stem gate door: the difference between a gate valve gate is through the valve rod lifting transmission gate opening and closing of the up and down, rising stem gate valve gate drive screw thread on the top of the valve rod bracket, so by the position of the valve stem determine the open-close position of the ram, and the transmission thread also facilitate daily lubrication maintenance, at the same time from the fluid corrosion, the disadvantage is that the requirement to the installation space is larger. Non-rising stem gate valve gate drive internal threads in the valve body, saved the space of the valve rod bracket, so the whole valve height. To clear the open-close position, it can be installed above the valve cover opening and closing scale, applicable to the sewer (under Such as underground non-rising stem gate door) , pipeline and other places in the narrow space, or dust content in place. Gate valve door can also according to different materials, different ways of connection between different pressure and sealing, and divided into different type of gate door.