US1970937A

US1970937A - Safety valve

Info

Publication number: US1970937A
Application number: US314868A
Authority: US
Inventors: William A Jones
Original assignee: Babcock and Wilcox Co
Current assignee: Babcock and Wilcox Co
Priority date: 1928-10-25
Filing date: 1928-10-25
Publication date: 1934-08-21
Anticipated expiration: 1951-08-21

Description

s- 1934- w. A. JONES 1,970,937

SAFETY VALVE Filed Oct. 25, 1928 INVENTOR BY W ATTORNEY 120 'boiler.

Patented Aug. 21, 1934 UNITED PATENT e- ICE 1 SAFETY VALVE v William'A. Jones, LV Vesterleigh, Staten Island,

N. 31., assignor toThe Babcockt Wilcx Company, Bayonne, N. J., 'a corporation of New I Jersey "Application October v25, 1928, Serial m. 314,868

211 Claims.

through an illustrative embodiment of the invention, and Fig. 2 is a section along the line 22 of Fig. 1. In the drawing reference character 1 indicates an inlet into a valve casing which inlet is connected to the superheated steam space of the A waste steam outlet leading to the atmosphere is indicated at 2. A valve seat '3frn be screwed into place inside the casing as indi cated at 3, and a valve disc 4 is seated upon the same. The valve-disc 4 is provided with a stem 5 that passes through 'a guide '6 which'guide may be made integral with the valve seat3. Ajpi'ston 7 is attached to the lower-end of the valve stem 5, for example,-by screwingthe same to thethreaded end 7 of the valve stem 5. The piston 7 fits in a cylinder 8 inside the casing, and an opening or bleeding orifice 9 is provided through the side wall of the cylinder. An opening 10leads through the casing into the lower endof the cylinderB and a pipe 11 connects the opening 10 to the outlet side of a satiu'ated steam safety valve a on the boiler.

A closure 12 is provided at the upper end of the valve casing and carries a central projection 13 that operates as a stop to limit the :e'xtento'f travel 40 of the valve disc 4. The space 'l'is'connectedt'o the inlet 1 and extends above the valve'disc 4. This space is therefore at all times filled with superheated steam.

The operation is as follows: Steam from the .4-5 superheater passes through the inlet land surrounds the valve disc 4, thus pressing this disc in place against its seat 3. When the saturated steam safety valve opens the steam therefrom passes through the pipe 11 and opening 10 into 5 the cylinder 8, thus raising the piston '7 and lift Due to the fact that the saturated (olden-"53) through the 'superheater, the pressure'of the saturated "steam 'in the cylinder '8 will liftthe valvedisc 4 against the superheated s'team'pres sure when'the effective areas of the piston'7 'an'd a the valve disc 4 are equal to each other. It is 60 apreferable however, to make'the area of the-pisiton 7 somewhat greater than the area of the valve disc 4 to make it certain that the saturated steam pressure will open the valveaga'ins't the pressure of the superheated steam and overcome U the weight of the valve as well as the friction.

The projection 13 limits the distance to which the valve disc 4'can'beli'fted. The point at which the projection 13 stops the disc 4 is such that the lower edge of the piston 7 will uncover the bleeding orifice 9 and permit saturated steam to 'pass out-gradually. When a sufficient amount of s'uperheated steam has escaped to lower the saturated steam pressure to the point where it issa fe the saturated steam safety valve which discharges into inlet "ll closes. The entrapped saturated "steam in the cylinder 8 escaping through the bleeding hole9 lowers the pressureinthe cylinder sufliciently to cause gravity, together with" the pressure of the superheated steam, to close the '39 valve disc 4 against its seat 3. The superheat escape of superheated steam is thus shutoff and since the saturated safety valve had already closed-no more steam will escape from the boiler.

I claim:

1. 'In a safety valve for a steam system 'con- 'taining superheated and saturated steam, means subjected to the operating influence of saturated steam only when such saturated steam is at a predetermined pressure for exhausting the su- 99 perheated steam from said system, and means to permit cutting off the exhaust of the superheated steam when the pressure of the saturated steam has fallen below said predetermined limit, said last named means including an orifice permitting the exhaust, of saturated steam while the valve remains open.

2. In a safety valve for a steam boiler, means to utilize'the difference in pressure between superheated and saturated steam to operate said valve and exhaust superheated steam when the pressure ofsaid saturated steam exceeds a predetermined limit, said means including a pair of valve discs connected by a valve stem with said discs acted upon by the saturated steam and superheated steam respectively in opposition to each other.

3. In a safety valve for a steam boiler that produces saturated steam and superheated steam, a valve disc connected by a steam to a second mined pressure of the saturated steam has been reached, and means to permit'closing said valve when the saturated steam pressure has fallen below a predetermined limit, said last named means including an orifice permitting the escape of saturated steam.

4. A safety valve for steam boilers producing saturated and superheated steam, a fluid pressure actuated piston, a pressure chamberron one side of said piston for saturated steam, and a chamber on the other side thereof for superheated steam, a safety valve actuated by satu-' rated steam pressure to place the said saturated,

steam chamber under boiler pressure on the opening of said last named valve, whereby the piston is moved to release superheated steam.

5. In-a safety valve for a-steam system containing superheated and saturated steamymeans to permit the escape of the superheated steam from the system by subjecting said valve to the pressure of the saturated steam of said system only when said saturated steam has reached a predetermined pressure.

6. In a safety valve for a steam system containing superheated and saturated steam, means to permit the escape of the superheated steam from the system by subjecting said valve to the pressure of the saturated steam of said system only when said saturated steam has reached a predetermined pressure, and means to relieve the valve of the pressure of said saturated steam and thereby permit its closure when the pressure of said saturated steam has fallen below a pre determined limit.

7. In a steam superheater boiler, a superheated steam relief valve normally maintained closed by the pressure of superheated steam, and a pressure controlled boiler valvefurnishing motive power to overcome the superheated steam pressure for moving said relief valve to the open position.

, 8. In a steam superheater boiler, a difierential piston superheated steam relief valve normally maintained closed by the pressure of superheated steam, a pressure controlled boiler valve furnishing motive power to overcome the superheated steam pressure for moving the relief valve to the open position, and means for discontinuing the motive power furnished by the boiler valve when the steam pressure in the :boiler has dropped to a predetermined value.

9. A superheated steam safety valve for ,a steam superheater boiler, comprising a superheated steam exhaustport, a valve member cone trolling said port, means for normally subject ing said valve member to the pressure of super-- heated steam exerted thereon in a direction tending to hold said valve member in its portclosing position, and means for subjecting said valve, member to saturated steam at a higher pressure than the superheated steam whenever the saturated steam pressure in the boiler exceeds a predetermined value and exerted thereonin a direction tending. to move said valve member away from its port-closing position, the areas acted upon by said pressures being so proportioned that said valve member will be rapidly 7 moved away from said port-closing position whenever said saturated steam pressure becomes effective. I

10. Asuperheater steam safety valve for a steam superheater boiler, comprising a superheated steam exhaust port, a valve member controlling said port, means for normally subjecting said valve member to the pressure of superheated steam exerted thereon in a direction. tending to hold said valve member in 2 its port-closing position, means for subjecting said valve member to saturated steam at a higher pressure than the superheated steam whenever thesaturated steam pressure in theboiler exceeds? a predetermined value and exerted thereon in a direction tending to move said valve member away from its port-closing position, the areas actedupon by said pressures being so proportioned that said valve member will berapidly moved away from said port-closing position whenever said saturated steam pressure becomes effective, and means for relieving said valve member of said saturated steam pressure when the saturated steam pressure in the boiler subsequently drops below said predetermined value.

11. A superheated steam safety valve for a steam superheater boiler, comprising a superheated steam exhaust port, an exhaust passage connected to said port, a valve member controlling said port, means for normally subjecting said valve member to the pressure of superheated steam exerted thereon in a direction tending to hold said valve member in its portclosing position, meansfor subjecting said valve member to saturated steam at a higher pressure than the superheated steam whenever the saturated steam pressure in the boiler exceeds a predetermined value and exerted thereon in a direction tending to move said valve member away from its port-closing position, the areas acted upon by said pressures being so proportioned that said valve member will be rapidly moved. away from, said port-closing position whenever said saturated steam pressure becomes efiective, and means for relieving said valve member of said saturated steam pressure when the saturated steam pressure in the boiler subsequently drops below said predetermined value comprising afsat'urated steam orifice opening to said exhaust passage. v WILLIAM A. JONES.

CERTIFICATE 9F CORRECTION.

Patent Ne, 1,970,937. August 21, 1934.

WILLIAM A. JONES.

it is hereby certified the: erm'r swears in the printed specification of the above numbered patent requiring eerreciiim as follows: Page 1, line 81, strike out the word "'superheat"; and line 116, eiainrZi, for "steam" read stem; and that the said Letters Patent should ire read with inese corrections therein that the same may conform to the record or the case in the Patent Office.

Signed and sealed this 5th day of March, A. I). 1935.

Leslie Frazer (Seal) Acting Commissioner of Patents;