d. The construction of bushing and hole in partition must be such that a cylindrical shell for use with a packed piston can be interchangeably inserted in its place and secured by the same bolts.
This can readily be arranged and enables a packed piston to be inserted in place of a plunger subsequent to the installation of the pump with a minimum of expense, should this become desirable from change of conditions at any future time.
e. Small transverse grooves cut within the sliding surface of the plunger bushing, with a view to lessen the leakage, are not acceptable.
Although a slight advantage in this respect for clean water, they are a disadvantage on the whole, as dirt catches in them in the ordinary situation and cuts the plungers.
29. Standard Dimensions of Plungers and Plunger Bushings.
a. To bring all these expensive parts to the same standard of weight and bearing surface, the following dimensions are specified as the least that will be acceptable. These are based on a length of plunger which uncovers the bushings one inch at end of nominal stroke.
SOLID BRONZE PLUNGERS AND BUSHINGS.
| Size of Pump. | 500 gal. | 750 gal. | 1000 gal. | 1500 gal. |
|---|---|---|---|---|
| Plunger. | ||||
| Diameter | 7 or 71⁄4-in. | 9-in. | 10 or 101⁄4-in. | 12-in. |
| Length | 17-in. | 17 „ | 18-in. | 24 „ |
| Thickness of transverse partition | 5⁄8 „ | 5⁄8 „ | 3⁄4 „ | 3⁄4 „ |
| Thickness next to partition | 1⁄2 „ | 1⁄2 „ | 5⁄8 „ | 3⁄4 „ |
| Thickness next to end | 5⁄16 „ | 3⁄8 „ | 3⁄8 „ | 1⁄2 „ |
| Number of ribs | 4 | 4 | 6 | 6 |
| Thickness of ribs | 5⁄16 „ | 5⁄16 „ | 3⁄8 „ | 3⁄8 „ |
| Bushing. | ||||
| Length | 7 „ | 7 „ | 8 „ | 10 „ |
| Thickness at end | 5⁄16 „ | 3⁄8 „ | 3⁄8 „ | 1⁄2 „ |
| Thence tapered evenly to a thickness next to bearing of not less than | 1⁄2 „ | 5⁄8 „ | 5⁄8 „ | 3⁄4 „ |
| Thickness at the center bearing not less than | 3⁄4 „ | 3⁄4 „ | 3⁄4 „ | 13⁄16 „ |