Butterfly valves with a rubber coating are most often used as shut-off devices in pipelines for the transport of various fluids. As control devices, they are used when the fluid flow rate is relatively low. Compared to classic devices that have the same function, butterfly valves with a rubber coating have significant advantages.
Simple and compact construction, significantly shorter installation length and lower shutter weight reduce the space required for installation, speed up and facilitate installation, handling and maintenance. The sealing rubber lining eliminates the possibility of contact of the working fluid with the shutter housing and allows the use of standard housing for the flow of different fluids by changing the quality of the lining.
They are used in plants for the transport of drinking, sea, technological, geothermal, waste and other waters, in the chemical and food industry, in the industry of alcoholic and non-alcoholic beverages, as well as for the transport of oil and oil derivatives, air and various acids and gases.
Butterfly valves with a rubber coating are made for nominal diameters DN 50 to DN 800 (mm), for working fluid temperatures up to 80 (° C) and nominal pressures up to NP 16 (bar), with a centric shut-off body.
Nominal diameters of butterfly valves of our product range from DN 80 to DN 3000 (mm), and pressures from NP 2.5 to NP 40 (bar). Depending on the temperature of the working fluid, butterfly valves are made for temperature ranges up to 80, up to 150 and up to 250 (° C).
Butterfly valves for temperatures up to 80 (° C) and up to 150 (° C) are made as single eccentric, and the sealing is achieved through a specially profiled rubber ring, located around the circumference of the shut-off body, which rests on the persistent ring of the housing.
The angle of the thrust ring is determined so as to ensure mutual sealing with minimal frictional resistances between the sealing and thrust ring. Thanks to this, the butterfly valves of our products can be used for fluid flow in both directions, but the direction indicated by the arrow on the housing is preferred.
Butterfly valves for temperatures up to 250 (° C) are made with double eccentricity. The axis of rotation of the shut-off body is located eccentrically in relation to the abutment ring and on the longitudinal axis of the housing, which achieves faster separation of the seal from the abutment ring. This constructive solution reduces the friction between the bearing surfaces, and at the same time creates the possibility of sealing metal to metal.
As a sealing element, a special package sandwich is used, which consists of rings made of stainless steel and seals, and which is fixed to the shut-off body by means of a clamping ring. Sealing is achieved by the sealing package with its conical surface resting on the cone of the persistent ring.
For standard versions of butterfly valves, drives are defined with regard to the nominal diameter, pressure, temperature and the method of control of the pipe system armature. The butterfly actuator drives we use in the standard version are: manual drive by a lever, manual drive through a worm gearbox and electro-mechanical drive.
At the customer’s request, we also supply butterfly valves with pneumatic, hydraulic, and electro-hydraulic drives or with additional elements for remote control.
Butterfly housings with a rubber coating are made of structural steel by welding, and the shut-off body is well provided that the sealing surface of the shut-off body is made of stainless steel.
The shafts are made of stainless steel or steel for improvement with sliding surfaces made of stainless steel, and the plain bearings are made of cast iron. The choice of rubber for the sealing lining depends on the characteristics of the working fluid, but it is most often used in EPDM.
Full specification find below