Butterfly valves are devices used to interrupt and restore fluid flow in pipelines and piping systems. By placing the shut-off device in the intermediate position, it is possible to regulate the flow.
Butterfly valves are applicable for operating pressures up to 40 (bar), temperatures up to 250 (° C), on request and more, have a compact design and low flow resistance, good controllability, remote control and installation in any position and easy handling and maintenance.
Thanks to these characteristics, butterfly valves are most widely used in plants for the production, preparation and distribution of drinking water, in irrigation plants, in water cooling devices, in power plants, in heating and air conditioning systems, in compressed air installations, in plants for pneumatic transport and distribution of natural gas, for a large number of processes in the chemical, food and paper industries and other areas of economic activity.
Butterfly 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 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.
The housing and the shut-off body of the butterfly valves are made of structural steel by welding, and the shafts are 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 sealing elements depends on the pressure and temperature for which the butterfly seals are designed. Sealing elements for temperatures up to 80 (° C) are made of EPDM, and for temperatures up to 150 (° C) of special EPDM.
The primary sealing of butterfly valves for temperatures up to 250 (° C) is performed through a sealing package made in the form of a sandwich consisting of rings made of stainless steel and seals, and the secondary sealing is achieved using seals and graphite braid.
Full specification find below