CA1081189A

CA1081189A - Breathing gas pump apparatus for divers

Info

Publication number: CA1081189A
Application number: CA289,363A
Authority: CA
Inventors: John R. Colston
Original assignee: DIVER'S EXCHANGE
Current assignee: DIVER'S EXCHANGE
Priority date: 1976-11-08
Filing date: 1977-10-24
Publication date: 1980-07-08
Also published as: DE2749958A1; JPS5359906A; GB1584808A; FR2369962A1; IT1091939B

Abstract

BREATHING GAS PUMP
APPARATUS FOR DIVERS

ABSTRACT OF THE DISCLOSURE
Breathing gas pumping apparatus for divers, with four or more fan-cooled supply piston pump cylinders arranged to discharge breathing gas in mutually out-of-phase relationship into a diver breathing gas supply header, together with four or more fan-cooled return piston pump cylinders arranged to withdraw breathing gas from a diver breathing gas return header in mutually out-of-phase relationship. The cylinders extend radially out-ward from a motor drive axis along which they are dis-tributed, and the headers are nested between projecting cylinder ends. The array is enclosed as a pod, by a cylindrical shell having cooling fins for transfer of heat from pump cooling gas circulating within the shell to the ambient liquid without.

Description

BACKGROUND OF THE INVENTION
Field of the Invention Breathing gas pumping apparatus for divers.
Description of the Prior Art Reciprocating piston type pumps for pumping breathing gas to and/or from a diver tend to be noisy due to their pulsating-type discharge, and when such pumps are located inside a diving bell, personnel transfer cap-sule, or the like, in which divers may spend time while submerged, presence of the pumps and their operating ~ I motors at the interior of the bell is space-demanding and may introduce an element of discomfort or fire hazard to ¦ such divers.

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~ 46,971 10811E~9 SUMMARY OF THE INVENTION
The present invention, by utllizing four or more mutually out-of-phase piston pump cylinders, con-structed and arranged to have some degree of overlap of ad~acent discharges at their beginnin~ and end, results in a substantially pulse-free supply and/or return pressure at the header and/or headers experienclng the - out-of-phase overlapping discharges and/or withdrawals as the case may be. At the same time, the cooled pod aspect enables the pump assembly to be mounted conveniently out-side the bell or capsule, thereby affording more space within the bell as well as a safer and more comfortable diver environment.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is an elevation view, partly in outline -and partly in section, of an illustrative embodiment of the breathing gas pumping apparatus of the present invention;
Fig. 2 shows, in accord with the present in-vention, curves depicting the out-of-phase operation of a group of four pump pistons, several of which groups are embodied in the apparatus of Fig. l;
Fig. 3 ls a plan view, partly in outline and - partly in section, of a preferred compact arrangement of components of the pump apparatus of the present invention;
Fig. 4 is a possible alternate arrangement of piston cylinders employed in the present invention;
Fig. 5 ls an exploded view of a multiple piston pump construction suitable for employment in the present lnvention;

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Fig. 6 is an elevation three-dimensional view of an embodiment of the invention with its cylindrical shell removed; and Fig. 7 is a schematic showing, partly in outline and partl~ in section, of the breathing gas pump apparatus of the present invention in affiliation with a diving bell, personnel transfer capsule, or the like, and a dlver using the breathing gas via an umbilical and helmet.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to Fig. l, the breathing gas pump apparatus l exemplified therein comprises four supply pump cylinders Sl to S4 and four return pump cylinders Rl to R4 arranged in groups of two in opposed fashion dis-posed along the axis 5 of a rotary drive shaft means 6 and of electric motor means 7 operatively affiliated co-axially with such shaft means. Each cylinder has a piston 8 operably connected to the shaft means 6 for reciproca-tion within a cylinder chamber to either discharge or withdraw breathing gas, as the case may be, via check valve means.
According to a feature of the invention, the four supply pistons 8 are operably affiliated with the drive shaft means 6 so as to be successively operated 90 out of phase with each successive one of the other supply cylinder pistons, and all supply cylinders discharge breathing gas into a common supply header 10 via respec-tive exhaust lines ll. Correspondingly, each successive one of the four return cylinder pistons 8 is operated by the shaft means 90 out of phase with each successive other and all return cylinders withdraw breathing gas from ~~' 46,971 10811~39 a common return header 12 via respective inlet lines 14.
In operation, the 90 out-of-phase discharge of the supply cylinders S1 to S4, as depicted by the curves in Fig. 2, when added together in the diver supply header 10 yield a substantially pulse free pressure condition therein, as exemplifled by the curve ST in Fig. 2, hence yield a relatively quiet operation of the pump apparatus as experienced within the diving bell 15 and by a diver using breathing gas from the diver supply header via a diver supply line DS. Attainment of such additive pulse cancellation in the supply header 10 for quiet operation of the system is dependent on operating parameters and design. The header volume has a capacitive effect on the periodic flow from the cylinders, and the exhaust lines 11 feeding such header volume have an inductive effect.
By proper choice of header 10 volume, line 11 sizes and lengths, etc., optimum muffling of the out-of-phase periodic breathing gas discharges for a particular total flow rate can be obtained.
For example, one particular test construction of the apparatus yielded satisfactory quieted performance at a total gas flow rate of three cfm at a piston operat-ing speed of 1725 revolutions per minute, with a four- ~ -foot long header 10 two inches in diameter and exhaust lines of one-half inch in diameter and lengths of six to eight inches.
Similarly, as in the illustrative embodiment shown in Fig. 1 where return pumping also is employed in the apparatus, the return pumps Rl to R4 are operated 90 out of phase with each ad~acent other to obtaln a sub-' - 46,971 108~1W

stantially pulse-free breathing gas return pressure condition in the diver return header 12 to which the re-turn umbilical from the diver is connected during use of the apparatus, via a diver's return line DR.
- As shown schematically in Fig. 1, each of the supply piston cylinders Sl to S4 is availed of breathing gas from a source such as the interior of a diving bell, personnel transfer capsule 15, of the like, Fig. 7, by way of a supply line SFB, a supply inlet header 16, and supply inlet lines 17.
Similarly, the return piston cylinders Rl to R4 discharge into a common return outlet header 18 via return exhaust lines 19. The return outlet header 18 in turn exhausts into the interior of the bell or capsule 15 via a line RTB, Fig. 7.
Referring to Fig. 7, the bell 15 is availed of breathing gas, such as a mixture of helium and oxygen, from bottles on the exterior of such bell. The usual -~
means (not shown) automatically maintains the proper pres-sure of the breathing gas in the bell 15, as well as pro-vides for removal of carbon dioxide introduced from the diver's breath,for oxygen level maintenance, etc., in a particular manner which, per se, forms no part of the present invention. The diver D when working outside the bell 15 is availed of breathing gas by way of such as a ; breathing helmet 21 affiliated with a wet suit 22, a back-pack chamber 23, a supply umbilical hose SU, a control and monitor panel 24, line SFB, and the pump pod apparatus 1 at the exterior of the bell. A return umbilical hose RU
also is employed in a push-pull system as exemplified in .

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Fig. 1 for return of breathing gas from the diver D to the interior of the bell 15 via the control and monitor panel 1~, the return hose DR, the pump apparatus 1, and the llne ~TB. It will be understood that when the diver D enters the bell 15, in accord with well-known practice, he is free to remove his helmet and to breathe the gas within the bell. At such time, if the pump apparatus 1 of the present invention continues in operation for accommodating another diver or other divers, its quiet operation is appreciated at the interior of the bell by the diver therein.
In accord with other features of the invention, the reciprocating piston cylinder array, including the headers 10, 12, 16, 18, motor means 7, lines 11, 14, 17, and 19 are enclosed in a cylindrical shell 25 having cooling fins 26 disposed in an annular passageway 27 extending vertlcally around the periphery of such shell.
An inner cylindrical wall 28 defines the inner wall of the passageway. The lower end of the cooling passageway opens into the bottom of the shell 25, which is closed ; by a bottom member 30, and the upper end of such passage-way opens to the top of such shell, which is closed by a top member 31. A fan means, not shown in Fig. 1, affiliated with the motor means 7, induces circulation of cooled gas from the bottom of the passageway upwardly past the motor means and pump cylinders to the top of the shell 25 and back down through such passageway past the cooling fins 26, which transfer heat to the outer shell and the ambient liquid surrounding it. Arrows 33 indicate such circulation of cooling gas, which can be the same as ` 46,971 1~ 8 that used by the diver Another feature, Figs. 3 and 6, resides in use of headers 10, 12, 16, and 18 of slim cylindrical configuration extending vertically between the pro~ecting heads of the pump cylinders Sl to S4 and Rl to R4. This, in addition to the axially distributed opposed-piston arrangement of such cylinders, affords a pump pod characterized with a high degree of compactness.
While the arrangement of supply and return cy-linders as depicted in Fig. 1 can be made to operate satisfactorily, it may be desirable to arrange all of the supply cylinders in opposed piston fashion and all the return cylinders in the same fashion, as shown schemati-cally in Fig. 4. This gives a pressure balance on the piston heads of each opposed pair, Sl and S2, S3 and S4, Rl and R2, and R3 and R4, since it will be understood that ;;~
all of the supply cylinders discharge to a common header means, and all the return cylinders withdraw from a common header means. ~
Furthermore, it should be pointed out that -; 20 other numbers of cylinders each having a piston operating for 180 of each crankshaft rotation, can be suitable for obtalning pulse-free operation of the overall assembly;
six cylinders at 60 intervals; five at 72; eight at 45;
etc. During the remaining 180 of each crankshaft revolu-tion, any particular piston will be functioning to induce the gas into the cylinder chamber, in the case of a supply cylinder, or to displace the gas from the cylinder chamber, in the case of a return cylinder.

Referring to Fig. 5, an exploded view of a four-cylinder pump assembly suitable for use in the present 46,971 ~.

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invention in Fig. 1 form is shown which comprises:
cylinder heads 119, head gaskets 120, outlet valves 121, valve plates 122, inlet valves 123, cylinder gaskets 12L~, cylinders 125, piston rings 126, piston seals 127, piston and piston rod assemblies 128, rider rings 129, eccentrics 130, keys 131, retaining rings 132, a clockwise fan 133, a counterclockwise fan 134, shrouds 135, shaft adapters 136, and miscellaneous machlne screws, etc., all in affiliation with the double-drive electric motor means 7.
In accord with the invention, it will be noted that each eccentric 130 is designed for plston actuation during 180 of crankshaft rotatlon and that each is angulated 90 relative to the next-in-line for the pressure-smoothing out-of-pha se pl ston op erati on .

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Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PRIVILEGE OR PROPERTY
IS CLAIMS ARE DEFINED AS FOLLOWS:

1. Breathing gas pumping apparatus for divers comprising:
a plurality of reciprocating piston-type supply and return pump cylinders, a first header means from which breathing gas is withdrawn by each of the supply pump cylinders, a second header means into which breathing gas is discharged by each of the supply pump cylinders, a third header means from which breathing gas is withdrawn by each of the return pump cylinders, a fourth header means into which breathing gas is discharged by each of the return pump cylinders, drive means for operating the pump pistons successively in an out-of-phase relationship with partial overlap between each two successive piston-effected gas discharges and withdrawals, and a submersible shell enclosing said cylinders, said header means and said drive means.

2. The breathing gas apparatus of claim 1, wherein said shell has cooling fin means affiliated with its inner surface for enhancing transfer of heat from the interior of the shell to the water at its exterior, and said apparatus further includes fan means urging circulation of cooling gas through said cooling fin means on said shell and past said pump cylinders.

3. The breathing gas apparatus of claim 1, further comprising a diving bell containing breathing gas and adapted to accept entry of a submerged diver, a diver's supply umbilical hose and a diver's return umbilical hose, and wherein, said first and fourth header means are connected to the interior of said bell and said second and third header means are connected to the diver's supply and return umbilical hoses, respectively.