Non-return Valve With Counterweight

Description: FEROPLAST NKT Non-return valve with counterweight is made as an irreversible reflective flap that allows fluid flow in the pipeline only in one particular direction and prevents flow in the opposite, undesired direction. It operates automatically as soon as you stop the flow in a certain direction, valve closes and prevents flow in the opposite direction. Movement of the lid from the fully opened position to the closed one is made of the potential energy and the possible pressure of fluid in the opposite direction only enhances the closure. Non-return valve is designed for installation both in horizontal and vertical pipeline. The arrow on the body marks the flow direction in which the valve is open.

Non-return valve with counterweight is installed by connecting with the flanges on the pipeline or a device under pressure. Overall length is the standard one for reflective flap with flanges, line 14 according to EN 558 a.

Advantages of construction: Non-return valve with counterweight is made in a welded structure, flanges are made of structural steel with connecting dimensions according to EN 1092-1 for the appropriate DN and PN, and the body is made of standard seamless steel pipe. The shutter is made of two parts between which there is tightened seal of elastomer, which lies exactly in the conical seat and a well seal. Set of shutter flap is easily maneuverable with horizontal axis that passes through the body. On the horizontal axis there is set leverage with the weight. The shaft is well mounted in a passage (seam) through the body and sealed with a gasket that can be tightened during operation.

Hub with weight lever is pulled to the end of the shaft and its position is determined by the transverse screw (1). The sketch shows the position of the lever with a weight of horizontal (H) and vertical (V) mounting non-return valves, as well as the position of the screws (screw 1 and the position of the lever in a side view indicated by M).

Working conditions:

  • Installation:
    flange connection with standard connecting dimensions of flanges,
  • Nominal sizes:
    DN 100 … DN 500,
  • Nominal pressure:
    PN 6, PN 10, PN 16 and PN 25,
  • Temperature:
    for the EPDM seal, -30°C … +140°C,
  • Operating fluid:
    water or other fluid not aggressive to carbon steel and EPDM,
  • Installation:
    horizontal position with the shaft in the top position, vertical position with a shutter at the bottom. The position of the lever with a weight according to the sketch.

Testing: Each valve is finally tested by pressure according to standard EN 12266-1, P10, P11 (strength and tightness of the housing) and P12 – penetration level A (sealing seats).

Materials: In the basic version, connecting flanges and the shutter are made of carbon steel, the body is of the seamless tube alloy steel, diameter and wall thickness which are standard for the appropriate DN and PN, shaft shutter is made of stainless steel and the seal on the front shutter (flap) is made of EPDM elastomer. Seal the shaft assembly into the housings is made of the profiled EPDM. Whole non-return valve with counterweight is protected on the outside and inside with a plastic coating layer thickness of at least 250 microns.

In the basic version, flanges with a raised sealing surface (type B) and the lever with weight in position for horizontal mounting flap. If during installation requirements for vertical installation occurs, it is necessary to draw the screw (1), rotate the lever on the axle for 90 ° and set screw in the other hole on the shaft (see sketch, position the lever for vertical installation is indicated by V). When ordering, specify on which side the lever should be, looking in the direction of flow.

On demand: Non-return valve can be made with other nominal openings, with other/larger mounting lengths, with other nominal pressures, with another type of sealing surfaces and made of other materials.

Basic dimensions dimensions in mm
DN 100 125 150 200 250 300 350 400 450 500
L 190 200 210 230 250 270 290 310 330 350

The manufacturer has the right to make changes, please contact us for a quote!