ENGINEER'S BRAKE VALVES 147 



same as the C-6 feed-valve except that it will charge to the 

 regulated pressures somewhat quicker and will maintain the 

 pressure more accurately under the variable conditions of short 

 and long trains. It is connected to a pipe bracket located 

 in the piping between the main reservoir and the H-6 brake 

 valve, and is supplied with air from the main reservoir. It 

 regulates the pressure in the feed-valve pipe as well as in 

 the brake pipe in running and holding positions of the H-6 

 brake valve. It has a double-regulation feature, so that it 

 can be quickly adjusted to change the regulated pressure from 

 one standard pressure to another. This feed-valve is inter- 

 changeable with previous types of slide-valve feed-valves and 

 can be attached to the F-6 and G-6 brake valves, thereby doing 

 away with the reversing cock, the extra feed-valve, and the 

 pipes connecting it to the brake valves. 



There is a quick-thread screw on the regulating hand wheel 

 20 that will change the adjustment of the regulating spring 19 

 from 70 to 110 lb., or to other moderate differences of pressure 

 when the wheel is turned. Stops 21 and 22 are split rings that 

 fit around the spring box 15 and are clamped in their proper 

 positions by the screws 23. The regulating spring unseats the 

 regulating valve and determines the pressure to be carried 

 in the feed-valve pipe. When the pressure in the chamber 

 above the diaphragm 17 is less than the tension of the spring 19, 

 the diaphragm is held over against the pressure of the air 

 and the regulating valve is held off its seat. 



When the pressure in the feed-valve pipe reaches the stand- 

 ard desired, the pressure above the diaphragm will overcome 

 the tension of spring 19 and move the diaphragm to the right, 

 allowing the regulating-valve spring to move the regulating 

 valve to its closed position. Spring 13 holds the regulating 

 valve 12 against the diaphragm in open position, and against 

 its seat in closed position. The diaphragm ring 16 makes an 

 air-tight joint with the diaphragm against the valve body, 

 and prevents the escape of air past it into the regulating-spring 

 chamber. 



Regulation of B-6 Feed-Valve. To insure accuracy in 

 regulating, the B-6 feed-valve should be connected with a 

 correct pressure gauge. The regulating hand wheel 20 should 



