1Elastic seat sealed gate valveDN250Introduction:

The gate valve has two sealing surfaces, and the most commonly used mode gate valve has two sealing surfaces that form a wedge shape. The wedge angle varies with the valve parameters, usually 50 degrees, and 52 degrees when the medium temperature is not high. The gate of a wedge gate valve can be made as a whole, called a rigid gate; It can also be made into a gate that can produce slight deformation to improve its processability and compensate for the deviation of the sealing surface angle during the processing. This type of gate is called an elastic gate.

Elastic seat seal gate valve, also known as lifting rod gate valve(also known as rising stem gate valve). Usually, there are trapezoidal threads on the lifting rod,Soft sealed gate valveBy using the nut at the top of the valve and the guide groove on the valve body, the rotational motion is converted into linear motion, that is, the operating torque is converted into operating thrust. When opening the valve, when the lifting height of the gate is equal to the diameter of the valve1: At 1x, the fluid channel is completely unobstructed, but during operation, this position cannot be monitored. In actual use, the vertex of the valve stem is used as a marker, that is, the position where it cannot be opened, as its fully open position. To consider the phenomenon of locking due to temperature changes, it is usually done by opening the valve to the top position and then reversing it by 1/2-1 turn as the position for fully opening the valve. Therefore, the fully open position of the valve is determined by the position of the gate (i.e. stroke).


IIElastic seat sealed gate valveDN250Standard quality:

2.1 The valve body material should mainly be ductile iron, cast steel, stainless steel, 316L, and indicate the brand and actual physical and chemical testing data of the cast iron.

2.2 Valve stem material, strive for stainless steel valve stem (2CR13), and large-diameter valves should also have stainless steel embedded valve stems.

2.3 Nut material, made of cast aluminum brass or cast aluminum bronze, with hardness and strength greater than the valve stem.

2.4 The material of the valve stem liner should have a hardness and strength not greater than that of the valve stem, and should not form electrochemical corrosion with the valve stem and valve body when immersed in water.

2.5 Material of sealing surface

① The types of elastic seat sealing gate valves vary, and the sealing methods and material requirements are also different;

② The material, fixing method, and grinding method of the copper ring for ordinary wedge gate valves should be specified;

③ Physical, chemical, and hygiene testing data for elastic seat sealed gate valves and valve plate lining rubber materials;

2.6 Valve shaft packing

① Due to the infrequent opening and closing of elastic seat sealed gate valves in the pipeline network, it is required that the packing should not move or age for several years, and the sealing effect should be maintained for a long time;

② The valve shaft packing should also have good sealing performance when subjected to frequent opening and closing;

③ In view of the above requirements, the valve shaft packing should be kept unchanged for life or more than ten years;

④ If the packing needs to be replaced, the design of the pneumatic valve should consider measures to replace it under water pressure conditions.

IIIElastic seat sealed gate valveDN250Usage and characteristics:

Elastic seat sealed gate valvepurpose

Elastic seat sealed gate valves are widely used as regulating and shut-off devices in fluid pipelines such as tap water, sewage, construction, petroleum, chemical, food, medicine, textile, power, ships, metallurgy, energy systems, etc

Elastic seat sealed gate valveDN250characteristic

1. Flat bottomed valve seat, no accumulation of dirt, making the seal more reliable

2. The valve disc is entirely wrapped in nitrile rubber, and the valve internals are made of corrosion-resistant and rust resistant steel and copper alloy materials, which can be used in sewage systems to adapt to harsh working environments

3. Small size, light weight, easy to install and maintain

4. The valve stem adopts three O-ring seals, greatly reducing the frictional resistance during switching, and the switch is lightweight and leak proof.