A foot valve is generally placed at the lower end of the suction pipe of a centrifugal pump to prevent the suction pipe from emptying while the pump is at rest; consequently, when the pump is first started it does not have to exhaust the air from the suction pipe with the result that prompt starting of the pump is secured. Foot valve is particularly use- ful when the suction lift or vertical height of the pipe is considerable.
| Sl. No. | Component Part | Material | Conforming To | Grade |
|---|---|---|---|---|
| i) | Housing, seat discs and disc plates | Grey cast iron | IS : 210-1978* | FG 200 |
| ii) | Hinge pins and disc guide |
a) High tensile bars b) Stainless steel |
IS : 320-1980† IS : 6603-1972‡ |
HT 2 04CrNi10 |
| iii) | Strainers |
a) Grey cast iron b) Galvanized steel |
IS : 210-1978* IS : 277-1985§ |
FG 200 |
| iv) | Disc faces | Vegetable tanned leather (Thickness 3 mm, Min) | IS : 581-1976|| | — |
| Leaded tin bronze | IS : 318-1981¶ | LTB 2 | ||
| Natural rubber (with reinforcement of cotton canvas) | IS : 5192-1975** | Grade 1, Type B | ||
| Synthetic rubber (with reinforcement of cotton canvas) | IS : 7450-1974‡‡ | Grade 1 | ||
| v) | Flange jointing nature |
a) Compressed fibre board or rubber of thickness 1.5 mm, Min. The fibreboard shall be impregnated with chemically neutral oil and shall have a smooth and hard surface. |
IS : 638-1979†† | Type B |
| b) Compressed asbestos fibre | IS : 2712-1979§§ | Grade W/3 |