Model KM 9901.1 117 (Z35) - Vertical Lift Type Check Valves
Flanged vertical lift-type check valve type KM 9901.1 117 (Z 35) is unidirectional valve designed to prevent from reverse flow of the service fluid. The direction of the fluid flow is marked with an arrow on the valve's body from the bottom to the top, i. e. under the disc. In case the fluid starts flowing back, the disc closes the check valve automatically.
Vertical lift-type check valves are not designed as conventional isolating valves. If permanent tightness of the disc is required, an isolating valve shall be installed into the delivery piping. The service fluid must not contain hard and abrasive particles in form of grains or powders and its chemical composition must not form segregation deposits as this could damage the seating surfaces and bring about heavier untightness or sticking of the disc in the bearings.
The check valves are designed to be used with fluids in groups 1and 2 according to Section 3(1)(a, b) of Decree of the Government No. 26/2003, i.e. water with the exception of potable water, non-aggressive fluids (liquids, gases, vapours, air), oil and oil products, gaseous fuels, inorganic and organic media (acc. to materials used and after an agreement with a manufacturer) and according to the directive PED 97/23/EC. The resistance of the check valve to the fluid and its temperature is limited by the chemical composition of the check valve materials. It is therefore recommended to consult the suitability for the relevant fluid with the manufacturer. Allowable service pressures are in compliance with the pressure-temperature ratings.
The main part of the flanged vertical lift-type check valve is a one-piece body which is made of rolled or forged steel. The body contains an inlet disc guide and an outlet disc guide with plain bearings which are pressed into the body. The pressed-in parts are secured by centre punching. The disc guides are secured in place by the counter-flanges of the piping. The seats of both the body and the disc are usually weld-deposited with austenitic steel of 18/8 CrNi type or Stellite 6 – type of the weld overlay depends on the material composition of the check valve. The disc is lapped with the body seat.
Connection to piping
Overall dimensions are shown in the datasheet. Dimensions according to standards:
- connection according to EN 1092–1
- face-to-face dimensions of individual sizes in pressure classes PN 16, 25, 40, 63, 100, 160, 250, 320 meet the requirements of standard ČSN 13 3048, table 1
- not standardized face-to-face dimensions: – pressure class PN 400
- sizes DN 50 / PN 16–250; DN 300 / PN 16–250
- sizes DN 350, 400 / PN 16–100; DN 50–200 / PN 320
According to EN 12 266–1 as a standard, i.e. shell strength test P10, P11, seat tightness test P12 (water pressure 1,1×PN and air pressure 0,6 MPa), leakage rate A – zero leakage, operability test F20. Standard ČSN EN 13709 specifies that a seat leakage corresponding to leakage rate C according to ČSN EN 12266–1 is allowed in case of test P12. If required by the Customer, additional tests may be performed as well.
Installation, service and maintenance
Vertical lift-type check valve shall be installed in vertical position. As it is a uni-directional valve, the fluid flow shall correspond to the arrow marked on the valve body. When installing the vertical lift-type check valve to piping it should be taken into account the fact that that in the fully open position of the valve the shaft of cone protrudes above the outlet flange by a distance which is equal to the maximum cone lift.
The valve requires no special maintenance or adjustment. If the values of temperature and pressure of the fluid as specified on the valve label are adhered to, the check valve operation is fully automatic.