GB1584808A - Breathing gas pump apparatus for divers - Google Patents

Description

(54) BREATHING GAS PUMP APPARATUS FOR DIVERS (71) We, WESTINGROUSE ELECTRIC CORPORATION, of Westinghouse Building, Gateway Center, Pittsburgh, Pennsylvania, United States of America, a company organised and existing under the laws of the Commonwealth of Pennsylvania, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The invention relates to breathing apparatus and more particularly to underwater breathing apparatus.

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 capsule, or the like, in which divers may spend time while submerged, presence of the pumps and their operating motors at the interior of the bell is space-demanding and may introduce an element of discom fort and a fire hazard to such divers.

It is the principal object of the invention to provide a smooth flow of breathing gas to a diver.

The invention consists in a breathing gas pumping apparatus for divers comprising: a plurality of reciprocating piston and cylin der type supply and return pumps, a first header means from which breathing gas is withdrawn by each of the supply pumps, a second header means into which breathing gas is discharged by each of the supply pumps, a third header means from which breathing gas is withdrawn by each of the return pumps, a fourth header means into which breathing gas is discharged by each of the return pumps, drive means for oper ating the pump pistons successively in an out-of-phase relationship with partial over lap between each two successive piston effected gas discharges and withdrawals, and a submersible shell enclosing said pumps, said header means and said drive means.

A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: 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 invention, curves depicting the out-ofphase operation of a group of four pump pistons, several of which groups are embodied in the apparatus of Fig. 1; Fig. 3 is a plan view, partly in outline and partly in section, of a preferred compact arrangement of components of the pumping apparatus of the present invention; Fig. 4 is a possible alternate arrangement of piston cylinders employed in the present invention; Fig. 5 is an exploded view of a multiple piston pump construction suitable for employment in the present invention;; 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 partly in section, of the breathing gas pumping apparatus of the present invention in affiliation with a diving bell, personnel transfer capsule, or the like, and a diver using the breathing gas via an umbilical and helmet.

Referring to Fig. 1, the breathing gas pumping apparatus 1 exemplified therein comprises four supply pump cylinders S1 to S4 and four return pump cylinders R1 to R4 arranged in groups of two in opposed fashion disposed along the axis 5 of a rotary drive shaft and of electric motor means 7 operatively affiliated co-axially with such shaft. Each cylinder has a piston 8 operably connected to the drive shaft for reciprocation 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 so as to be successively operated 90" out of phase with each successive one of the other supply pump pistons, and all supply pump cylin ders discharge breathing gas into a common supply header 10 via respective delivery lines 11. Correspondingly, each successive one of the four return pump pistons 8 is operated by the shaft 90" out of phase with each successive other and all return pump cylinders withdraw breathing gas from a common return header 12 via respective inlet lines 14.

In operation, the 90" out-of-phase discharge of the supply pump 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 exemplified by the curve ST in Fig. 2, hence yield a relatively quiet operation of the pumping apparatus as-experienced within the diving bell 15 (Fig. 7) 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 delivery lines 11 feeding such header volume have an inductive effect. By proper choice of header 10 volume, the sizes and lengths of lines 11, 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 operating speed of 1725 revolutions per minute, with a four-foot long header 10 two inches in diameter and delivery 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 pump cylinders R1 to R4 are operated 90" out of phase with each adjacent other to obtain a substantially pulse-free breathing gas return pressure condition in the diver return header 12 to which the return 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 cylinders S1 to S4 is availed of breathing gas from a source such as the interior of a diving bell, personnel transfer capsule 15, or the like, Fig. 7, by way of a supply line SFB, a supply inlet header 16, and supply inlet lines 17.

Similarly, the return cylinders R1 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 20 on the exterior of such bell. The usual means (not shown) automatically maintains the proper pressure of the breathing gas in the bell 15, as well as provides 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 pumping apparatus 1 at the exterior of the bell.A return umbilical hose RU also is employed in a push-pull system as exemplified in Fig. 7 for return of breathing gas from the diver D to the interior of the bell 15 via the control and monitor panel 24, the return hose DR, the pumping apparatus 1, and the line RTB.

It will be understood that when the diver D enters the bell 15, in accord with wellknown practice, he is free to remove his helmet and to breathe the gas within the bell. At such time, if the pumping apparatus 1 of the present invention continues in operation for accominodating 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, 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 vertically around the inner 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 passageway 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 that used by the diver. Another feature, Figs. 3 and 6, resides in the use of headers 10, 12, 16, and 18 of slim cylindri cal configuration extending vertically be tween the projecting heads of the pump cylinders S1 to S4 and R1 to R4.This, in addition to the axially distributed opposedpiston arrangement of such cylinders, affords a pump rod characterized with a high degree of compactness.

While the arrangement of supply and return pumps as depicted in Fig. 1 can be made to operate satisfactorily, it may be desirable to arrange all of the supply pumps in opposed piston fashion and all the return pumps in the same fashion, as shown schematically in Fig. 4. This gives a pressure balance on the piston heads in each opposed cylinder pair, S1 and S2, S3 and S4, R1 and R2, and R3 and R4, since it will be understood that all of the supply pump cylinders discharge to a common header means, and all the return pump cylinders withdraw from a common header means.

Furthermore, it should be pointed out that other numbers of cylinders each having a piston operating for 1800 of each crankshaft rotation, can be suitable for obtaining pulse-free operation of the overall apparatus; six cylinders at 600 intervals; five at 720; eight at 45" etc. During the remaining 1800 of each crankshaft revolution, 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 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 124, 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 .machine 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 piston actuation during 1800 of crankshaft rotation and that each is angulated 90" relative to the next-inline for the pressure-smoothing out-of-phase piston operation.

WHAT WE CLAIM IS: 1. Breathing gas pumping apparatus for divers comprising: a plurality of reciprocating piston and cylinder type supply and return pumps, a first header means from which breathing gas is withdrawn by each of the supply pumps, a second header means into which breathing gas is discharged by each of the supply pumps, a third header means from which breathing gas is withdrawn by each of the return pumps, a fourth header means into which breathing gas is discharged by each of the return pumps, 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 pumps, said header means and said drive means.

2. A breathing gas apparatus as claimed in Claim 1, wherein said shell has cooling fins 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 circulating of cooling gas past said cooling fins on said shell and past said pump cylinders.

3. A breathing gas apparatus as claimed in 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, said first and fourth header means being connected to the interior of said bell, and said second and third header means being connected to the diver's supply and return umbilical hoses, respectively.

4. Breathing gas pumping apparatus for divers, substantially as hereinbefore described with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (4)

**WARNING** start of CLMS field may overlap end of DESC **. tween the projecting heads of the pump cylinders S1 to S4 and R1 to R4. This, in addition to the axially distributed opposedpiston arrangement of such cylinders, affords a pump rod characterized with a high degree of compactness. While the arrangement of supply and return pumps as depicted in Fig. 1 can be made to operate satisfactorily, it may be desirable to arrange all of the supply pumps in opposed piston fashion and all the return pumps in the same fashion, as shown schematically in Fig. 4. This gives a pressure balance on the piston heads in each opposed cylinder pair, S1 and S2, S3 and S4, R1 and R2, and R3 and R4, since it will be understood that all of the supply pump cylinders discharge to a common header means, and all the return pump cylinders withdraw from a common header means. Furthermore, it should be pointed out that other numbers of cylinders each having a piston operating for 1800 of each crankshaft rotation, can be suitable for obtaining pulse-free operation of the overall apparatus; six cylinders at 600 intervals; five at 720; eight at 45" etc. During the remaining 1800 of each crankshaft revolution, 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 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 124, 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 .machine 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 piston actuation during 1800 of crankshaft rotation and that each is angulated 90" relative to the next-inline for the pressure-smoothing out-of-phase piston operation. WHAT WE CLAIM IS:

1. Breathing gas pumping apparatus for divers comprising: a plurality of reciprocating piston and cylinder type supply and return pumps, a first header means from which breathing gas is withdrawn by each of the supply pumps, a second header means into which breathing gas is discharged by each of the supply pumps, a third header means from which breathing gas is withdrawn by each of the return pumps, a fourth header means into which breathing gas is discharged by each of the return pumps, 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 pumps, said header means and said drive means.

2. A breathing gas apparatus as claimed in Claim 1, wherein said shell has cooling fins 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 circulating of cooling gas past said cooling fins on said shell and past said pump cylinders.

3. A breathing gas apparatus as claimed in 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, said first and fourth header means being connected to the interior of said bell, and said second and third header means being connected to the diver's supply and return umbilical hoses, respectively.

4. Breathing gas pumping apparatus for divers, substantially as hereinbefore described with reference to the accompanying drawings.