Gate valve by function and main purpose

(1) Shut-off valve

This kind of gate valve has the function of opening and closing. It is installed on the inlet and outlet of cold and heat sources, the inlet and outlet of machinery and equipment, on the branch line of the pipeline (including the riser), and can also be used as a water inlet valve and an exhaust valve. Common shut-off valves include gate valves, globe valves, gate valves and butterfly valves.

Gate valve can be divided into dark rod and dark rod, single gate and double gate, wedge gate and parallel face gate, etc. The sealing performance of the gate valve is not very good when it is closed, and it is difficult to open the large-diameter gate valve; the size of the oil circuit board along the flow direction is small, the flow friction resistance is small, and the outer diameter of the gate valve has a large span.

According to the material inflow, the cut-off valve is divided into three types: direct connection type, oblique type and direct current type, and there are dark rods and dark rods. The closing seal of the globe valve is better than that of the gate valve, the oil circuit board is long, the flow friction resistance is large, and the larger outer diameter is DN200.

The valve core of the gate valve is a perforated sphere. The plate-moving valve seat is fully open when the ball is punched facing the centerline of the pipeline, and is fully closed when turned 90°. The gate valve has certain adjustment characteristics and is closed more tightly.

The valve core of the butterfly valve is an annular perforated plate, which can rotate along the slewing bearing on the centerline of the vertical pipeline. When the plan view of the perforated plate is consistent with the center line of the pipeline, it is fully open; when the plan view of the gate is vertical to the center line of the pipeline, it is fully closed. Butterfly valve oil circuit board length is small, flow friction resistance is small, and the price is higher than gate valve and globe valve.

(2) Check valve

This kind of gate valve is used to avoid the reverse flow of the material. It uses the mechanical energy of the liquid itself to open automatically, and automatically closes when it flows in the opposite direction. It is located at the outlet of the centrifugal pump, the outlet of the trap and other areas that do not allow the liquid to flow in the opposite direction. Check valves are divided into three types: swing type, lift system and wafer type. For the swing check valve, the liquid only flows from left to right, and it is automatically turned off when it flows in the opposite direction. For the check valve of the lifting system, when the liquid flows from left to right, the valve core extends to create a channel, and when the liquid flows in the opposite direction, the valve core is clamped to the high-pressure gate valve and closed. For the wafer check valve, when the liquid flows from left to right, the spool is opened to create a channel. When the liquid flows in the opposite direction, the spool is clamped to the high-pressure gate valve and closed. The wafer check valve can be Multiple installations, small size, light weight and compact structure.

(3) regulating valve

The pressure difference between the front and rear of the gate valve is constant. Generally, when the opening degree of the gate valve changes within a large range, the total flow change is not large, and when it reaches a certain opening degree, the total flow changes greatly, that is, the adjustment characteristics are not good. The regulating valve can change the spool stroke arrangement according to the position and size of the data signal to change the friction resistance of the gate valve, and then adjust the gate valve for the purpose of total flow. The regulating valve is divided into manual regulating valve and automatic regulating valve, and there are many types of manual or automatic regulating valve, and their regulating characteristics are also different. Automatic regulating valve includes self-operated flow control valve and self-operated pressure difference regulating valve.

(4) Vacuum pumps

Vacuum pumps include vacuum ball valves, vacuum pump diaphragm valves, vacuum pump filling valves, pneumatic vacuum valves, etc. Its function is that in the ultrafiltration device, it is used to change the cyclone orientation, adjust the total gas flow size, and the ultrafiltration device components that are disconnected or connected to the pipeline are called vacuum valves.

(5) Unique main purpose category

Unique main purpose categories include pigging valves, venting valves, filter valves, automatic exhaust valves, filter devices, etc.

The automatic exhaust valve is an indispensable auxiliary component in the pipeline system software, and is widely used in heating furnaces, central air conditioners, petrochemicals, and sewage pipes. It is usually installed in the main position or elbow, etc., to remove unnecessary gas in the pipeline, improve the efficiency of pipeline surface application and reduce energy consumption.