US3246660A

US3246660A - Self-propelled nozzle

Info

Publication number: US3246660A
Application number: US327345A
Authority: US
Inventors: Hammelmann Paul
Original assignee: Individual
Current assignee: Individual
Priority date: 1962-12-03
Filing date: 1963-12-02
Publication date: 1966-04-19
Anticipated expiration: 1983-04-19
Also published as: DE1195102B; GB989676A; FR1376237A

Description

April 19, 1966 P. HAMMELMANN 3,246,650

SELF-'PROPELLED NOZZLE Filed Dec. 2, 1965 Jwenfar:

PA UL [M "NH MANN United States Patent M ,570 29 Claims. (Cl. 134-167) The present invention relates to nozzles in general, and more particularly to an adjustable self-propelling nozzle which is especially suited for cleaning of tunnels, canals and similar tubular structures. Still more particularly, the invention relates to an adjustable nozzle adapted to discharge one or more jets of compressed fluid at a rate which is proportional with the pressure of fluid.

It is an important object of the present invention to provide a nozzle which is constructed and assembled in such a way that the rate of fluid discharge is adjusted in a fully automatic way, that the conduit which delivers pressure fluid thereto cannot be subjected to excessive stresses, and that the fluid may be discharged in several directions.

Another object of the invention is to provide a nozzle of the just outlined characteristics wherein the rate of fluid discharge may be varied with utmost precision and in exact proportion with changes in fluid pressure, which may be readily taken apart and reassembled with little loss in time, which may be rapidly converted to discharge jets of compressed fluid in different directions, and which may be utilized in connection with many conventional pressure generating and fluid conveying devices.

A further object of the invention is to provide an adjustable nozzle for discharging jets of water or another cleaning fluid which may be used for discharging very small or very large quantities of fluid per unit of time, and which is capable of long-lasting use without necessitating any adjustments on the part of the operator.

With the above objects in view, one feature of my invention resides in the provision of an adjustable selfpropelling nozzle, particularly for discharging jets of compressed fluid media into a tube or the like, which comprises a fluid conveying member having a passage arranged to be connected with a pump or another suitable source of compressed fluid, and a tubular member surrounding the fluid conveying member and having an internal surface which is closely adjacent to and in sealing engagement with an external surface of the fluid conveying member. One of these surfaces is provided with at least one fluid discharging channel or orifice which communicates with the passage in the fluid conveying member and one of these members is movable by fluid pressure with reference to the other member between a plurality of positions to expose different portions of the channel. The channel is conflgurated in such a way that the rate at which it discharges a jet of compressed fluid varies in response to movement of the one member with reference to the other member. If the pressure of fluid rises, the fluid acts against suitably formed surfaces on the two members or on parts connected therewith in a sense to increase the rate of fluid outflow through the channel when the pressure rises. It is preferred to provide resilient means for biasing the members in a direction counter to the direction of fluid pressure so that the rate of fluid outflow decreases automatically when the pressure of fluid decreases. The channel discharges the fluid in such a Way that the jet produces a thrust which propels the nozzle through a tubular body.

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved nozzle itself, however,

3,246,660 Patented Apr. 19, 1966 both as to its construction and its mode of operation, together with additional features and advantages thereof, will be best understood from the following detailed description of a specific embodiment with reference to the accompanying drawings, in which:

FIG. 1 is an axial section through a self-propelling nozzle which embodies the invention;

FIG. 2 is a transverse section as seen in the direction of arrows from the line HII of FIG. 1; and

FIG 3 is an end view of a ring which is utilized in the nozzle of FIG. 1.

Referring to PEG. 1, there is shown an adjustable self propelling nozzle which comprises a fluid conveying inner tubular member 1 here shown as a cylinder which is formed with a central passage In one end of which is provided with internal threads 2 to receive the nipple of a hose or a similar conduit serving to connect the cylinder with a source of compressed fluid, e.g., a water pump or the like. The peripheral surface of the cylinder 1 is provided with a series of axially parallel fluid discharging channels or orifices 7 of triangular cross section, and each of these channels comprises a lower portion whose cross-sectional area diminishes toward the lower axial end of the cylinder 1 and an upper portion whose crosssectional area diminishes in a direction toward the upper axial end of the cylinder. Each of these channels communicates with a radial bore 6 which leads to the passage 1a. There is an annular recess lb which connects th outer ends of the bores 6 with each other to insure that the pressure in each of the channels 7 is the same.

The upper end portion of the cylinder 1 is provided with internal threads, as at 8, to mesh with external threads at the lower end of a cylindrical sleeve 9 which serves to guide a resilient element 10 here shown as a package of dished springs acting between an external annular stop collar 11 of the sleeve and a second stop here shown as a multi-section ring 12 which is recessed in an annular groove 40 provided in the internal surface of a cylindrical outer tubular member or shell 4-. The lower end portion of this tubular member 4 sealingly surrounds the peripheral surface of the cylinder 1 and normally conceals the channels 7 and. the discharge end thereof when the resilient element 10 is permitted to expand, i.e., when the passage 1a in the cylinder 1 is disconnected from a pump or another source of compressed fluid so that the tubular member 4 moves to its starting position. The upper end portion 4a of the tubular member 4 surrounds and is slidable axially along the upper end portion of the sleeve 9 so that the tubular member remains in a position of coaxial alignment with but is movable with reference to the cylinder 1 or vice versa. The uppermost part of the end portion 4a is provided with internal threads 3 mating with the internal threads of a cap 5 which is formed with a single fluid discharging orifice 13. The diameter of the threaded portion on the cap 5 is the same as the diameter of the threaded portion 2 so that the cap may be screwed into the lower end of the cylinder 1 when the nozzle is not in use or, alternatively, a second cap may be screwed into the cylinder to prevent entry of large impurities.

The resilient element 10 tends to move the cylinder 1 upwardly, as viewed in FIG. 1, so that the channels 7 are normally concealed within the internal surface of the outer tubular member 4. However, when the threaded portion 2 is connected with a hose which leads to a pump or the like, the fluid fills the interior of the sleeve 9 and escapes through the orifice 13. This means that the fluid exerts a pressure which tends to move the tubular member 4 upwardly whereby the lower end face 4b of the tubular member travels along the channels 7 and comes to rest in a position which corresponds to momentary pressure of the fluid so that the rate at which the discharge end or the lower portions of the channels 7 discharge jets of compressed fluid rearwardly depends on the axial position of the members 1 and 4 with reference to each other. The fluid acts against the bias of the resilient element 10 which tends to retract the cylinder 1 into the interior of the tubular member 4.

It is possible to replace the cap by a cap which is without an orifice. In such constructions, the fluid filling the interior of the sleeve 9 will act against the inner end of the cap and will cause axial displacement of the tubular member 4 with reference to the cylinder 1 or vice versa. Also, the fluid acts against the upper end face 9a of the sleeve 9 and against the annular inner end face 5a of the cap 5 to bring about axial displacement of the member 4 in response to changes in fluid pressure.

FIG. 2 shows that the channels 7 are of triangular cross section and that they diverge in a direction toward the internal surface of the tubular member 4. The upper portions of the channels 7 (above the level of the recess 1b, as viewed in FIG. 1) are not active in controlling the rate of fluid discharge and are provided merely for convenience of machining when the channels are formed.

FIG. 3 shows that the ring 12 comprises three

arcuate sections

12a, 12b, 120 which are inserted into the annular groove 40 of the outer tubular member 4 prior to connecting the cylinder 1 with the sleeve 9. It goes without saying that the resilient element It) may comprise one or more helical springs or the like as long as it resists the pressure of compressed fluid which tends to move the members 1 and 4 with reference to each other in a sense to expose the channels 7 and to thus increase the rate of fluid outflow in response to movement of the cylinder 1 downwardly, as viewed in FIG. 1. This will be readily understood since the cross-sectional area of the lower portion of each channel 7 increases in a direction toward the cap 5, i.e., toward the upper end portion 4a of the outer tubular member 4.

A retaining element here shown as a screw 14 extends radially inwardly through a tapped bore provided in the lower end portion of the tubular member 4 and its tip extends into one of the channels 7 to prevent angular displacement of the tubular member 4 with reference to the cylinder 1 or vice versa. Some angular displacement may take place if the channels 7 are of helical outline; all that counts is to form the channels in such a way that their cross-sectional areas vary in the longitudinal direction of the cylinder 1. The feature that the tip of the retaining screw 14 extends into one of the channels 7 is of importance because the peripheral surface of the cylinder 1 remains unscratched when the cylinder reciprocates with reference to the tubular member 4 so that the cooperating surfaces of the cylinder 1 and tubular member 4 form a tight seal to prevent uncontrolled escape of compressed fluid, i.e., the fluid can escape rearwardly through the lower ends of the channels 7 and forwardly through the orifice 13. The cross-sectional area of the orifice 13 cannot be varied; thus, if the operator desires to discharge a stronger or weaker stream of fluid in the axial direction of the nozzle, it is necessary to replace the cap 5 by a cap having a differently dimensioned orifice.

The extent of axial movement of the members 1 and 4 with reference to each other depends on compression of the resilient element and on the momentary pressure of a fluid medium which is admitted into the passage 1a. The movement of the members 1 and 4 with reference to each other is terminated when the bias of the element It) balances the pressure of compressed fluid so that the rate of fluid discharge through the channels 7 depends on the pressure prevailing in the hose which delivers fluid into the passage 1a. This insures that the nozzle will discharge more fluid if the pressure in the hose which delivers fluid into the passage la rises whereby the hose is protected against excessive pressures such as could cause bursting and flooding in the event that the pressure fluid is water which is used for cleaning of tunnels, underground canals and similar tubular structures.

Owing to the fact that the cross-sectional areas of the channels 7 diminish in a direction toward the lower end of the cylinder 1, as viewed in FIG. 1, these channels produce a very satisfactory Venturi effect.

The resilient element 10 compensates for wear on the cooperating parts of the nozzle. Thus, if the cross-sectional areas of the channels increase in response to wear after extended periods of use, the springs will expand because the pressure of fluid in the tube 9 and cap 5 will drop. Such adjustments to compensate for wear will take place in a fully automatic way. Of course, the nozzle will be adjusted automatically in response to any fluctuations in pressure of fluid which enters the sleeve 9 to avoid damage to the hose and to the pump or another source of compressed fluid.

The bias of the resilient element 10 may be adjusted in such a way that it corresponds to a maximum pressure of conveyed fluid. If the characteristic curve of the resilient element 10 is or resembles a straight line, automatic adjustments of the nozzle will be very satisfactory because the bias of the spring will increase proportionally with rising pressure of fluid. For example, if the pump is adjusted in a sense to deliver the fluid at a given maximum pressure, the bias of the resilient element may be selected in such a way that, at such maximum pressure, the channels 7 will deliver jets of compressed fluid at a required rate.

When the nozzle of my invention is put to actual use, the operator attaches the cylinder 1 with the discharge end of a hose H and starts the pump to discharge jets of compressed fluid at a rate depending on the extent to which the internal surface of the tubular member 4 exposes the channels 7. If the operator does not wish to discharge a jet of compressed fluid forwardly, the cap 5 is replaced by a different cap which is without an orifice. The self-propelling effect then depends exclusively on the pressure of fluid.

The nozzle of the present invention is especially suited for cleaning of tubes or the like and acts as a self-propelling body because the jets of fluid discharged through the channels 7 will flow rearwardly and will produce a forward thrust which advances the nozzle through a tube.

Such self-propelling nozzles must be constructed and assembled with a view to reduce friction when the nozzle travels in a tube so that the nozzle may be accelerated and reaches a high speed. Also, the configuration of the channels or orifices through which the jets of compressed fluid escape must be selected with a view to insure that the nozzle will operate with optimum efficiency and that the outflow of fluid is throttled at the time the fluid pressure is low to insure that the pressure of fluid flowing through the channels and orifices is suflicient for a cleaning and self-propelling action.

In conventional cleaning devices for tubes or the like, it was necessary to use a separate self-propelling nozzle for each fluid pressure or for each type of fluid generating means. Also, such conventional nozzles cannot compensate for wear when jets of highly compressed fluid are caused to flow through one or more throttling orifices. Thus, a new nozzle of conventional design must be manufactured with orifices whose cross-sectional area is less than is necessary for optimum operation because the cross-sectional areas of the orifices will increase in response to wear caused by the outflowing fluid. In other words, it takes some time before a conventional nozzle will operate with optimum efliciency.

Additional losses will be caused by the pressure relief valve of the pump which delivers compressed fluid to a conventional nozzle Thus, at least some energy will be lost when a new nozzle with orifices of less than optimum cross-sectional area is connected with the pressure side of a pump because the relief valve Will be compelled to throttle the outflow of fluid until the cross-sectional areas of the orifices increase in response to wear. In the nozzle of my invention, the cross-sectional areas of the channels 7 (which actually constitute a series of rearwardly directed orifices) are automatically selected in such a way that the rate of fluid discharge corresponds to the rate at which the pump delivers fluid to the passage lla. Thus, no energy will be lost because the relief valve in the conduit connecting the pump with the cylinder 1 remains inactive.

It should be borne in mind that the self-propelling nozzle of my invention is normally connected with a hose which is convoluted on a reel and which is paid out by the reel when the nozzle travels in an elongated tube. The resistance which the hose offers to the flow of compressed fluid varies continuously as the nozzle moves through a tube and the nozzle will automatically compensate for such variations in resistance. If the nozzle were provided with channels or orifices of unchanging effective cross-sectional area, it could happen that the fluid would expand and destroy the hose in response to very high pressure such as develops when the rate at which the pump delivers fluid exceeds the rate at which the nozzle can discharge such fluid. The danger of destroying the hose is particularly great when the hose is very long. Thus, and when a stream of highly compressed fluid which has travelled through a long hose reaches a nozzle which cannot discharge the fluid at the same rate at which the fluid is fed into the hose, the pressure in the hose rises instantaneously and may cause immediate destruction. This cannot happen if a nozzle is constructed in accordance with the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic and specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. An adjustable nozzle, particularly for discharging jets of compressed fluid media into a tube or the like, comprising a fluid conveying member having a passage arranged to be connected with a source of compressed fluid; and a tubular member surrounding said fluid conveying member, each of said members having a surface closely adjacent to the other surface and one of said surfaces being provided with a channel communicating with said passage and having a discharge end, one of said members being movable with reference to the other member between a starting position in which the discharge end of said channel is sealed and a plurality of additional positions to expose different portions of said discharge end and said channel being configurated in such a way that the rate at which a jet of compressed fluid issues from said discharge end varies in dependency on the extent of the movement of said one member with reference to the other member from said starting position.

2. An adjustable nozzle, particularly for discharging jets of compressed fluid media into a tube or the like, comprising an inner tubular member having a passage arranged to be connected with a source of compressed fluid, said tubular member having a peripheral surface provided with at least one fluid discharging channel whose crosssectional area varies in the longitudinal direction of said tubular member and said channel being in communication with said passage and having a discharge end; and an outer tubular member having an internal surface sealingly surrounding said peripheral surface, one of said members being movable with reference to the other thereof between a starting position in which said discharge end of said channel is sealed and a plurality of additional 6 positions in which different portions of said discharge end remain exposed whereby the rate at which a jet of compressed fluid issues from said discharge end varies in dependency on the extent of the movement of said one member with reference to the other member from said starting position.

3. An adjustable self-propelling nozzle, particularly for discharging jets of compressed fluid media into a tube or the like, comprising an inner cylinder having a central passage arranged to be connected with a source of c0mpressed fluid, at least one radially extending bore communicating with said passage, and a peripheral surface provided with a channel which communicates with said bore and Whose cross-sectional area varies in the axial direction of said inner cylinder said channel having a discharge end; and an outer cylinder having an internal surface sealingly surrounding said peripheral surface and movable axially with reference to said inner cylinder between a starting position in which said discharge end of said channel is sealed and a plurality of additional positions in which different portions of said discharge end remain exposed whereby the rate at which a jet of compressed fluid issues rearwardly from said discharge end varies in dependency on the extent of the movement of said outer cylinder with reference to said inner cylinder from said starting position and the jet produces a thrust which propels the nozzle in the opposite direction.

4. An adjustable nozzle, particularly for discharging jets of compressed fluid media into a tube or the like, comprising an inner tubular member having a passage arranged to be connected with a source of compressed fluid, said tubular member having a peripheral surface provided with at least one fluid discharging channel whose cross-sectional area increases in one longitudinal direction of said tubular member and said channel being in communication with said passage and having a discharge end; and an outer tubular member having an internal surface sealingly surrounding said peripheral surface, one of said members being movable with reference to the other thereof between a starting position in which said discharge end of said channel is sealed and a plurality of additional positions, said outer tubular member having an end face which moves along said discharge end in dependency on the extent of the movement of said one member with reference to the other member whereby the rate at which a jet of compressed fluid issues from said discharge end varies in response to movement of said one member with reference to the other member.

5. A nozzle as set forth in claim 4, wherein said one member is movable between two end positions and wherein the rate at which a jet of fluid issues from said discharge end increases when said one member moves in a direction from one of said end positions toward the other end position.

6. An adjustable nozzle, particularly for discharging jets of compressed fluid media into a tube or the like, comprising an inner tubular member having a passage arranged to be connected with a source of compressed fluid, said tubular member having a peripheral surface provided with at least one fluid discharge channel of triangular cross section whose cross-sectional area varies in the longitudinal direction of said tubular member and said channel being in communication with said passage and having a discharge end; and an outer tubular member having an internal surface sealingly surrounding said peripheral surface, one of said members being movable with reference to the other thereof between a starting position in which said discharge end of said channel is sealed and a plurality of additional positions in which different portions of said discharge end remain exposed whereby the rate at which a jet of compressed fluid issues from said discharge end varies in dependency to the extent of the movement of said one member with reference to the other member from said starting position.

7. An adjustable nozzle, particularly for discharging jets of compressed fluid media into a tube or the like, comprising an inner tubular member having a passage arranged to be connected with a source of compressed fluid, said tubular member having a peripheral surface provided with at least one fluid discharging channel Whose cross-sectional area varies in the longitudinal direction of said tubular member and said channel being in communication with said passage and having a discharge end; and an outer tubular member having an internal surface sealingly surrounding said peripheral surface, one of said members being movable by fluid pressure with reference to the other thereof in one longitudinal direction and between a starting position in which said discharge end of said channel is sealed and a plurality of additional positions in which different portions of said discharge end remain exposed whereby the rate at which a jet of compressed fluid issues from said discharge end varies in dependency on the extent of the movement of said one member with reference to the other member; and resilient means for biasing said one member from said starting position in the other longitudinal direction thereof to resist the pressure of fluid.

8. A nozzle as set forth in claim 7, wherein said resilient means comprises a package of dished springs.

9. An adjustable self-propelling nozzle, particularly for discharging jets of compressed fluid media into a tube or the like, comprising an inner tubular member having a central passage arranged to be connected with a source of compressed fluid at one end thereof, said tubular member further having a peripheral surface provided with at least one channel whose cross-sectional area varies in the longitudinal direction of said member and which communicates with said passage; a sleeve coaxially secured to said tubular member and extending beyond the other end of said passage, said sleeve having an end portion distant from said tubular member and an external collar located between said tubular member and said end portion; an outer tubular member having an internal surface sealingly surrounding said peripheral surface and an end portion slida-bly surrounding the end portion of said sleeve, one of said tubular members being movable axially with reference to the other thereof in response to pressure of fluid admitted to said passage whereby said internal surface exposes different portions of said channel to vary the rate at which said channel discharges a jet of compressed fluid; an annular stop provided in said outer tubular member intermediate said collar and said inner tubular member; and a resilient element disposed between said collar and said stop to bias said one tubular member in a direction counter to the direction of movement in response to fluid pressure.

10. A nozzle as set forth in claim 9, wherein said stop is a ring a portion of which is recessed into the internal surface of said second tubular member.

11. A nozzle as set forth in claim 16, wherein said ring comprises a plurality of arcuate sections.

12. An adjustable nozzle, particularly for discharging jets of compressed fluid media into a tube or the like, comprising an outer tubular member having an internal surface, a first end portion, and a second end portion; an inner tubular member having a peripheral surface slidably received in the first end portion of said outer tubular member, and said inner tubular member further having a passage arranged to be connected to a source of compressed fluid and at least one channel provided in said peripheral surface and communicating with said passage, the cross-sectional area of said channel varying in the longitudinal direction of said inner tubular member and one of said members being movable longitudinally with reference to the other thereof in response to the pressure of fluid which is admitted into said passage so that said inner tubular member moves outwardly and beyond the first end portion of said outer tubular member when the pressure of fluid increases whereby the internal surface of said outer tubular member exposes different portions of said channel to vary the rate at which said channel discharges a jet of compressed fluid; and a cap detachably received in the second end portion of said outer tubular member.

13. An adjustable nozzle as set forth in claim 12, wherein said cap is provided with a fluid discharging orifice which communicates with said passage and wherein the fluid acts against said cap to cause axial movement of said tubular members with reference to each other.

14. An adjustable nozzle as set forth in claim 12, further comprising a resilient element arranged to bias said inner tubular member in a direction to withdraw said channel into said outer tubular member.

15. An adjustable nozzle as set forth in claim 12, wherein said cap is provided with external threads and wherein the second end portion of said outer tubular member is provided with internal threads mating with the threads of said cap.

16. An adjustable nozzle as set forth in claim 15, wherein said inner tubular member has an end portion provided with internal threads and located at that end of said passage which is distant from said cap, said cap being receivable in the end portion of said inner tubular member.

17. An adjustable nozzle, particularly for discharging jets of compressed fluid media into a tube or the like, comprising an inner tubular member having a passage arranged to be connected with a source of compressed fluid, said tubular member having a peripheral surface provided with at least one fluid discharging channel whose crosssectional area varies in the longitudinal direction of said tubular member and said channel being in communication with said passage and having a discharge end, said tubular member and said channel being arranged to reverse the direction of flow of a portion of the fluid between said passage and said discharge end substantially by a sleeve member coaxial with said tubular member and connected therewith, said sleeve member to receive the remaining portion of said fluid; an outer tubular member having an internal surface sealingly surrounding said peripheral surface, one of said members being movable with reference to the other thereof between a starting position in which said discharge end of said channel is sealed and a plurality of additional positions in which different portions of said discharge end remain exposed whereby the rate at which a jet of compressed fluid issues from said discharge end varies in dependency on the extent of the movement of said one member from said starting position with reference to the other member; and retaining means secured to said outer tubular member and extending into said channel to guide said members during relative movement with reference to each other.

18. An adjustable nozzle as set forth in claim 17, wherein said retaining means comprises a radially extending screw threaded into said outer tubular member and having a tip projecting into said channel.

19. An adjustable nozzle as set forth in claim 17, wherein said channel is substantially parallel with the axis of said inner tubular member so that said retaining means prevents rotation of said members with reference to each other.

20. An adjustable self-propelling nozzle, particularly for discharging jets of compressed cleaning fluids into a tube or the like comprising an outer cylinder having a first end portion, a second end portion and a cylindrical internal surface in said first end portion thereof, said cylinder further having internal threads provided in said second end portion thereof and a ring-shaped internal groove provided between said end portions; an inner cylinder having a central passage arranged to be connected with a source of compressed fluid and a peripheral surface sealingly and slidably received in said internal surface, said inner cylinder further having a plurality of substantially axially parallel fluid discharging channels provided in said peripheral surface thereof and radial bores connecting said channels with said passage, the cross-sectional area of each of said channels varying in the axial direction of said inner cylinder and one of said cylinders being movable with reference to the other thereof to expose different portions of said channels in response to the pressure of a fluid admitted into said passage so that the rate at which said channels discharge jets of compressed fluid in a direction away from the second end portion of said outer cylinder varies in dependency on the axial position of said cylinders with reference to each other and the nozzle is propelled in a direction counter to the direction of fluid flow through said channels; a cylindrical sleeve coaxially secured to said inner cylinder and having a portion slidably extending into the second end portion of said outer cylinder, said sleeve having an annular collar disposed between said inner cylinder and the second end portion of said outer cylinder; a ring comprising a plurality of arcuate sections received in said groove; a resilient element disposed between said collar and said ring and arranged to bias said cylinder in a direction to withdraw said inner cylinder into said outer cylinder; a radial retaining screw passing through said outer cylinder and extending into one of said channels to prevent angular displacement of said cylinders with reference to each other; and a cap provided with external threads meshing with the threads of said second end portion, said cap having a fluid discharging orifice which receives compressed fluid from said passage via said sleeve and said cap having a portion which is acted upon by the fluid in said sleeve so that the cap moves away from the sleeve when the pressure of fluid increases.

References Cited by the Examiner UNITED STATES PATENTS 1,675,738 7/1928 Titcomb et al. 1,898,325 2/1933 Venn 239-453 2,263,197 11/1941 Tabb et a1 239-453 3,165,109 1/1965 Hammelmann 134167 FOREIGN PATENTS 246,784 10/ 1947 Switzerland.

CHARLES A. WILLMUTH, Primary Examiner.

ROBERT L. BLEUTGE, Assistant Examiner.