PRESSURE-RETAINING VALVES 



359 



reducing the pressure from 50 to 15 Ib. proportionately longer. 

 The small vent port chokes the discharge of air so that the 

 weight 4 closes the weight valve at short intervals during the 

 reduction. The restricted opening of the vent port is a valuable 

 feature of this valve. 



HIGH- AND LOW-PRESSURE RETAINING 

 VALVES 



The 15-30 pound, high- and low-pressure retaining valve, 

 shown in Fig. 1, regulates the pressure at 15 and 30 Ib. It is 



FIG. 1 



FIG. 2 



used on 6-in., 8-in., and 10-in., brake cylinders and weighs 

 6J Ib. The piece and reference numbers of the valve and of 

 its various parts are given in the accompanying list. 



PC. No. Ref. No. 



Name of Part 



10,970 Type 15-30 pressure-retaining valve, com- 



plete. 



10,973 Body, complete, includes 5, 6, 7, and 8. 



10,972 2 Body, bushed. 

 10,977 3 Case. 

 11,756 1 Inside weight, complete. 



