US2674260A

US2674260A - Water relief valve

Info

Publication number: US2674260A
Application number: US143947A
Authority: US
Inventors: Marquis O Thrush
Original assignee: H A Thrush & Co
Current assignee: H A Thrush & Co
Priority date: 1950-02-13
Filing date: 1950-02-13
Publication date: 1954-04-06
Anticipated expiration: 1971-04-06

Description

April 6, 1954 o, THRUSH 2,674,260

WATER RELIEF VALVE Filed Feb. 13, 1950 FIG. 1 1 FIG. 2

, 21 1s 2h, 20 MMMQMWHI lnl'" i MW I 2% "W {I jjf 1 i 13 4 M H 4 FIG- 6 23 FIG- 3 42 2 wt 1 f :0 W

ll/H! Patented Apr. 6, 1954 WATER RELIEF VALVE Marquis 0. Thrush, Peru, Ind., assignor to H. A. Thrush & Company, Peru, Ind., a corporation of Indiana Application February 13, 1950, Serial No. 143,947

4 Claims. 1

This invention relates to a water relief valve and more particularly to a relief valve for use on hot water heating boilers which will relieve excess water pressure or steam which may be generated in the top of the boiler and will close without losing the entire amount of pressure which has been developed.

Heretofore, steam relief valves or pop valves have been constructed to provide additional lifting surface for rapid operation of the valve after the valve once opens and various means have been provided for relieving pressure which may build up under the additional lifting surface due to seepage through the primary valve seating surfaces, but these devices have not been adapted to use on hot water boilers and when once open these valves will leak until all pressure has been dissipated.

An object of this invention is to provide a water relief valve specifically designed for use on hot water boilers which will overcome the disadvantages enumerated and provide a simple inexpensive valve which will close without losing the entire amount of pressure developed in the boiler.

A further object of the invention is the provision of a water relief valve which will open at the pressure for which it is set, and due to the provision of a secondary valve disc will open ra idly to the wide open position, and, when the excess pressure has been relieved, will close tight after a relatively small pressure drop below the pressure for which the valve has been set.

Another more specific object of the invention is the provision in a valve of the type described above having a secondary valve disc or shroud ring with a depending peripheral flange or skirt and a plurality of weeping glands through the flange or skirt portion, preferably in the form of grooves located on the lower surface thereof, or the glands may be formed in the outer edge of the valve seat.

The present valve has been designed to comply with the present A. S. M. E. code which requires substantially that a relief valve be designed and constructed with metal seats as well as metal discs. It has always been impossible to manufacture such a valve which will be satisfactory for the reason that they could never be shut off tightly after they once open. This type of valve has been used for years in connection with steam boilers but has never been successful with hot water boilers.

The only valves previously successful with hot Water boilers were composite valves which would close tightly with only 1 or 2 p. s. 1. loss in pressure. It has been attempted for years to devise a valve with metal seat and disc which would perform up to this standard but it was only with the perfection of a valve as embodied in the present invention that satisfactory results have been obtained with an all metal hot water relief valve which would close without losing the entire pressure developed within the boiler.

The water relief valve of the present invention includes a valve seat, a primary valve disc seating against the internal peripheral edge of the valve seat and a secondary valve disc of substantially greater area and provided with a depending peripheral flange which is arranged for seating engagement with the beveled outer peripheral edge of the valve seat, the latter being a slightly lesser tight fit than the seating of the primary valve. The peripheral flange is provided with weeping glands in the form of very shallow grooves which will relieve pressure which might tend to build up between the primary and secondary valve disc due to seepage between the primary valve disc and its seat.

Further objects and advantages of the invention will be apparent from the following description taken in conjunction with the drawings, wherein:

Fig. 1 is an elevational view of a water relief valve illustrating one preferred embodiment of the present invention.

Fig. 2 is a vertical sectional view of the valve shown in Fig. 1.

Fig. 3 is a sectional view taken on line 33 of Fig. 2.

Fig. 4 is a sectional view taken on line ll of Fig. 2.

Fig. 5 is an enlarged fragmentary view showing the valve seat and secondary valve disc in elevation.

Fig. 6 is a sectional view taken on line 6-6 of Fig. 5.

Referring now to the drawings in detail a bushing III has polygonal external surfaces and is threaded internally adjacent the bottom portion for screwing onto a suitable fitting, not shown, which would normally be positioned adjacent the top of a hot water heating boiler.

The bushing Ill is also provided with external threads adjacent the top thereof for engagement with threaded opening I! in the valve body Valve body I2 is also provided with a threaded opening 13 for engagement with a suitable conduit for carrying the water and/or steam to any convenient outlet.

The bushing I is further provided with an internally threaded opening M for receiving valve seat I 5.

Valve body l2 has a threaded opening l6 centrally located at the top for engagement with an adjustable bushing I! through which extends a valve stem l8.

An operating lever I9 is retained on the upper forked end of the valve stem l8 by a cotter pin 20, and is further retained in position by the guide lugs 2|.

The spring cap 22 i loosely mounted on valve stem l8 below bushing l1 and engages the upper end of coil spring 23.

The lower end of coil spring 23 engage in a peripheral recess on the upper surface of a valve disc or shroud ring 24 which is, provided with a depending peripheral flange or skirt 25 having shallow grooves or weeping glands 26 on the lower surfaces thereof at diametrically opposite points. While this embodiment of the invention has been shown as having two diametrically op osed weeping glands, it is obvious that 1, 3 or more may be provided depending on the particular design and conditions of service.

Valve disc 24, as shown in Fig. 6, is provided with an axial bore 2.! through which extends the valve stem l8 and an enlarged axial bore 23 which receives the enlarged head 29 provided on the lower end ofthe valve stem IS.

The enlarged axial bore 28 also receives at its lower end a cylindrical projection 30 on the upper surface of the primary valve disc 3| which is press fitted or otherwise suitably and fixedly secured in the enlarged bore 28. As is clearly shown, particularly in Fig. 6, a space i provided between the upper surface of the cylindrical projection 36 and the lower surface of enlarged head 29. which permits a limited movement of the enlarged head 29 within the enlarged bore 28.

The primar valve disc 31 is provided with a frusto-conical seating portion 33 which engages the internal peripheral seating edge of the valve seat l and a conical nose 3.4 which will help to align the valve disc in proper seating engagement with the valve seat after it has been disengaged by excessive pressure. As is clearly shown in Fig. 6 the valve seat is provided with a beveled outer peripheral seating edge 35.. The internal peripheral edge of the skirt 25 engages. the seat portion 35 with a slightly less pressure than the pressure between the seat portion 33 of the valve disc 3| when the latter is in sealing engagement with the sear, l5.

In the preferred form of the invention the internal diameter of the skirt 25. is slightly larger than the external diameter of the valve seat E5 to form a close sliding fit, and the lower surface of the skirt extends slightly below the beveled edge 35 so that the weeping glands 26 form the only appreciable outlet to relieve pressure which may build up in the space 36 between the primary and secondary valve discs. Note that due to the curved formation of the shallow grooves which form the Weeping glands 2B the area of the opening is very gradually reduced in size as the valve closes towards tight seating engagement. The fluid in space 36 will provide a slight cushioning effect during closing of the valve but due to provision of the weeping glands 26 will not prevent tight closure thereof.

In the operation of the device the relief valve is screwed onto a suitable fitting on the hot water heating boiler and is adjusted to relieve the pressure within the boiler at any-desired pressure. When the pressure reaches, for instance 30 p. s. i., the total pressure against the valve disc 3| will be sufiicient to overcome the force of spring 23 and start the valve opening. The pressure then exerted against the much larger area of the secondary valve disc 24 will create a force more than twice that exerted by the valve spring and will cause an extremely rapid operation of the valve to the wid open position. After sufiicient water and/or steam pressure has been relieved from the boiler and dispersed through a suitable conduit, not shown, connected to the opening I 3 the valve will return to its normally closed position with the fluid in space 36 forming a cushion as described above.

Any fluid seeping past the primary valve disc 3| due to thermal expansion or seepage through the valve seat will not build up a pressure against the valve disc 34, but will be relieved by the weeping glands 26, and only when a rapid rate of expansion occurs, or when there is a sudden thrust due to high pressure against the valve disc 3! will the valve open to its wide open position.

In the instance cited above, where the valve is set to maintain the boiler pressure at 30 p. s. i., the actual drop in pressure after the valv has opened wide and closed tight will only be in the order of 4 to 5 pounds. Results of this nature have previously been unobtainable with a metal valve disc and a metal valve seat, since other valves designed for steam will leak until all the pressure has been dissipated, or will not operate satisfactorily in other respects.

It will be obvious to those skilled in the art that various changes may b made in this invention without departing from the spirit and scope thereof and therefore the invention i not, limited by that which is shown in the drawings and described in the specification but only as indicated in the appended claims.

What is claimed is:

1. A pressure relief valve for use on hot water boilers comprising a valve casing having an inlet and an outlet, said inlet being provided with a hollow cylindrical valve seat having a beveled outer peripheral edge, a primary valve disc having a frusto-conical seating surface engaging the inner peripheral edge of said valve seat, a secondary valve disc fixedly mounted on said primary valve disc and having a, depending peripheral flange spaced outwardly from said primary valve disc and in concentric relation therewith, said flange having an internal diameter slightly larger than the external diameter of said valve seat to provide a close sliding fit and having its bottom surface positioned slightly below said beveled edge when said primary valve disc is in tight seating engagement with said valve seat, weeping glands consisting of shallow concave grooves formed in said lower surface, said secondary valve disc having a bore extending axially therethrough with an enlarged lower portion, a valve stem having an enlarged head slidably mountedin said bore with said enlarged head positioned in said enlarged lower portion, said primary valve disc having a projection fixedly secured in said enlarged lower portion and providing a space between said projection and said enlarged head, and means resiliently urging said valve discs toward said valve seat.

2,. A pressure relief valve for use on hot water boilers comprising a hollow cylindrical valve seat having a beveled outer peripheral edge, a primary valve disc having a tapered seating surface engaging the inner peripheral edge of said valve seat; a secondary valve disc fixedly mounted on said primary valve disc and having a depending peripheral flange spaced outwardly from said primary valve disc and in concentric relation therewith, said flange having an internai diameter slightly larger than the external diameter of said valve seat to provide a close sliding fit and having its bottom surface positioned slightly below said beveled edge when said primary valve disc is in tight seating engagement with said valve seat, weeping glands consisting of shallow grooves formed in said lower surface, said secondary valve disc having a bore extending axially therethrough with an enlarged lower portion, a valve stem having an enlarged head slidably mounted in said bore with said enlarged head positioned in said enlarged lower portion, and said primary valve disc having a projection fixedly secured in said enlarged lower portion and providing a space between said projection and said enlarged head.

3. A valve comprising a valve casing, a valve seat having a closed periphery mounted in said casing, a primary valve disk tapering from an outline larger than. the inner periphery of said valve seat to a reduced outline smaller than said periphery for penetration of the smaller outline into said valve seat for guiding the primary disk into seating relation and a secondary valve disk supporting said primary valve disk and positioned on the side of said primary disk away from said seat and having a depending peripheral flange portion with an inner peripheral outline corresponding to the outer peripheral portion of said seat, one of said portions having a bevel for guiding said secondary disk, and grooves in at least one of the contacting surfaces of said portions extending to the lower extremities thereof providing communication between the casing and the space between said primary and secondary valve disks for completely draining condensation therefrom, said primary valve disk being replaceable, and means for supporting said secondary valve disk on said casing for movement toward and from said valve seat and spring means between said valve casing and said secondary valve disk for urging said valve disks to closed position.

4. A pressure relief valve comprising a valve body having an inlet and an outlet with a partition therebetween, a hollow cylindrical valve seat mounted in said partition providing communication between said inlet and outlet, at primary valve disk having a tapered portion engaging the inner peripheral edge of said valve seat, a secondary valve disk fixedly mounted on said primary valve disk and having a depending peripheral flange spaced outwardly from said primary valve disk and in concentric relation therewith, said flange having an internal diameter slightly larger than the external diameter of said valve seat for slidingly receiving the exterior of the valve seat and having its edge appreciably overlapping said valve seat when said primary valve disk is in tightly seated engagement with said valve seat, one of said flange and said valve seat being provided with a bevel for guiding the primary and secondary valve disks to proper seating position, and grooves in the contacting portion of one of said flange and valve seat for the passage of liquid, a valve stem mounted in said body for movement toward and from said seat with the secondary valve disk loosely mounted on the end of said valve stem adjacent said valve seat to permit slight adjustments thereof, and means to move said valve disks to seating relationship and means for moving said valve disks away from said valve seat to permit the passage of fluid between said inlet and said outlet.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 207,820 Richardson Sept. 10, 1878 283,146 Richardson Aug. 4, 1883 297,00? Richardson Apr. 15, 1884 328,840 De Witt Oct. 20, 1885 432,140 Kilborn July 15, 1890 674,675 Fernald May 21, 1901 773,641 Hayden Nov. 1, 1904 1,660,382 Hopkins Feb. 28, 1928 2,490,219 Kmiecik Dec. 6, 1949