US3820560A

US3820560A - Reserve valve mechanism permitting refilling of scuba tank regardlessof valve setting

Info

Publication number: US3820560A
Application number: US00327719A
Authority: US
Inventors: K Leemann
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-01-29
Filing date: 1973-01-29
Publication date: 1974-06-28
Anticipated expiration: 1991-06-28

Abstract

A reserve mechanism for use with a self-contained breathing apparatus includes a valve which permits the breathing gas supply tank to be refilled regardless of the valve setting. The valve includes two cooperating members, an annular valve seat member and a piston member, which are spring biased toward a flow impeding position. Each member is movable in a direction opposite the other, so that the valve opens when the gas pressure in either direction exceeds the spring bias force. This permits gas from a compressor or other source to flow in the reverse direction through the valve and refill the tank even though the valve is not set to the manually opened, ''''reserve'''' position.

Description

United States Patent 1 Leemann June 28, 1974 RESERVEVALVE MECHANISM PERMITTING REFILLING OF SCUBA TANK REGARDLESS OF VALVE SETTING Inventor: Karl Leemann, Wehntalersh 142 8057, Zurich, Switzerland Filed: Jan. 29, 1973 Appl. No.: 327,719

US. Cl. l37/493.4, 137/495 Int. Cl. F16k 45/00, Fl6k 17/00 Field of Search 137/495, 508, 493, 493.4, 137/512.5, 523, 530, 543.15, 493.6, 493.9, 494, 63 R; 128/l45.7, 202, 145.6

References Cited UNITED STATES PATENTS 3,722,535 3/1973 Ruupp 137/493.4

Primary Examiner-Henry T. Klinksiek Assistant Examiner-Robert J. Miller Attorney, Agent, or Firm Flam & Flam 57] ABSTRACT A reserve mechanism for use with a self-contained breathing apparatus includes a valve which permits the breathing gas supply tank to be refilled regardless of the valve setting. The valve includes two cooperating members, an annular valve seat member and a piston member, which are spring biased toward a flow impeding position. Each member is movable in a direction opposite the other, so that the valve opens when the gas pressure in either direction exceeds the spring bias force. This permits gas from a compressor or other source to flow in the reverse direction through the valve and refill the tank even though the valve is not set to the manually opened, reserve" position.

8 Claims, 5 Drawing Figures PATENTEDJUN28 m4 SHEET 1 [IF 2 Q mm REFILLING OF SCUBA TANK REGARDLESS OF VALVE SETTING BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scuba reserve mechanism which permits refilling of the scuba tank regardless of the setting of the reservevalve.

2. Description of the Prior Art To allow safe return to the surface, the user of a selfcontained underwater breathing apparatus (scuba) must begin his ascent when there is yet a supply of breathable gases in his tank adequate for the ascent. For this purpose, known reserve valves are used which include a springbiased closure which actually shuts off the flow of breathable gas when the scuba tank pressure drops to avalue corresponding to the spring force. Thereupon the diver operates a manual override to retract the closure, and the flow of breathable gas is reestablished. However the diver now knows that the tank supply is not exhausted, and he begins his ascent.

A'problem arises when the tank is refilledjlf the reserve valve is left in the reserve position with the closure retracted, the tank can be refilled normally through the open valve. But if the reserve valve should be set with the closure biased to aflow impeding position, the tank cannot be refilled. Air from the compressor, flowing in a direction opposite that associated with scuba breathing, will not open the closure, and may force it more tightly shut. This situation may not be noticed until the next dive with that tank, when the diver quickly'learns that his tank is substantially empty.

This problem is particularly acute should the unfilled tank be used with-a properly filled tank in a tandem arrangement with a single reserve valve. When the valve is switched to reserve, the air remaining in the previously filled tank is partly distributed to the unfilled tank, causing the pressure of the available air suddenly to decrease.

The principal object of the present invention is to provide a reserve valve mechanism which will permit the associated scuba tank to be refilled regardless of the valve setting. The likelihood of a tank not being refilled is eliminated' SUMMARY OF THE INVENTION This objective is achieved by providing a reserve mechanism including a valve disposed in the flow path between a tank containing air or other breathable gas and other components of the breathing apparatus. The valve includes two cooperating members, a valve seat member and a piston member, which are spring biased into a closed or flow impeding position. When the tank pressure exceeds the spring bias force, air from the tank presses open one of the valve members and flows to the other breathing apparatus components. The valve may be opened manually to permit the unimpeded flow of reserve air from the tank to the user when the tank pressure drops below the preset level established by the spring bias force. To refill the tank, gas from a compressor or other high pressure source is connected to the tank via the valve. The pressure of gas from this source opens the other valve member, permitting the tank to be refilled even though the valve is not set to the open. reserve" position.

BRIEF DESCRIPTION OF THE DRAWINGS A detailed description of the invention will be made with reference to the accompanying drawings, wherein like numerals designate corresponding parts in the several figures, The drawings are to scale.

FIG. I is a pictorial view showing utilization of the inventive reserve valve meehanisn in conjunction with a self-contained underwater breathing apparatus.

FIG. 2 is a transverse sectional view of the inventive reserve valve mechanism as seen generally along the line 22 of FIG. I. The valve is shown in the reserve position permitting unimpeded flow of reserve air from the scuba tank.

FIG. 3 is a transverse sectional view, as seen generally along the line 3 3 of FIG. 2, and showing the cam shaft groove configuration. 1

FIG. 4 is a transverse sectional view like FIG. 2, but illustrating how the scuba tank can be refilled even though the reserve valve is set to the normal, nonreserve position.

FIG. 5 is a partial transverse sectional view like FIG. 4, illustrating the flow of air from the scuba tank with the reserve valve in the normal position.

DESCRIPTION OF THE PREFERRED EMBODIMENT -As shown in FIG. 1, the reserve valve mechanism 10 is used in conjunction with a scuba tank 11 containing air or other breathable gas. With the control handle 12 in the normal or non-reserve position shown in FIGS. 1, 4 and 5, air from the tank 11 is supplied via a conventional scuba regulator first stage 13 and a hose 14 to the demand valve on the divers mouthpiece 15.

The'pressure in the tank 11 ordinarily drops in response to the consumption of breathable gas by the diver. When only a small amount of air remains in the tank 11, the pressure will be insufficient to open a valve 16 in the reserve mechanism 10, resulting in an interruption of air flow to the diver. The diver will recognize from this interruption that his supply is almost exhausted, and will rotate the control handle 12 to the reserve positiontFIG. 2) which permits the remaining air in the tank 11 to flow to the mouthpiece l5. Accordingly, the diver can breathe this reserve air while ascending to the surface. A feature of the reserve valve mechanism 10 concems operation during refilling of the tank 11. Normally the tank 11 is filled by removing the regulator 13 and connecting an air compressor 18 or other high pressure source of breathable gas to the tank 11 via a hose 19 and the reserve mechanism 10. Unlike prior art units, the inventive reserve mechanism 10 permits the tank 11 to be refilled regardless of inlet passageway 23 facilitates air flow between the tank 11 and the valve 16 which is situated within a bore 24 communicating to an outlet 25. In the embodiment shown, the regulator 13 is connected to the reserve mechanism by a threaded coupling 26 received in the outlet 25.

An annular shoulder 27 separates the bore 24 from the outlet and serves as a stop for a generally annular valve seat member 28 which is slidable within the bore 24. A valve stem 29 extends loosely through the opening 30 in the valve seat member 28, and terminates at a valve head 31 having a diameter greater than the opening 30. The valve head 31 closes against the valve seat 28a to block air fiow between the tank 11 and the outlet 25. The valve seat member 28 is biased toward the shoulder 27 by a spring 32 situated in thebore 24 and surrounding the stem 29. As described below, the member 28 abuts against the shoulder 27 when air is being supplied from the tank 11 in either the normal or reserve condition. As shown in FIG. 4, the valve seat member 28 is forced away from the shoulder 27 when the tank 11 is being refilled with the control handle 12 in the normal" position.

The position of the valve stem 29 is controlled by a cam shaft 34 and a sliding cam follower 35 situated within the bore 24. The cam shaft 34 is rotated by the handle 12. The cam shaft interior end 34a includes a pair of diagonally aligned, relatively shallow grooves 36 and a pair of diagonally aligned, relatively deep grooves 37 which are perpendicular to the grooves 36. A pair of diagonally aligned cam lobes 38 project from the rear of the cam follower 35 and seat in either the

grooves

36 or 37 depending on the position of. the camshaft 34. Rotation of the cam follower 35 is prevented by a flat block 39 cooperating with a flat cam follower surface 40. The valve stem 29 is threaded to a tension adjusting nut 41 situated in a recess 42 within the cam follower 35. The bias spring 32 presses the nut 41 against an adjusting screw 43 contained in a central opening 44 in the cam follower 35 between the radially disposed cam lobes 38. With this arrangement, when the handle 12 is turned to the normal position (FIG. 5), the cam lobes 38 seat in the deep grooves 37. The spring 32 biases the valve seat member 28 against the shoulder 27, and urges the valve head 31 toward a closed position against the valve seat 28a. However, if considerable air remains in the tank 1 1, the air pressure exerted in the direction of the arrows 45 will be sufficient to displace the valve head 31 away from the seat 28a. There will be unimpeded air flow from the tank 1 1 via the reserve mechanism 10 to the regulator 13 and the mouthpiece 15.

As the air in the tank 11 is consumed, the pressure exerted against the valve head 31 will decrease. Eventually the pressure will drop to a level which will not overcome the force of the bias spring 32. When this occurs, the spring 32 will force the valve head 31 against the valve seat 28a, closing the valve 16 and interrupting the flow of air to'the diver. The diver will recognize from this interruption that only a limited amount of air remains in the tank 11. Typically, the spring force is adjusted using the nut 41 so that the valve 16 will close when the tank pressure drops to about 300 psi for regular diving. However, for repetitive dives, cave diving or other applications where an elongated reserve is advantageous, the adjustment may be made so that the valve 16 will close at say 600 psi.

When the diver senses the interrupted flow indicating that the reserve level has been reached, he rotates the control handle 12 to the reserve position shown in FIG. 2. In this orientation, the cam lobes 38 seat within the shallow grooves 36, so that the cam follower 35 maintains the valve head 31 away from the valve seat 28a; That is, the valve 16 is opened to permit the air remaining in the tank 11 to flow freely toward the regulator 13 as indicated by the arrows 46.

To refill the tank 11, the regulator first stage 13 (FIG. 1) is disconnected from the reserve mechanism 10, and the air compressor 18 is connected via the hose 19 and a coupling 48 (FIGS. 1 and 4). If the control handle 12 of the reserve mechanism 10 is in the reserve" position (FIG. 2), the valve 16 is open and air can flow freely from the compressor 18 to the tank 11, in a direction opposite that indicated by the arrows 46.

If the control handle 12 is in the normal position, the spring 32 will bias the valve 16 toward a closed position. However, as shown in FIG. 4, pressure of the air from the compressor 18 will act against the valve seat member 28, overcoming the counterforce exerted by the spring 32 and forcing the member 28 to slide away from the shoulder 27. The valve head 31 will remain stationary, since it is restrained by the cam follower 35. As a result, the valve 16 will open and the high pressure air will flow from the compressor 18 into the tank 11, as indicated by the arrows 49. Thus the tank 11 can be filled regardless of whether the control handle 12 is in the normal or reserve position. The adjusting screw 43 is used to insure that the valve head 31 abuts firmly against the valve seat 28a when the control handle 12 is in the normal position and the air pressure in the tank 11 is less than the force exerted by the spring 32. The valve seat member 28 is provided with an O-ring 50 to prevent escape of air from between that member and the bore 24. A pressure spring 51 and a tension nut 52 cooperate to compress a pair of packing

discs

53, 54 between the housing 21 and the cam shaft 34 and control handle housing 12a respectively. This prevents the escape of air pastthe cam shaft 34.

Intending to claim all novel, useful and unobvious features shown or described, the inventor makes the following claims:

1. A reserve mechanism for use with a self contained breathing apparatus, said mechanism including a valve situated on the flow path to a tank supplying breathable gas to other components of said breathing apparatus, the improvement wherein said valve includes two cooperating members situated in a closed, flowcommunicating interior chamber of said mechanism, said members being biased to close against each other to block the flow of gas through said chamber, said chamber having a first port on one side of said valve and connectable to said tank and a second port on the other side of said valve and connectable to said other components or to a source of high pressure breathable gas, one of said members opening in a first direction when the pressure of gas from said tank, entrant said chamber via said first port, exceeds a preset level to permit gas flow to other components of said breathing apparatus, the other of said members opening in the opposite direction when subjected to the pressure of gas from said high pressure source, entrant said chamber via said second port, to permit gas from said source to flow in the reverse direction through said chamber to refill said tank even though said valve has not been unimpeded flow of reserve air from said tank at less than said preset pressure.

2. A reserve valve mechanism for use with a selfeontained breathing apparatus having a tank for breathable gas, comprising:

a valve including a piston member having a valve head and'an annular valve seat member, said piston member being movable with respect to said valve seat member only in a first direction, said valve seat member being movable only in the opposite direction with respect to said piston member, relative motion'of either said piston or valve seat member conditioning said valve between a closed position in which said valve head abuts against said seat member to close the opening therethrough, and anopen position in which said valve head is spaced from said seat member,

means biasing said piston member toward said closed position, and

means for connecting said tank to other components of said breathing apparatus or to a high pressure source of breathable gas via said valve, the pressure of breathable gas from said tank, when in excess of the force of said biasing means, causing one of said valve members to move, opening said valve and permitting gas flow from said tank to said other components, the pressure of gas from said source causing the other of said valve members to move to open said valve and permit gas flowing from said source to refill said tank.

3. A reserve valve mechanism according to claim 2 shoulder to limit movement of said valve seat member, said cam operated means being disposed within said housing and including a cam follower slideably disposed in said interior bore.

5. A reserve valve mechanism according to claim 4 wherein said piston member includes a valve stem exa mounted within said bore, said bore having an interior tending loosely through the opening in said valve seat member and operatively engaging 'said cam follower, said valve head being situated on the same side of said valve seat member as said shoulder, said cam follower being situated on the opposite side of said valve seat member as said shoulder, said biasing means comprising a spring situated within said interior bore between said valve seat member and said cam follower.

6. A reserve valve mechanism according to claim 5 wherein said cam operated means further includes a cam shaft within said interior bore and connected to a control handle extending exteriorly of said housing, said cam shaft cooperating with said cam follower to control the position of said piston member in response to the orientation of said control handle.

7. A reserve valve mechanism according to claim 6 wherein said housing includes an inlet passageway communicating to said interior bore between said valve seat member and said cam follower and adapted for connection to said tank, and an outlet communicating to said interior bore from the side of said valve seat member facing said valve head, said outlet being adapted for connection either to said other components or to said source of breathable gas.

' 8. A scuba reserve mechanism facilitating the refilling of a scuba breathable gas supply tank regardless of whether the mechanism is in the reserve or normal position, comprising:

a housing having one port for connection to said supply tank and another port for connection either to a scuba regulator or to a refill source of breathable gas, there being a flow communicating path within said housing between said one and other ports,

a reserve valve situated in flow-blocking relationship in said flow communicating path, said reserve valve normally being biased to a closed position, but being openable by the pressure of gas entrant through said one port from said tank when said pressure is above a preselected value to permit flow of such gas from said tank tosaid regulator, and

a valve component also situatedin flow-blocking relationship in said path, said valve component being biased to a closed position, said valve being openable by the pressure of gas entrant through said other port when said pressure exceeds a certain value to permit refilling of said tank from said source even though said reserve valve remains biased to said closed position.

Claims

1. A reserve mechanism for use with a self contained breathing apparatus, said mechanism including a valve situated on the flow path to a tank supplying breathable gas to other components of said breathing apparatus, the improvement wherein said valve includes two cooperating members situated in a closed, flowcommunicating interior chamber of said mechanism, said members being biased to close against each other to block the flow of gas through said chamber, said chamber having a first port on one side of said valve and connectable to said tank and a second port on the other side of said valve and connectable to said other components or to a source of high pressure breathable gas, one of said members opening in a first direction when the pressure of gas from said tank, entrant said chamber via said first port, exceeds a preset level to permit gas flow to other components of said breathing apparatus, the other of said members opening in the opposite direction when subjected to the pressure of gas from said high pressure source, entrant said chamber via said second port, to permit gas from said source to flow in the reverse direction through said chamber to refill said tank even though said valve has not been opened manually, said mechanism also having control means for manually opening said valve to permit the unimpeded flow of reserve air from said tank at less than said preset pressure.

2. A reserve valve mechanism for use with a self-contained breathing apparatus having a tank for breathable gas, comprising: a valve including a piston member having a valve head and an annular valve seat member, said piston member being movable with respect to said valve seat member only in a first direction, said valve seat member being movable only in the opposite direction with respect to said piston member, relative motion of either said piston or valve seat member conditioning said valve between a closed position in which said valve head abuts against said seat member to close the opening therethrough, and an open position in which said valve head is spaceD from said seat member, means biasing said piston member toward said closed position, and means for connecting said tank to other components of said breathing apparatus or to a high pressure source of breathable gas via said valve, the pressure of breathable gas from said tank, when in excess of the force of said biasing means, causing one of said valve members to move, opening said valve and permitting gas flow from said tank to said other components, the pressure of gas from said source causing the other of said valve members to move to open said valve and permit gas flowing from said source to refill said tank.

3. A reserve valve mechanism according to claim 2 further comprising: cam operated means for manually moving said valve to said open position to permit unimpeded flow of gas from said tank to said other components when the pressure of gas from said source is less than the force of said biasing means.

4. A reserve valve mechanism according to claim 3 wherein said valve is contained in a housing having an interior bore, said valve seat member being slidably mounted within said bore, said bore having an interior shoulder to limit movement of said valve seat member, said cam operated means being disposed within said housing and including a cam follower slideably disposed in said interior bore.

5. A reserve valve mechanism according to claim 4 wherein said piston member includes a valve stem extending loosely through the opening in said valve seat member and operatively engaging said cam follower, said valve head being situated on the same side of said valve seat member as said shoulder, said cam follower being situated on the opposite side of said valve seat member as said shoulder, said biasing means comprising a spring situated within said interior bore between said valve seat member and said cam follower.

8. A scuba reserve mechanism facilitating the refilling of a scuba breathable gas supply tank regardless of whether the mechanism is in the reserve or normal position, comprising: a housing having one port for connection to said supply tank and another port for connection either to a scuba regulator or to a refill source of breathable gas, there being a flow communicating path within said housing between said one and other ports, a reserve valve situated in flow-blocking relationship in said flow communicating path, said reserve valve normally being biased to a closed position, but being openable by the pressure of gas entrant through said one port from said tank when said pressure is above a preselected value to permit flow of such gas from said tank to said regulator, and a valve component also situated in flow-blocking relationship in said path, said valve component being biased to a closed position, said valve being openable by the pressure of gas entrant through said other port when said pressure exceeds a certain value to permit refilling of said tank from said source even though said reserve valve remains biased to said closed position.