Slide-valve Cal′cu-lat′or.
Caldwell's slidevalve calculator is a table with vertical, radial, and circular lines, and a revolving templet, giving all calculations relating to the action of the slide-valve. The following points may be deduced by its use, being read off at sight:— 1. The proper travel of valve to produce certain results. 2. The proper lap to cut off at given part of stroke. 3. The proper lap to exhaust at given part of stroke. 4. The proper lap to cushion at given part of stroke. 5. The proper lap to cut off equal on each side of piston. 6. The proper lap to exhaust equal on each side of piston. 7. The proper lap to cushion equal on each side of piston. 8. The proper width of exhaust port to prevent back pressure. 9. The proper lead to give the valve. 10. The proper amount of opening for admission of steam. 11. The position of eccentric on shaft. 12. The relation of valve to piston at every part of stroke. These points are ascertained at sight.Sliding-cover engine. |