brake-valve. In order that the feed valve may be correctly placed, in the No. 6 equipment, the new, crossedpassage pipe bracket has a lug cast upon it that interferes with the attachment of the feed valve unless it is placed right-side up.

The improvements in the B-6 FEED VALVE permit charging to the regulated pressure somewhat quicker, and maintaining the pressure more accurately than the old style did, under the variable conditions of short and long trains, and of good and poor maintenance. Also, the regulation can be quickly and accurately changed from 70 pounds to 110 pounds brake-pipe pressure, or the reverse, by turning the hand wheel until the pin strikes the opposite stop; or any other pressures as the minimum and maximum can be used, by adjusting the stops to secure the desired amount.

Figs. 42 and 43 are diagrammatic views of the FEED VALVE and PIPE BRACKET, having the ports and operating parts in one plane to facilitate description; and to simplify description the direct passage pipe-bracket is represented. The names of the parts shown in the diagrams are as follows: 2, VALVE BODY; 3, PIPE BRACKET; 5, CAP NUT; 6, PISTON SPRING; 7, PISTONSPRING TIP; 8, SUPPLY-VALVE PISTON; 9, SUPPLY VALVE; IO, SUPPLY-VALVE SPRING; II, REGULATINGVALVE CAP; 12, REGULATING VALVE; 13, REGULATING-VALVE SPRING; 14, DIAPHRAGM; 15, DIAPHRAGM

RING; 16, DIAPHRAGM SPINDLE; 17, REGULATING SPRING; 18, SPRING BOX; 19, UPPER STOP; 20, LOWER STOP; 21, STOP SCREW; 22, ADJUSTING HANDLE.

The feed valve consists of two sets of operating parts, the supply (upper), and regulating (lower). The supply parts, which control the flow of air through the valve, consist of the supply valve 9 and its spring 10, the supply-valve piston 8 and its spring 6. The regulating parts consist of the regulating valve 12, regulating-valve spring 13, diaphragm 14, diaphragm spindle 16, regulating spring 17, and regulating handle 22.

Referring to Fig. 42 in which the feed valve is represented in the OPEN POSITION, main-reservoir air enters through port a,a to the supply-valve chamber B, forces supply-valve piston 8 to the left, compresses piston spring 6, and causes the port in supply valve 9 to register with port c in the seat; this permits air to pass through ports c and d to the feed-valve pipe at FVP, the pressure of which flows through port e to diaphragm chamber L.

It will be observed that no packing is used in piston 8, as a certain amount of air leakage past it is desirable, and necessary to the proper operation of the valve; air feeding by the piston to the left can not accumulate in chamber G above feed-valve pipe pressure at this time, for regulating valve 12 is open and connects chamber G to the feed-valve pipe, through passage h, port K,

FIG. 43.-Diagram of B-6 Feed Valve. Closed position.
Connections: See Fig. 42.

Copyright, 1909, by The Norman W. Henley Publishing Co.

DELIVERY

chamber L, and passage e, d, d. Regulating valve 12 is held open by the force of regulating spring 17 against the center of the diaphragm 14, upon which the regulating valve bottoms.

When the air in the feed-valve pipe reaches the pressure at which the feed valve is adjusted-say 70 pounds -its power upon the diaphragm in chamber L overcomes the pressure of regulating spring 17, which is then further compressed (refer now to Fig. 43, CLOSED POSITION), and this permits the small spring 13 to drive the regulating valve 12 to the right until it seats, closing port K and thus cutting off communication between chamber G and the feed-valve pipe; the feed of main-reservoir air from chamber B by piston 8 continues, and the pressure in chamber G quickly becomes equal to that of chamber B; the air pressures on both sides of piston 8 now balancing each other, piston spring 6 forces the piston and supply valve 9 to the right, closes port c and stops the flow of air to the feedvalve pipe.

When the feed-valve-pipe pressure begins to lessen, the regulating spring, 17, again the stronger, unseats valve 12, and the pressure of chamber G equalizes with that of the feed-valve pipe; spring 6 is of very light tension, and the drop of pressure in chamber G results in piston 8 again being forced to the left by mainreservoir pressure, supply valve 9 is opened and the