- Introduction to valves
Gate valve is mainly composed of a stuffy body, a door cover, a valve plate, a valve, a door seat and a sealing packing. It is one of the most common door types among off-class doors. The main purpose of the gap valve is It is for this reason that truncated fluids are often called
It is a "cut-off" valve or a "blocking" valve. There are many different structural forms of valves, and the structural types of sealing elements used in them are different. According to the structure of the sealing element, it can be divided into several different types.
- According to the valve stem classification, according to the valve stem type, it can be divided into open stem gate valve and concealed stem gate valve.
1. The Buddha-shaped pattern of the open-opening bay valve is placed outside the net body and is located on the upper part of the valve stem. By rotating the valve mother, the net rod drives the bay plate to rise and lower synchronously to achieve door closing, so it is easy to identify the net. The door is closed to avoid misoperation.
Because the valve stem nut is outside the body, it is conducive to lubrication. At the same time, the opening and closing status is intuitive and obvious, so it is widely used. In the black ring filling, the outer thread of the tobacco stem is susceptible to damage and corrosion, and even the sound mold. Its shortcomings The height of the Yanmen letter opening bureau is usually large.
A stroke is added to the original height of the valve, so a large operating space is required.
2. The concealed stem valve is also called a rotating stem valve (also called a concealed stem mode valve). The valve stem nut is placed inside the valve body and is directly connected to the medium. It is often fixed on the valve plate. The rotation of the stem makes the valve The rod nut drives the intermediate plate to move up and down to complete opening and closing. usually
There is a trapezoidal pattern at the bottom of the net. Through the thread at the bottom of the gate and the guide on the valve row, the rotary remote motion is changed into a linear remote motion, that is, the operation is changed into a slow thrust. Since the transmission lines are located inside the body, they are susceptible to corrosion and
Lubrication cannot be performed, the opening degree cannot be directly observed, and there is no additional indicating device. However, its valve stem does not move up and down, and the required operating space is small, so it is suitable for situations with limited position and dense pipelines.
- According to the structure classification, it can be divided into two types: wedge gate valve and parallel gate valve. That is, the wedge gate valve is called a wedge gate valve, and the parallel gate valve is a flat gate valve.
1 Flat plate valve means that the sealing surface is parallel to the vertical center line, so the sealing surfaces of the valve body and the intermediate plate are also parallel to each other. The most common type of this type of valve is the double-plate type, in order to seal the body and the intermediate plate when closed. The face-to-face joints are closely connected and are often used on two sniffing boards.
Clamped with double-sided thrust wedge. Mostly used in low-pressure pipelines such as small pipelines. There are also parallel smell valves that use a single smell plate, but it is rare.
2. The wedge-type valve means that the sealing surface is at a certain angle with the vertical center line, that is, the valves on both covers are single or double. The advantage of the double gate type is that the sealing and angle requirements are lower, temperature changes are not easy to cause the gate to wedge, and gaskets can be added to compensate for sealing surface wear. The disadvantage is that the structure is complex and easy to stick in dry media. More importantly, the gate plate is easy to fall off after the upper and lower baffles are rusted for many years.
