US2630758A

US2630758A - Antiracing valve for steam-driven feed pumps

Info

Publication number: US2630758A
Application number: US125401A
Authority: US
Inventors: Erich W Henkel
Original assignee: Combustion Engineering Superheater Inc
Current assignee: Combustion Engineering Inc
Priority date: 1949-11-04
Filing date: 1949-11-04
Publication date: 1953-03-10
Anticipated expiration: 1970-03-10

Description

March 10, 1953 w. HENKEL 2,630,758

ANTIRACING VALVE FOR STEAM-DRIVEN FEED PUMPS Filed NOV. 4, 1949 BY P058 10 ae Ii 14 I |U Wfl T67? SUPPLY ER/CH WHEN/(EL INVENTOR.

14 T TOENE Y Patented Mar. 10, 1953 ANTIRACING VALVE FOR.- STEAM-'DRIVEN FEED PUMPS ErichW. HenkeL'Calumet City, 111., assignor to Combustion Engineering-'Super heater,

New York, N. Y.

inc

Application November 4, 1919,.SerialiNo..1'25,41l1

The present invention relates to pumps and particularly to an improved means for preventing racing of a steam driven feed pump when it loses suction.

Steam driven feed water pumps are liable to race or run away in the event that the water side of the pump becomes air bound or the water supply fails due to emptying of the supply tank or disruption of piping connecting the latter to the pump. The invention contemplates the provision of a control valve in the exhaust line from the steam cylinder of a reciprocating feed water pump which is subject to water delivery pressure so that it moves towards closed position on loss of pump suction and builds up a high exhaust pressure that acts to prevent racing of the pump. The invention is also applicable to centrifugal pumps.

In the drawings;

Figure 1 is a diagrammatic view of a pump system embodying the present invention; and

Figure 2 is a sectional view on an enlarged scale of the control valve embodied in the system of Figure 1.

In Figure 1 there is represented a conventional reciprocating feed water pump having one or more steam cylinders I receiving steam through the piping II and discharging exhaust steam through the pipe [2. Water is drawn into the water cylinders I3 of the pump from the supply tank [4 through a pipe [5 and is forced through the pipe IE to a boiler or other point of use.

In accordance with the present invention there is interposed in the exhaust steam line l2 a control valve designated as a whole by the numeral 20 in Fig. l. The exhaust steam enters the valve casing 20 through the pipe l2 and passing through the valve chamber 23 is discharged through a pipe 2|. This flow is subjected to control of the valve member 24 in chamber 23 which in Figure 2 is illustrated as being seated. This valve member 24 has a by-pass port 25 connecting its inlet and outlet sides so that even when the valve 24 is in closed position a small amount of steam may pass to the vent pipe 22. The stem 30 of valve 24 is connected to a pressure responsive diaphragm or bellows 3| located in a chamber 32 that is connected by a pipe 33 with the feed line It; leading from the delivery side of the pump. Thus, the bellows 3| is subjected to the water delivery pressure which acts thereon in a direction to open the valve 24 against the resistance of aspring 34 located within the bellows. A bypass line 36 connecting with the feed line [6 leads back to the water supply tank It and has a re-' '3 Claims. (GI. 103-15") 'stricti'on 3'! therein. This 'by-p'ass is provided to safe-guard the operation of the c'on'trolapparatus against a leaky boiler check valve as at 38. The by-pass also serves the useful purpose of eliminating from the water system any air that may have accumulated when the pump is started after a prolonged period of shut down.

Assuming that the pump is applied to a boiler which carries a normal operating steam pressure of 250 p. s. i. and that the steam flow to the pump through pipe H is regulated automatically by a water regulator which is set to maintain a constant water level in the boiler drum. During normal operation the

anti-racing valve

20, 24 in the pump exhaust line will be held in wide open position by the pump delivery pressure acting on bellows 3i. Inasmuch as the valve member 24 in its open position oifers very little resistance to the flow of exhaust steam, the exhaust steam pressure at the pump will be low or normal. Should a water supply failure at the water end of the pump occur, which in turn will cause the pump delivery pressure to drop below e. g. p. s. i. for which the spring inside the bellows is set, the spring 34 will force the valve 24 to its closed position. The steam leaving the pump must then pass through port hole 25 which will induce a considerable restriction to the steam flow. It follows that the exhaust pressure between valve 20 and pump, cylinder l9 becomes abnormally high. The pump steam side becomes "steam locked, forcing the pump to run at an idling speed as long as there is steam entering the pump until conditions at the pump water end are corrected whereupon a water delivery pressure of above 60 lbs. is sufflcient to open the valve 24 again. The high exhaust pressure at the pump is immediately released and the pump again is prepared to operate at normal.

What I claim is:

1. In combination with a steam operated pump drawing water from a source of supply and introducing it into a feed line provided with a check valve, and an exhaust pipe connected to the steam side of the pump; a control valve in said pipe; means responsive to a predetermined pressure of water delivered by said pump for opening said valve; spring means associated with said valve for moving it to closed position when the water delivery pressure falls below said predetermined value; and a by-pass associated with said exhaust line and valve for permitting escape of steam to enable continued operation of said pump when said delivery pressure falls below said value.

2. In combination with a steam operated pump drawing water from a source of supply and introducing it into a feed line provided with a check valve, and an exhaust pipe connected to the steam side of the pump; a control valve in said pipe; vmeans responsive to a predetermined pressure of water delivered by said Pump for opening said valve; and means operative when said water pressure falls below a predetermined value to act upon said valve so as to restrict the flow of exhaust steam in said pipe and thereby preclude racing of said pump.

3. In combination with a steam operated pump drawing water from a source of supply and introducing it into a feed line provided with a check valve, and an exhaust pipe connected to the steam side of the pump; a control valve in said pipe; pressure responsive means connected to said valve arranged whensubjected to a predetermined pressure to move said valve in a direction to open it; a pipe connecting said feed line to said pressure responsive means for subjecting said means to the delivery pressure of said pump to cause opening of said valve when said pressure reaches a predetermined value; means acting to close said valve; a water return between said feed line and said supply source; and restrictive means in said return line for limiting the flow therethrough.

ERICH W. HENKEL.

REFERENCES CITED UNITED STATES PATENTS Number Name Date 1,077,090 McGowan Oct. 28, 1913 1,863,406 Hudson June 14, 1932 2,250,865 Grifiin July 29, 1941 2,264,753 Henkei Dec. 2, 1941