A coal washing plant in 1998 Dense Medium transformation, the coal washing process is mainly jigging, HM cyclone selection, coal flotation, dosing process is mainly solid-liquid two-phase mixed medium suspension , Medium on the pipeline, equipment, serious wear and tear, the pipeline used in the main gate valve knife.
The knife gate valve now used by the coal washing plant is divided into manual, electric and electro-hydraulic three forms, the main models are PZ73 manual wafer knife-type gate valve, PZ973 electric wafer-type knife gate valve, PZ273 electro-hydraulic wafer clamp Gate valve, the manufacturer is mainly in Zhejiang Cheng valve plant. Knife gate valve by the valve, valve plate, stem, handwheel (drive) and seal components, gate, stem and cover made of stainless steel, good wear resistance, the valve body is carbon steel. Seal is divided into rubber, fluorine plastic and alloy steel seal. Knife-type gate valve opening and closing pieces of the gate, the direction of movement of the gate and the fluid perpendicular to the direction of relying on the handle or electro-hydraulic device, driven by the valve stem to achieve gate opening and closing. 1. Knife gate valve features
1) The knife-type gate valve adopts the clamp type structure, which has the advantages of compact structure, small size, light weight, small occupation space, easy installation, opening and closing the gate valve to save labor and reducing the labor intensity of maintenance workers.
2) The bottom of the gate of the knife-type gate valve is in the shape of a blade, which has the function of cutting materials, fibers and sundries and can not easily block the gate and has good opening and closing functions.
3) a reasonable sealing surface and packing seal design, making the valve sealed and reliable.
4) multiple support points ram, the gate has a good self-aligning.
5) knife mounted on the top of the rigid Teflon scraper, to prevent dust, gravel and other abrasives into the stuffing box to improve the life of the gate. 2. Usage and precautions
1) PZ73-type wafer-type knife gate valve in our plant mainly used in heavy media and slime water pipe, the main cut-off to do in the pipeline, can not be used as a regulator of flow, the gate should be fully open or fully closed, so as not to seal And the gate by erosion, accelerated wear and tear, greatly reducing the service life.
2) The installation should pay attention to the valve installation direction, the chamfer side of the valve is closed with the pressure side of the valve, the arrow direction of the valve body after the valve is opened, the flow direction of the medium.
3) The valve should be regularly used in all sports areas filling oil.
4) After the valve is used for a long time, the packing should be replaced and the packing should be replaced in time. The bolts of the packing gland should be tightened evenly and should not be pressed into a skewed state so as to avoid bumps hindering the movement of the valve stem or causing leakage.
Knife-type gate valve used in the process of coal-washing plant, the use of good results, easy installation and maintenance workers, the maintenance of labor intensity is low, the use of the process is mainly caused by serious wear and tear of the gate valve leakage, lax, five or six months Need to complete the replacement valve. Improving the material of the valve body or improving the structure of overcurrent components in the gate body and improving the service life of the gate valve in the pipe with wearing medium are the hopes of the majority of users.