US627390A - Relief valve - Google Patents

Description

No. 627,390. Patented June 20, I899.

' A. W. CASH.

RELIEF VALVE.

(Application filed Mar. 3, 1899.)

2 Sheets-Sheet I.

(No Model.)

In: NONI! s PETERS 0. Morin mo wAsn uu'rou. n c.

No. 627,390. Patented June 20, I899. A. W. CASH.

RELIEF VALVE.

(Application filed Mar. 3, 1899.; (No Model.) Sheets-Sheet 2.

UNITED STAT S PATENT GFFICE.

ARTHUR V. CASH, OF NEWARK, NEW JERSEY, ASSIGNOR TO THE FOSTER ENGINEERING COMPANY, OF SAME PLACE.

RELIEF-VALVE.

SPECIFICATION forming part of Letters Patent No. 627,390, dated June 20, 1899.

Application filed March 3, 1899. Serial No. 70 7,695. (No model.)

through the'valve and escape to the atmos- In most valves of this class it has phere.

heretofore been the practice to employ some arrangement of levers having weights thereon to resist the fluid-pressure to which the valve is adjusted, and as such weighted valves are liable to operate in an irregular manner, with a chattering, jumping, or hammeringv movement, the weight has been sometimes replaced by a spring to overcome the hammering or jumping of the valve; but in the ordi- 2 5 nary application of such spring to a clapper- Valve there is incurred the disadvantage of requiring a greater fluid-prcssu re to hold the.

valve open sufficiently to pass a large volume than when open to pass a small volume, thus 0 making a material difference in the pressure To over-- with variable volume of delivery. come this disadvantage of the spring as ordinarily applied, 1 have provided what may be termed a compensating arrangement of 3 5 valve-controlling devices, whereby the resisting power of the spring as applied to a clapper-valve is made practically constant, with the result that a constantly-uniform pressure can be maintained in the lower part of the valve -casing, because the valve will freely rise any distance sufficient to allow the escape of any pressure in excess of that desired.

My invention consists in features of construction and novel combinations of parts in 5 a relief or safety valve orback-pressure valve,

as hereinafter described and claimed.

In the annexed drawings, illustrating the invention, Figure 1 is a vertical section of my improved relief-valve. Fig. 2 is a horizontal section of the same.

The valve comprises a lower circular casing 1 and an upper circular casing 2, each made from some hard metal of moderate costsuch as cast-iron, for instance. Between the adjacent edges of these casings there is clamped 5 5 an annular Web 3, which is preferably made of brass, bronze composition, or other soft non-corrosive metal. A dash-pot 4 is supported in a vertically-depending position in the lower valve-casing 1 by means of radial 6o arms 5, connecting with the web 3, which rests in a slight annular recess in the inner rim of the lower casing, where it is tightly clamped and held in position between the said lower casing 1 and the upper casing 2 by means of bolts 6, inserted through annular flanges 7 on said casings. This construction serves the doublepurpose of holding the web 3 and central dash-pot 4 in proper position and of also forming a tight joint between the lower and upper casings of the valve, so as to prevent escape of steam or other fluid pressure at the joints of the said clamped-together web and casings.

The valve proper consists of an inverted 7 dish-shaped clapper 8, having a central depending hollow stem 9, which is open at the top and closed at its lower end, except for a small passage 10 at one side. This hollow valve-stem 9 is fitted to slide freely in the vertically-arranged dash-pot 4 and is provided with circumferential grooves 11 at each end. On the under side of the clapper 8 there is a strengthening-ring 12 and a number of radially-arranged ribs 13, that further strengthen the device. The peripheral portion of the clapper Sis turned downward and normally rests upon an annular valve-seat 14, that is provided on the annular web 3. The length of the hollow valve-stem 9-is such that 0 it does not reach the bottom of the dash-pot at, and so when the valve is seated there is left below the stem 9 ashallow space 15, which will ordinarily be filled, through the small passage 10, with water of condensation from 5 the hollow valve-stem 9, it being understood that this valve is to be arranged and operated in a vertical position.

The valve 8 is normally held down on its seat 14: as against fluid-pressure on its under surface by means of a vertically-arranged stud or post 16, having its enlarged rounded lower end resting centrally in the bottom of the hollow valve-stem 9 and its upper rounded end in contact with the concaved or inverted cup-shaped end of a yoke-shaped lever 17, the outer end of which is fulcrumed on a pivot pin or rod 18, that is supported longitudinally at one side of the upper valve-casing. This yoke or lever 17 is forced downward at all times by a diagonally-arranged spring 19, having at one end a widened scalebearing washer 20, restingin a pocket or hearing 21 on the yoke or lever. The outer or upper end of the spring 19 is provided with a washer 22, having a central hole or recess, into which fits the end of an adj usting-screw 23, that is threaded into and projects from the upper casing of the valve. By means of this adjusting-screw 23 there can be given to the spring 19 the required compression to resist, through the yoke 17 and post 16, any predetermined pressure against the valve or clapper. V

In order to hold the valve 8 open or lifted when no back pressure is required, it is preferable to connect the lever or yoke 17 with the valve'S through a yoke-piece 24, that is bolted to the valve in a horizontal position above the same. The bifurcation of the yoke 24 is arranged toward the end of the lever 17, and the ends of said yoke 2% are extended downward to form lugs 25, that rest on the top of the valve 8 and through which the vertical attaching-bolts 26 are passed. The end of the yoke-lever 17 is provided on opposite sides with trunnions 27, that are engaged under the ends of the yoke-piece 24, so as to have a lifting action thereon when the valve Sis to be held open regardless of the pressure or absence of pressure at its under side. For the purpose of acting on the lever 17, so as to cause it to lift the valve 8 and hold it at any required elevation, the pivoted end of said lever is provided with a downward extension 28, arranged to aiford a bearing for the endof an adjusting-screw29, that is threaded through an adjacent portion of the valvecasing. By causing the inner end of this screw 29 to bear forcibly against the lever extension 28 and adjusting the screw inward a suflicient distance the lever 17 may be made to lift the valve 8 and hold it at any elevation desired when no back pressure is to be regulated or controlled. The inward adjustment of the screw 29 to a suflicient distance not only overcomes the compression of the valve-closing spring 19, but lifts the valve from its seat, holds it open, and thus permits the passage of any pressure that might be insufficient to raise the valve against the action of the spring.

The valve is secured to a suitable receiver or to a system of piping by means of bolts passed through the flange 30 011 the lower end of the lower casing 1, so that the steam or other fluid-pressure will enter at the inletport 31 and fill the space below the valve 8, remaining confined there until a sufiicient pressure is accumulated to overcome the resistance or compression to which the spring 19 has been adjusted and which is acting through the lever 17 to hold the valve normally closed. Any excess of pressure above a predetermined amount will lift the valve 8 against the resistance of the lever 17 and spring 19 and will then pass freely to the atmosphere through the exit-port 32 of the upper casing 2, around which port there is an ann ular flange 33, to which a suitable escapepipe may be bolted.

It will be observed that the lever 17 and spring 19 are so arranged that when the valve or clapper 8 is closed down onto its seat 14, as represented by full lines in Fig. 1, the leverage of the compression-spring 19 on the lever 17 is about equal to the distance from a to a, and when the valve is in its highest position or open to the fullest extent required, as indicated by the dotted contour line b, the spring 19 will have been compressed an amount equal to distance 0 c, which will have considerably increased its stored power; but in the meantime its leverage has been decreased from distance a a to distance d d, and thus its actual resistance through lever 17 and post 16 to valve 8 will have been maintained practically constant, the relative arrangement of the lever 17 intermediate the valve and its spring being such as to compensate for varying degrees of compression in the spring through varying positions of the opehing and closing valve. Thus by means of the compensating lever 17 the resisting power of the spring 19 as indirectly applied to the "alve 8 is equalized or made practically constant, with the result that no greater fluidpressure is required to hold the valve open sufficiently to pass a large volume than when open to pass a small volume, and as the valve will freely rise any height required to permit escape of any pressure in excess of that desired there is easily maintained a constantlyuniform pressure in the lower valve-casing.

The Valve operates readily without hammerin g, jumping, or any irregular movement, and by means of the communication aflorded by the passage 10 between the dash-pot 4 and hollow valve-stem 9 the water of condensation collected in these parts or any suitable fluid therein will cushion the valve against shock or jar in closing down onto its seat.

If it is desired to hold the valve 8 open for any purpose or when no back pressure is to be maintained, the screw 29 aifords a convenient means for causing the lever 17 to exert the required lifting power.

That I claim as my invention is- 1. A relief or back-pressure valve comprising a lower casing, an upper casing, an annular valve-seat web clamped between said casings to form fluid-tight joints therewith and provided with radial arms and a centrallysupported vertically-depending dash-pot con nected with said arms, a vertically-movable valve having a depending stem arranged to slide in said dash-pot, a valve-spring, and a compensating lever intermediate said spring and valve.

2. A relief or back-pressure valve comprising a lower casing, an upper casing, an annular valve-seat Web clamped between said casings to form fluid-tight joints therewith and provided with radial arms and a central vertically-depending dash-pot supported by said arms, and a vertically-movable valve having a depending hollow stem arranged to slide in said dash-pot for the purpose of guiding the valve onto its seat, the said hollow valve-stem being open at the top and having its closed lower end provided with a vertical passage in communication with the dash-pot, whereby fluid may be collected in the said hollow valve-stem and in the communicating space between the lower end of the stem and the bottom of the dash-pot to provide a cushion against shock or jar in the closing down of the valve onto its seat.

3. A relief or back-pressure valve comprising a lower casing, an upper casing, an interposed annular valve-seat web provided with radial arms and a central vertically-depending dash-pot supported by said arms, a Vertically-movable valve having a central depending hollow stem open at the top and fitted to slide freely in said dash-pot, a lever fulcrumed Within the valve-casing above the .valve, a post interposed between said lever and the bottom of the hollow valve-stem, and a spring arranged to bear downward on said lever and post to resist pressure against the under side of the valve.

4. A relief or back-pressure valve comprising a lower casing, an upper casing, an annular valve-seat web interposed between said casings and provided with radial arms and a central vertically-depending dash-pot sup ported by said arms, a vertically-movable valve having a central depending hollow stem open at the top and fitted to slide freely in said dash-pot, a lever fulcrumed at one end within the valve-casing, a post interposed between the other end of said lever and the bottom of the hollow valve-stem, a spring having one end bearing against said lever, and an adjusting-screw bearing against the other end of said spring to give different degrees of compression to the spring for resisting any predetermined pressure on the under side of the valve.

5. A relief or back-pressure valve comprising a lower casing, an upper casing, an annular valve-seat web clamped between said casin gs and provided with radial arms and a central vertically-depending dash-pot supported by said arms, a vertically-movable valve hav= ing a central depending stem fitted to slide freely in said dash-pot, a yoke-shaped lever fulcrumed at one end within the valve-casing and having its other end extended above the valve, a diagonally-arranged spring having one end bearing against said lever, and an adjusting-screw bearing against the other end of said spring, the relative arrangement of said lever and spring being such as to compensate for varying degrees of compression in the spring through the opening and clos= ing movements of the valve.

6. A relief or back-pressure valve comprising a lower casing, an upper casing, an annu lar valve-seat web provided with radial arms and a central vertically-depending dash-pot, a vertically-movable valve having a central stem fitted to slide freely in said dash-pot, a yoke-shaped lever fulcrumed within the valve-casing and having one end connected with the valve and its other end provided with a downward extension, an adjustingscrew inserted through the valve-casing and capable of adjustment to bear against said lever extension for causing the lever to lift the valve and hold it open, a diagonally-arranged spring having one end resting against said lever, and an adj usting-screw having a bearing against the other end of said spring.

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses.

ARTHUR W. CASH.

Witnesses:

JOHN A. MILLER, HORACE O. GRICE.

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