Butterfly check valves are protective devices in pipelines and pipe systems for the transport and storage of liquid fluids. They are used to prevent the return flow of the working fluid, and the action of the butterfly check valves is automatic. They are most widely used in plants for obtaining, preparing and distributing water, in wastewater treatment plants, in utility facilities, in irrigation systems, in various plants of the chemical and petrochemical industry and in energy plants.
Butterfly check valves allow fluid flow in only one direction, so during installation, care should be taken that the direction of the arrow on the butterfly check valve housing corresponds to the direction of movement of the working fluid in a particular pipeline.
Butterfly check valves are made with a shut-off body that is double eccentric, and rotates with a shaft at the left end of which, viewed in the direction of flow, a lever with a counterweight is placed. The role of the counterweight is to start the shut-off body before the speed of the working fluid is equal to zero, and thus reduce the amount of fluid that will return through the valve and reduce the magnitude of the inertial force. The thrust ring on the valve body is welded with a suitable stainless steel electrode, and the sealing is achieved through a rubber ring located along the circumference of the shut-off body which rests on the finely polished surface of the thrust ring.
Butterfly check valves are made with installation lengths that meet the standards SRPS M.C5.005 – F4 and DIN 3202 – F4, and the connection dimensions of the flanges are designed according to SRPS M.B6.011 and DIN 2501.
Nominal diameters of butterfly check valves of our product range from DN 150 to DN 1500 (mm), pressures from NP 2.5 to NP 25 (bar), and on request up to 40 (bar), for the highest working fluid temperature up to 150 (° C). ). Butterfly check valves for higher back pressures and larger nominal diameters are equipped with hydraulic damping cylinders to regulate the closing speed, in order to reduce the hydraulic shock and reduce the impact force of the shut-off body on the limiter.
The housing, the shut-off body, the lever and the weight of the butterfly check valves are made of structural steel by welding, and the shaft is made of stainless steel or steel for improvement with sliding surfaces made of stainless steel.
Plain bearings are made of grey cast iron, and the choice of material for the sealing elements depends on the pressure and temperature for which the butterfly check valves are designed. Sealing elements for temperatures up to 80 (° C) are made of EPDM, and for temperatures up to 150 (° C) of special EPDM.
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