US3476141A

US3476141A - Fluid flow fuse

Info

Publication number: US3476141A
Authority: US
Inventors: Alfred Tillman
Original assignee: MAROTTA VALVE CORP
Current assignee: MAROTTA VALVE CORP
Priority date: 1967-01-13
Filing date: 1967-01-13
Publication date: 1969-11-04
Anticipated expiration: 1986-11-04

Description

Nov. 4, 1969 A. T|LLMAN 3,476,141

FLUID FLOW FUSE Filed Jan. 13, 1967 481] i INVENTOR ,o BY W r www. ATTORNEYS.

United States Patent C 3,476,141 FLUID FLW FUSE p Y Alfred Tillman, Mount Tabor, NJ., assigner to Marotta Valve Corporation, Boonton, NJ., a corporation of New .Ierse Filgd Jan. 13, 1967, Ser. No. 609,147

Int. Cl. F161( 31/36 U.S. Cl. 137-498 12 Claims ABSTRACT F THE DISCLOSURE to the uid pressure ahead of the restriction and connected with the valve element for closing the valve element when the pressure drop across the restriction exceeds a given value. This pressure drop is a function of the iiow rate. A sleeve on the outside of the housing can be rotated to change the cross section of the restriction and thus adjust the fuse to operate at different ilow rates.

Brief description of the invention The principal object of this invention is to provide an improved iiuid ow fuse for shutting oif further flow through a fluid line if the rate of flow becomes excessive, as in the case of a bursted hose or other accident. The invention provides an in-line fuse which is not substantially larger in diameter than conventional fittings for the size of pipe with which the fuse is used.

An important feature of the invention is its adjustability to operate at different flow rates, and the adjustment of the tlow rate from outside the housing. A sleeve surrounding the inner part of the housing of the fuse is movable to change the flow rate. In the preferred construction, the sleeve is threaded over an inner portion of the housing so that it moves axially when rotated, and this axial movement changes the restriction in the ilow passage through the housing so that the pressure drop is increased or decreased, depending upon the direction of adjustment, at a given flow rate, and the valve element closes at a different ow rate. The actual force for closing the valve element can remain constant and this greata ly simplifies the construction of the fuse.

4Other objects, features and advantages of the invention will appear or be pointed out as the description proceeds.

Brief description of the drawing Detailed description of the invention The fluid ow fuse includes a housing having an inlet fitting 12 at one end and an outlet fitting 14 at the other end. Both of these ttings are threaded to receive piping or other fittings of the uid flow line in which the Mice fuse `is used. In the preferred construction the

fittings

12 and 14 are part of the inner portion of the housing l0, and preferably of one-piece construction with the inner portion of the housing.

The housing 10 has an outer portion comprising a sleeve 16 which extends along most of the axial length of the fuse. This sleeve 16 has threads 18 which connect the sleeve with the inner portion of the housing, as shown in FIGURE 4. Rotation of the sleeve 16 causes it to move along its threaded connection with the inner portion of the housing and changes the axial position of the sleeve 16 with respect to the remainder of the fuse.

There is a plastic insert 29, in an opening through the sleeve 16, in contact with the threads on the inner portion of the housing. This insert 20 is pressed against the threads by a screw plug 22, threaded into the sleeve opening, to maintain a substantial friction between the insert 20 and the threads on the inner portion of the housing. A circumferential knurled area 26 provides a convenient grip for rotating the sleeve 1-6 with respect to the inner portion of the housing; and the friction of the insert 20 serves to hold the sleeve in any adjusted position.

Legends 3l) (FIGURE l) on the outside of the sleeve 16 indicate the direction in which the sleeve must be rotated in order to increase or decrease the iiow rate at which the fuse operates to shut olf further ilow. Axial movement of the sleeve 16 toward the left is limited by a snap ring 34 which tits into a groove 36 in the outlet fitting 14. Limitation of the movement of the sleeve 16 in the other direction will be explained in connection with the adjustment of the flow passage through the fuse housing.

FIGURE 4 shows the flow passage through the housing, and this passage includes an axial portion 40 of substantial diameter within the inlet fitting 12. At the inner end of this axial portion 4t) there are a plurality of angularly spaced radial openings 42 which extend substantially normal to the axis of the iiow fuse and which open through the wall of the inner portion of the housing into a circumferential recess 44. This recess 44 is covered by the outer sleeve 16 and the clearance between the bottom of the recess -44 and the inner surface of the sleeve 16 constitutes a part of the iiuid flow passage through the housing.

At one end of the recess 44 there is a shoulder 46 at which the diameter of the inner portion of the housing increases to substantially the inside diameter of the outer sleeve 16, and at a short distance beyond this shoulder 46 there is a seal, preferably an O-ring 48, located in a groove in the inner portion of the housing for preventing escape'of fluid from the circumferential recess 44 to the outside of the housing.

At the other end of the circumferential recess 44, there is a circumferential ridge 52 formed on the inner portion Vof the housing, and the left-hand side of the ridge 52 provides an annular face 54 which forms one side of another portion of the flow passage through the housing. The outer sleeve 16 has a circumferential groove 56 in its inner surface for providing a clearance for fluid ilow around the periphery of the ridge 52, and this groove 56 is of sufficient axial extent so that it provides clearance for fluid ow past the periphery of the ridge 52 for all adjusted positions of the outer sleeve 16.

The left-hand side of the groove 56 provides an annular face 64 which confronts the face 54 along at least a part of the radial extent of the faces 54 and 64. The clearance between these faces S4 and 64 changes progressively as the outer sleeve 16 is rotated to .screw it one way or the other along the inner portion of the housing. For example, as the sleeve 16 moves toward the right in FIGURE 4, the face 64 moves closer to the face 54 and the cross section of the clearance between the faces 54 and 64 decreases.

Conversely, movement of the sleeve 16 toward the left increases the cross section of the clearance between the faces S4 and 64. This clearance is an adjustable restriction in the flow passage through the fuse housing 1G, and by adjusting the cross section of this restriction, the pressure drop of the uid flowing through the housing of the fuse can be increased or decreased.

There are other radial openings 66 at angularly spaced locations and extending through the wall of the inner portion of the housing from the region of the restriction faces 54 and 64 to a chamber 68 which, with the radial openings 66, form another part of the tluid llow passage through the housing.

The fluid ow passage also includes an axial portion 70 in the outlet fitting 44; and this axial portion 70 communicates with the chamber 68 through a port 72 which has a valve seat 74 at its inner end. A valve element 76, in axial alignment with the port 72 and the

axial portions

40 and 70 of the flow passage, is movable toward and from the seat 74 to command the passage of fluid through the port 72.

The valve element 76 has a cylindrical portion which slides in a guide bearing 80 formed in the housing, and the valve element 76 is connected with a movable wall or piston 82 which reciprocates in a cylindrical chamber 84. The valve element 76 is urged into open position by a spring 86 compressed between the piston 82 and a shoulder 88 formed by one end of the cylindrical chamber 84. A snap ring 90 fits into a groove near one end of the cylindrical chamber 84 and limits movement of the piston 82 and the valve element 76 toward the right in FIGURE 4.

The cylindrical chamber 84 communicates with the axial portion 40 of the ow passage. Thus the piston 82 is exposed to pressure of the fluid in the housing upstream of the restriction in the flow passage between the annular faces 54 and 64.

Whenever the pressure drop between the axial portion 40 of the ow passage and the portion of the How passage downstream from the restriction is enough to overcome the force of the spring 86, the valve element 76 moves into closed position. The actual force required to compress the spring 86 and to move the valve element 76 into closed position is always the same since there is no provision for adjusting the force of the spring 86. However, the actual flow of fluid which will produce a force suficient to compress the spring 86 depends upon the pressure drop in the ow passage, and more particularly in the portion of the llow passage at the restriction between the faces 54 and 64. This spring-compressing pressure can be obtained at widely diferent rates of tlow, depending upon changes in the cross section of the clearance between the faces 54 and 64. Thus the fuse can be adjusted to close at different flow rates by merely rotating the outer sleeve 16 to screw it one way or another along the inner portion of the housing. The seal 48 at one end of the sleeve 16 and a corresponding seal 48 near the other end of the sleeve, prevent escape of fluid from the housing without interfering with the rotation of the sleeve i6.

What is claimed is:

1. A iluid flow fuse including a housing having a llow passage therethrough including a valve chamber, said passage having a port at one end of the valve chamber with a valve seat around the periphery thereof, a valve element in the valve chamber movable toward and from the port to control the tlow of fluid through the housing, resilient means urging the valve element toward its open position, a portion of the valve chamber upstream from the seat having a movable wall which is exposed on its upstream side to an inlet pressure in the housing the flow passage having a portion of restricted cross section outside of the valve chamber and by-passing the movable wall and leading from a location upstream of the movable wall to a location in the valve chamber beyond the range of movement of the movable wall and downstream thereof,

and an operative connection between the movable wall and the valve element, for moving the valve element into closed position, the restriction of the flow passage being correlated with the movable wall and said resilient means to move the valve element into closed position when the liow rate through the restriction exceeds a given value.

2. The fluid llow fuse described in claim 1 characterized by a portion of said chamber being cylindrical, and the movable wall closing one end of said cylindrical p0rtion and said operative connection extending axially of said cylindrical portion, the valve element, when in open position, being spaced from the valve seat by a distance that produces a further restriction of the tiow passage and a second significant pressure drop for causing the valve to `move into closed position when the pressure drop exceed said given value.

3. The fluid flow fuse described in claim 2, characterized by the cylindrical portion having a shoulder at one end, and the movable wall being a piston in axial alignment with the valve seat, the piston and its operative connection with the valve element both being of integral construction with the valve element, the resilient means being a helical spring located in the cylindrical portion and compressed between the piston and the shoulder at one end of the cylindrical portion, the valve element extending into the lluid passage through the seat when the valve element is in open position, and restricting the fluid flow through the valve seat port to throttle further the llow of uid from the restricted by-pass.

4. The luid tlow fuse described in claim 3 characterized by another shoulder at the other end of the cylindrical portion comprising a removable stop that locks into the cylindrical portion on the side of the piston opposite the spring.

5. A lluid fuse including a housing having a flow passage therethrough, said passage having a port with a valve seat around the periphery thereof, a valve element movable toward and `from the port to control the ow of fluid through the housing, resilient means urging the valve element toward its open position, the housing having a portion of its ow passage, including at least a portion of the flow passage upstream from the valve seat, restricted so that a pressure drop occurs therein proportional to the rate of ow of uid through the housing, a portion of the flow passage upstream from the restriction comprising a chamber having a movable wall which is exposed to the pressure in the housing before said pressure drop, and an operative connection between the movable wall and the valve element, the operative connection and the valve element being positioned for moving the valve element into closed position when the pressure drop across the restriction exceeds a given value, and characterized by adjustable means operative from outside of the housing for changing the minimum cross section of the restricted portion of the flow passage upstream from the valve seat to change the pressure drop and thereby change the flow rate at which the valve element closes against the valve seat to stop the ow through the ow passage.

6. rlhe fluid ow fuse described in claim 5 characterized by the adjustable means including an outer sleeve portion of the housing rotatable on and surrounding at least a part of the length of an inner portion of the housing.

7. The iluid flow fuse described in claim 6 characterized by the restricted portion of the flow passage being a clearance between an inside surface of the sleeve portion and an outside surface of the inner portion of the housing, and the sleeve portion being threaded on the inner portion to obtain axial movement of the sleeve portion on the inner portion in response to rotation of the sleeve portion.

`8. The uid tlow fuse described in claim 6 characterized by the restricted portion of the ow passage extending between confronting annular shoulders on the sleeve and on the inner portion of the housing, said shoulders being movable toward and from one another to change the cross section of the clearance between them.

9. The fluid llow fuse described in claim 1 characterized by the housing including an inner portion and an outer portion movable with respect to the inner portion, inlet and outlet ports at opposite ends of the inner portion of the housing and in line with one another, making the fuse an in1ine, the restricted portion of the flow passage being adjustable in cross section in response to movement of the outer portion of the housing on the inner portion.

10. The fluid flow fuse described in claim 9 characterized by the inner portion of the valve housing being of circular cross section, radial openings through the wall of the inner portion at axially spaced locations on the upsteam side of the valve seat, the outer portion of the housing being a sleeve that surrounds the inner portion and that has a clearance from the outer surface of the inner portion at the radial openings and along the axial distance between radial openings, said clearance constituting the restricted portion of the flow passage through the housing, and seals at opposite ends of said clearance.

11. The fluid flow 4fuse described in claim 9 characterized by a circumferential ridge on one, and a circumferential groove in the other, of confronting faces of the outer and inner portions of the housing and providing annular faces that form opposite sides of part of the length of the ow passage, the outer portion of the housing being threaded on the inner portion and movable axially thereon in response to relative rotation of the inner and outer portions with respect to one another to move the annular surfaces together or apart to change the restriction in the ow passage and means for controlling the friction of the outer portion on the inner portion of the housing.

12. The fluid ilow fuse described in claim 1 characterized by the housing having outer and inner concentric portions with confronting faces having a clearance between them for a portion of their axial lengths, said clearance constituting a part of the length of the ilow passage through the housing, a circumferential ridge on one, and a circumferential groove in the other of the confronting faces of the outer and inner portions of the housing and providing annular faces that -form opposite sides of the restricted part of the length of the flow passage, the outer portion of the housing being threaded on the inner portion and movable axially thereon in response to relative relation of the inner and outer portions with respect to one another to move the annular surfaces together or apart to change the restriction in the ow passage, the axial width of the groove Ibeing greater than the axial width of the ridge to provide clearance for the ow of iluid along the side of the ridge opposite said annular surfaces.

References Cited UNITED STATES PATENTS 2,710,626 6/1955 Burdick et al. 137-498 2,821,209 l/ 1958 Waterman 137-498 2,865,397 12/1958 Chenault 13750l XR 3,357,448 12/1967 Martin 137-501 M. CARY NELSON, Primary Examiner R. I. MILLER, Assistant Examiner