Example.
| 45 | inches, length of lever, | |
| 100 | pounds, weight of ball, | |
| Fulcrum, 5 in. ) | 4500 | |
| 900 | ||
| 60 | pounds, weight of valve and lever, | |
| Area of Valve 8 ) | 960 | |
| 120 | pounds, pressure at which valve will blow. |
To find the weight of ball:
Rule.—Multiply the steam pressure by the area of the valve, and from the product subtract the effective weight of the valve and lever, then multiply the remainder by the distance from the valve centre to the fulcrum, and divide the product by the length of the lever.
Example.
| 120 | pounds, steam pressure, | |
| 8 | inches, area of valve, | |
| 960 | ||
| 60 | pounds, weight of valve and lever, | |
| 900 | ||
| 5 | inches, fulcrum, | |
| Length of lever, 45 in. ) | 4500 | |
| 100 | pounds, weight of ball. |
To find the length of lever:
Rule.—Multiply the steam pressure by the area of the valve, and from the product subtract the effective weight of the valve and lever, then multiply the remainder by the distance from the valve centre to the fulcrum, and divide the product by the weight of the ball.
Example.