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Publication numberUS3526102 A
Publication typeGrant
Publication dateSep 1, 1970
Filing dateAug 21, 1968
Priority dateAug 25, 1967
Also published asDE6753599U
Publication numberUS 3526102 A, US 3526102A, US-A-3526102, US3526102 A, US3526102A
InventorsBoylett William F, Hill Joseph William, Leamon Tom B, Shaw George
Original AssigneePilkington Brothers Ltd
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Pumping and cooling system
US 3526102 A
Images(5)
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Description  (OCR text may contain errors)

p 1970 w. F. BOYLETT ET AL 3,526,102

PUMPING AND COOLING SYSTEM Filed Aug. 21, 1968 5 Sheets-Sheet l A nvenlo M L L) ,W

Sept. 1, 1970 w. F. BOYLETT ET AL 3,526,102

PUMPING AND COOLING SYSTEM I Filed Aug. 21. 1968 5 Sheets-Sheet 2 Sept. 1, 1970 w. F. BOYLETT ET AL 3,526,102

PUMPING AND COOLING SYSTEM Filed Aug. 21, 1968 5 Sheets-Sheet 5 Se t. 1, 1970 w. F. BOYLETT ET AL 3,526,102

PUMPING AND COOLING SYSTEM 5 SheetsSheet 4 Filed Aug. 21, 1968 A Inventors Sept. 1, 1970 w. F. BOYLETT ET AL 3,526,102

PUMPING AND COOLING SYSTEM Filed. Aug. 21. 1968 s Sheets-Sheet 5 United States Patent Office 3,526,102 Patented Sept. 1, 1970 3,526,102 PUMPING AND COOLING SYSTEM William F. Boylett, Ormskirk, Joseph William Hill, Saint Helens, Tom B. Leamon, Ormskirk, and George Shaw, Bickerstaif, England, assignors to Pilkington Brothers Limited, Liverpool, England, a corporation of Great Britain Filed Aug. 21, 1968, Ser. No. 754,283 Claims priority, application Great Britain, Aug. 25, 1967, 39,195/ 67 Int. Cl. F25d 23/12; B67d 5/62 US. Cl. 62-259 ABSTRACT OF THE DISCLOSURE A pumping and cooling system for a protective suit comprises a coolant circuit including passages in the suit and a flow passage in heat exchange with an evaporating refrigerator; and a reciprocating pump in the circuit is operated by pressure fluid from the refrigerant through valve means having two settings corresponding to the two strokes of the pump and operated cyclically by changeover means.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to pumping and cooling systems for circulating coolant in a closed fluid circuit, including, for example, coolant channels in protective clothing.

Description of the prior art A well known form of protective clothing for wear by personnel who are required to work in uncomfortably hot surroundings or in areas exposed to intense heat radiation, has a lining provided with channels through which a coolant, usually a liquid, is circulated by an external pump. Associated with the pump is a refrigerating unit for extracting heat from the coolant. Usually the pump and refrigerating unit are provided in a static installation located outside the high temperature working area, but this is unsatisfactory where personnel need to have a high degree of mobility as it is necessary to link the protective clothing with the static installation by fluid supply and return lines.

One object of the present invention is to provide a pumping and cooling system which may be compact and of lightweight construction, so that when it is employed to circulate coolant in protective clothing as described above it may be carried by the wearer of the protective clothing, thereby freeing the apparatus of any connection to an external static installation.

SUMMARY A pumping and cooling system according to the present invention comprises a sealable vessel arranged in heatexchange relationship with a coolant flow passage which is adapted to form part of a coolant circuit, said vessel being adapted to contain an evaporating refrigerant which releases pressure fluid upon absorption of heat, a fluid pressure-actuated reciprocating pump connected in the coolant circuit, and having a control connection to the vessel for supplying pressure fluid to control the pump, valve means in the control connection between the vessel and the pump and having two settings corresponding to induction and delivery strokes of the pump, and changeover means effective to change the setting of the valve means cyclically so that the pump effects continuous reciprocation.

The system according to the invention is readily adaptable for portable use, as for continuous operation of the pump it is necessary only to provide a suitable heat-absorb- Claims ing medium in the vessel. Such a medium preferably comprises a solidified or liquefied gas exposed to a temperature in excess of its sublimation or boiling temperature. Solid carbon dioxide is particularly suitable as its sublimation point is below normal atmosphere temperature.

In a preferred embodiment the valve means has two fluid outlets and is operable to supply pressure fluid from the sealable vessel to the two outlets in turn.

Desirably the changeover means is connected to a movable part of the pump and is effective automatically when the pump is at the end of a stroke to change the setting of the valve means so that the pump commences the next stroke.

Preferably a change of setting of the valve means is effected by the application of fluid pressure controlled by the changeover means, the changeover means being effective to provide a communication between said vessel and a fluid inlet associated with said valve means, at which inlet fluid pressure can be applied to effect a change of setting of the valve means.

The valve means according to one preferred embodiment of the invention comprise a spool valve movable axially in a housing, the changeover means being effective to provide selectively a communication between said vessel and a fluid inlet at one end of said housing, and between said vessel and a fluid inlet at the other end of said housing, a change of setting of the valve means being effected by application of fluid pressure at the fluid inlet at the appropriate end of said housing to move the spool valve axially.

In an alternative preferred embodiment the valve changeover means comprise sealing means mounted for movement with the pump and arranged to block an exhaust port when the pump is at the end of a stroke, a duct providing communication between said exhaust port and said vessel, and having a control outlet communicating with said duct at which fluid pressure can be applied to effect a change of setting of the valve means, whereby when said exhaust port is blocked by the sealing means fluid pressure is applied at said control outlet to cause a change in setting of the valve means.

In such an embodiment the system may include a first duct having an exhaust outlet and communicating with a control outlet at which fluid pressure can be applied to change the valve means from a first setting to a second setting, and a second duct having an exhaust outlet and communicating with a control outlet at which fluid pressure can be applied to change the valve means from said second setting to said first setting, said first and second ducts communicating with said vessel, and wherein the pump has associated therewith respective sealing means effective to block the exhaust outlets of said first and second ducts when the pump is respectively at the end of a pumping stroke and an induction stroke, so that fluid pressure is applied to the first and second control outlets alternately.

The sealable vessel preferably comprises a container for the evaporating refrigerant enclosed in a jacket which defines with the container said coolant flow passage.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagrammatic cross-section of pumping apparatus in a preferred embodiment of the invention;

FIG. 2 illustrates diagrammatically and partly in section a combined pumping and cooling system incorporating the apparatus of FIG. 1;

FIGS. 3A and 3B illustrate diagrammatically a combined pumping and cooling system according to an alternative embodiment of the invention, and

FIG. 4 is a diagrammatic cross-section through an alternative form of pumping apparatus for use in a system according to the invention.

3 DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, a fluid-operated pumping apparatus includes a positive displacement diaphragm pump comprising a pump chamber 11 one wall of which is constituted by a flexible diaphragm member 12. A fluid inlet 13 and outlet 14 communicate with the pump chamber 11 by way of respective inlet and outlet non-return valves 13', 14'. A pump actuating rod 16 is attached to the centre of the diaphragm member 12, reciprocation of the rod 16 flexing the diaphragm member 12 to cause induction of fluid through the inlet 13 and expulsion of fluid through outlet 14 on outward and inward strokes of the rod respectively.

At its end remote from the diaphragm member 12 the actuating rod 16 is connected to a driving piston 17 which is mounted for sliding movement in a cylinder 18. The piston 17 divides the interior of the cylinder 18 into two spaces 19, 20 and provides a seal between said spaces. The spaces 19, 20 communicate through respective conduits 21, 22 with valve means 23 shown generally enclosed in broken lines.

The valve means 23 comprises in this embodiment two respective three-way rotary valves 24, 25 having respective cylindrical plugs 26, 27 mounted rotatably and fluidtightly in respective cylindrical housings 28, 29. Each plug 26, 27 has a respective L-shaped flow passage 30, 31 therethrough and each valve housing 28, 29 is provided with three respective ports, spaced apart at 90 in the direction of rotation of the plug 26, 27, the central one of which communicates with a respective said conduit 21, 22, and the remaining two of which communicate 'respectively with fluid pressure inlet pipes 32, 33 and with exhaust outlets 34, 35 which vent to atmosphere. The valve plugs 26, 27 are rotatable within their respective housings 28, 29 by means of respective lever arms 36, 37 between two settings, in the first of which the respective passages 30, 31 provide communication between the respective conduits 21, 22 and the respective inlet pipes 32, 33, and in the second of which the passages 30, 31 provide communication between the respective conduits 21, 22 and the respective exhaust outlets 34, 35.

The valve lever arms 36, 37 are interconnected by a link 38 so that they are movable in unison, the valves 24, 25 being so arranged that, when one valve 24 is in its first setting, the other valve 25 is in its second setting, and vice-versa. The two fluid inlet pipes 32, 33 are connected to a common pressure fluid line 40.

The valve means 23 are mounted close to the actuating rod 16, the connecting link 38 extending parallel to and adjacent the rod 16. Attached to the link 38 at two spaced apart positions are respective fixed arms 41, 42 which project towards the rod 16 into the path of movement of a striker plate 43 aflixed to the rod 16.

Self-sustained operation of the pump 12 may be obtained simply by connecting the pressure fluid line 40 to a convenient source of fluid under pressure. Thus, assuming that the valves 24, 25 are disposed initially in their first and second settings respectively, as shown in FIG. 1, the pressure fluid line 40 will be connected to the space 19 through pipe 32, valve passage 30 and conduit 21, while the space 20 will be connected to the exhaust outlet 35 through the conduit 22 and the valve passage 31. The driving piston 17 will accordingly be moved in the sense of decreasing the volume of space 20, that is, downwardly as viewed in FIG. 1, urging the actuating rod 16 downwardly. The actuating rod 16 flexes the diaphragm member 12 inwardly, increasing the pressure in the pump chamber and forcing fluid therefrom through the outlet non-return valve 14.

On completion of its pumping stroke the diaphragm member 12 is disposed in the position shown in broken lines at 12', the striker plate 43 having engaged the arm 41 and moved it to the position shown in broken lines at 43'; this movement will have rotated the valve plug 26 and, through the connecting link 38, the valve plug 27, through so that the valves 24, 25 are now disposed in the second and first settings respectively. Pressure fluid is now supplied to the space 20 through the pipe 33, the valve passage 31 and the conduit 22, while the space 19 is exhausted through the conduit 21, the valve passage 30 and the exhaust outlet 34. Assuming, therefore, that the inlet fluid pressure is sufliciently greater than atmospheric to produce a resultant upward force on the piston 17 notwithstanding the smaller area of said piston exposed to the fluid pressure in the space 20, the piston 17 and actuating rod 16 will move in the opposite direction, that is, upwardly as viewed in FIG. 1. The diaphragm member 12 will be flexed outwardly, effecting an induction stroke of the pump 10 and drawing fluid into the chamber 11 through the inlet non-return valve 13'. On completion of this induction stroke the diaphragm member 12 will be in the position shown in broken lines at 12" and the striker plate 43 will have engaged the arm 42 and moved the latter to the position shown in full lines, the striker plate 43 occupying the position 43". The valves 24, 25 are thereby returned to their first and second settings respectively, and reversal of the direction of movement of the driving piston 16 again takes place to efiect a further compression stroke of the pump 10.

It will be appreciated that, provided the ratio of the fluid pressure applied to the line 40 to atmospheric pressure is greater than the ratio of the larger to the smaller area sides of the piston 17 by an amount suflicient to overcome friction between the piston 17 and the walls of the cylinder 18, the pumping apparatus will operate continuously, the pumping speed being dependent on the magnitude of the fluid pressure applied to the line 40.

The pumping apparatus is incorporated in a combined pumping and cooling system as a portable, self-contained cooling unit. Such a unit, employing the pumping apparatus of FIG. 1, is illustrated in FIG. 2, in which the pumping apparatus is indicated generally at P and a cooler device at C.

Fluid pressure is applied to the inlet pipe 40 of the apparatus P from a sealed cylindrical vessel 50 containing solid carbon dioxide. The vessel 50 is located coaxially within a cylindrical jacket 51 of larger diameter, so that a cooling space 52 is defined between the jacket 51 and the vessel 50. A respective inlet 53 and outlet 54 for a fluid to be cooled communicate with the interior of the jacket 51 at opposite ends thereof.

The fluid coolant, which conveniently is water containing an anti-freezing agent, is circulated in a closed circuit, including the cooling space 52 and an appliance to be cooled, by the pump 10, the outlet 14 of the pump being connected to the inlet 53 of the jacket 51. The appliance to be cooled comprises in this particular examample a protective suit 55 provided with coolant channels 56 through which the water is circulated after passing through the space 52.

The entire cooling and pumping unit is portable, most of the components of the pumping apparatus P and the cooler device C being made of lightweight metal such, for example as aluminium. Once charged with solid carbon dioxide the unit will operate continuously so long as, in practice, a minimum pressure of carbon dioxide of about 25 p.s.i. is maintained at the inlet pipe 40. In a typical unit of this type, the vessel 50 was charged with a 7 lb. block of carbon dioxide and the pumping apparatus P maintained a rate of flow of coolant water through a suit 55 of lbs. per hour for some 2 hours, the temperature difference between coolant water at the inlet to the unit and that at the outlet being 5 C. The total weight of this suit, including the initial carbon dioxide charge, was 35 lbs.

To facilitate replenishment of the carbon dioxide charge the vessel 50 is open at its upper end and provided with a quick-release cover plate 58 which seats on a continuous annular flange 59 provided externally of the vessel 50 at said open end, an annular sealing gasket 60 being disposed between the cover plate 58 and flange 59. The jacket 51 is also open at its upper end and provided at said end with a continuous external flange 61. The flange 59 of the vessel 50 is of suflicient radial extent to overlie the flange 61, an annular sealing gasket 62 being .disposed between the flanges 59 and 61. A bar 63 extends diametrically across the top of the cover plate 58. The bar 63 is formed with integral C-shaped hooked ends 64 and a clamping screw 65 is threaded in a bore extending perpendicular to the bar 63 mid-way between the hooked ends 64. When the vessel 50 has been charged with carbon dioxide, the cover plate 58 is placed in position and the bar 63 then moved across the cover plate in a direction perpendicular to its length until it extends along a diameter of the plate 58, the hooked ends 64 being engaged behind the flange 59. The clamping screw 65 is'then tightened, using a handwheel 65 so that it engages the cover plate 58 centrally, clamping both the plate 58 against the flange 59 and the flange 59 against the flange 61, and thereby sealing the cooler device C.

Although carbon dioxide is a particularly convenient cooling agent for the above-described application of the pumping unit, it will be appreciated that, in principle, other cooling agents, comprising either solidified or liquefied gases may be used, in conjunction with, of course, a suitable circulating coolant which does not freeze at the temperature of the cooling agent.

FIG. 3 illustrates an alternative embodiment of the invention, also designed for use as a self-contained portable cooling unit. The cooler device C is of the same construction as that of FIG. 2, and, as in the previous embodiment a coolant is circulated through the cooler device C and a suit 55 by a diaphragm pump 110.

In FIG. 3, however, the diaphragm pump 110 has a somewhat diflerent construction to that of FIG. 1. The interior of the pump chamber is constituted by a concave recess 111 formed in a block of metal (for example, aluminium), the diaphragm member 112 extending across this recess 111 to seal the pump chamber. A pump actuating rod 116 attached to the diaphragm member 112 is provided adjacent to the diaphragm member 112 with a boss 115 which has a convex surface 115' facing the diaphragm member 112 and secured thereto on the axis of the rod 116. The convex surface 115' conforms exactly in curvature with the concave recess 111 of the pump chamber.

As in the embodiment of FIG. 1 the pump actuating rod is connected to a double-acting driving piston 117 mounted in a cylinder 118 and dividing the interior thereof into two spaces 119, 120. A stop 119' is mounted on the end wall of the cylinder 118 in the space 119 and a further stop 120' is attached centrally to the piston.117 in the space 120. The stops 119', 120 limit the travel of the piston 117 on the induction and pumping strokes of the actuating rod 116 respectively.

A cam disc 143 is mounted on the actuating rod 116 between the boss 115 and the cylinder 118, and two respective control valves 124, 125 having respective actuating plungers 141, 142 are disposed adjacent the rod 116 so that the ends of said plungers 141, 142, which are provided with cam follower balls 141, 142', are located in the path of movement of the edge of the cam disc 143 (which is rounded) at the respective positions occupied by the disc 143 at opposite ends of the stroke of the driving piston 117.

Each control valve 124, 125 is of identical construction, having a cylindrical housing 128, 129 in which a valve member 126, 127 is slidably mounted. Each valve member 126, 127 has two spaced apart lands which make sealing contact with the internal wall of the respective housing 128, 129 and which define between them an annular space 130, 131. The wall of the housing 128, 129 is provided with two axially spaced apart ports connected respectively to a fluid pressure inlet 132, 133 and to atmosphere through an outlet 134, 1135, and intermediate these ports the said wall is provided with a port connected to a respective conduit 136, 137 leading to opposite ends of a cylindrical valve housing 138. Each valve member 126, 127 is urged by a spring 126', 127', in the housing 128, 129 into a position in which the respective actuating plunger 141, 142 is extended and the respective pressure inlet 132, 1133 is closed, the conduits 136, 137 being connected to the respective outlets 134, 135.

A spool valve 139 is mounted for axial sliding movement in the housing 138. The spool valve 139 has four axially spaced apart lands 139' which make sealing contact with the internal wall of the housing 138 and which define three axial spaced annular recesses 144, 145, 146 on the spool valve. The total length of the spool valve 139 is less than that of the housing 138 so that the spool valve 139 may occupy either of two settings in which it is urged against one or the other end wall of the housing 138 in dependence on the relative fluid pressures in the conduits 136, 137. The axis of the valve housing 138 is disposed horizontally so that the spool valve 139 remains in the position to which it is moved by such relative fluid pressures after the pressures in the conduits 136, 137 have equalised.

Five axially spaced ports are provided in the cylindrical wall of the valve housing 138; disposed centrally of the housing 138 is a fluid inlet port 140 communicating with a pressure fluid line 140; two ports 121', 1-22' are arranged symmetrically on each side of the port 140, and outwardly of the ports i121, 122' two exhaust outlet ports 134', 135' open to the atmosphere, are provided. The ports 134', 140' and 135' are in permanent communication with the annular recesses 144, 145, 146 respectively in 'both settings of the spool valve 139. The two ports 121', 122' communicate with respective conduits 121, I122 which in turn communicate with the first and second spaces 119, of the cylinder 118.

The fluid pressure inlets 132, 133 of the respective control valves 124, are connected in parallel with the pressure fluid line 140 which is in turn connected to a sealed vessel 150 containing solid carbon dioxide as a gas-generating and cooling agent. Coolant comprising water with an anti-freezing agent added thereto is circulated by the pump 110 in a closed fluid circuit including in series a jacket 152 surrounding the vessel 150 and a fluid-cooled suit 155. The coolant circuit, which is shown in broken lines, is identical to that of FIG. 2 and will not, therefore be described in detail.

The mode of operation of the pumping apparatus of FIG. 3 will be apparent from the foregoing description. Assuming that the ports have an initial position as illustrated in which the driving piston 117 is at the extreme left-hand end of the cylinder 118, and against the stop 119', then the cam disc 143 will be in engagement with the control valve plunger 141 forcing the valve member 126 inwardly against the action of the respective spring 126' so that the exhaust outlet 134 is closed and carbon dioxide under pressure is supplied to the conduit 146 from the inlet 132 by way of the annular space 130. The other conduit 137 remains connected to atmospheric pressure through the space 131 and outlet of the other control valve 125, and as a result the spool valve 139 is urged to the left-hand end of its housing 138 into afirst setting as shown in which carbon dioxide under pressure is supplied to the space 119 through the line 140, the inlet the annular recess 145, the port 121 and the conduit 121, while the space 120 is exhausted to atmosphere through the conduit 122, the port 122', the recess 146 and the outlet port 135'.

The driving piston 117 is therefore moved in the direction of decreasing the volume of the space 120, that is, to the right in FIG. 3, moving the boss 115 on the actuating rod 116 towards the recess 111 of the pump 110'. The pumping stroke of the pump 110 continues, coolant being expelled through an outlet non-return valve 114, until the diaphragm member 112 rests in surface-to-surface 7 contact with the recess 111, at which time the stop 120' abuts the respective end wall of the cylinder 118, as shown in broken lines.

On commencement of the pumping stroke, the cam disc 143 is moved by the actuating rod 116 out of engagement with the valve plunger 141, so that the valve member- 126 is returned by the spring 126 to the position in which it connects the conduit 136 to atmospheric pressure through the space 130 and outlet 134. Both conduits 136, 137 are now at atmospheric pressure, and the resultant axial force on the spool valve 139 is therefore zero. Since, however, the spool valve 139 is disposed horizontally, it remains in the setting shown until the completion of the pumping stroke, as described above.

When the diaphragm member 112 rests on the recess 111 on completion of the pumping stroke, the cam disc 143 engages the control valve plunger 142 and thereby forces the valve member 127 into the housing 129 until the outlet 135 is closed and the conduit 137 put into communication with the pressure fluid line 140 through the annular space 131 and the inlet 133. Carbon dioxide under pressure is now supplied to the left-hand end of the spool valve housing 138, causing the latter to move rapidly to the right into a second setting in which the pressure fluid line 140 communicates with the space 120 through the recess 145 and the conduit 122, while the space 119 is exhausted to atmosphere through the conduit 121 the space 144 and the outlet port 134'.

The driving piston 117 is now returned to the lefthand end of the cylinder 118, assuming of course that the carbon dioxide pressure is sufficiently greater than atmospheric pressure to move the piston 117 in this direction notwithstanding the smaller area of the piston 117 exposed to the pressure in the space 120. The actuator rod 116 is moved to the left, pulling the diaphragm member 112 outwardly, so that coolant is drawn into the pump recess 111 through an inlet non-return valve 113'. This induction stroke continues until the piston 117 encounters the stop 119, when the cam disc 143 will again engage and depress the valve plunger 141 to effect a changeover of the setting of the spool valve 139, as described above.

The pump 110 is therefore operated continuously as long as the carbon dioxide pressure is maintained.

The pumping apparatus shown in FIG. 4 comprises a cylindrical housing 159 with a central, inwardly projecting annular flange 160. Contained in the housing, and disposed co-axially therewith, is a movable actuator member comprising a central rod 161 carrying at opposite ends thereof disc elements 162 and 163. The disc elements 162 and 163 are carried centrally in respective flexible diaphragms 164 and 165 whose outer edges are secured and sealed to the housing 159. The disc element 162 has a downwardly projecting annular edge flange 166 which carries a rubber sealing ring 167, and the disc element 163 has a corresponding upwardly projecting annular edge flange 168 carrying a rubber sealing ring 169.

When the'actuator member is in its uppermost position (shown in FIG. 4) the sealing ring 169 abuts the lower face of the flange 160 and seals off an exhaust port 170 provided therein, a further exhaust port 171 in the upper face of the flange 160 being open. When the actuator member is in its lowermost position the sealing ring 167 abuts the upper face of the flange 160 and seals off the port 171, the port 170 then being open. The purpose of the ports 170 and 171 is explained later.

Secured to the housing 159 are upper and lower end plates 172 and 173 respectively. As can be seen from FIG. 4, the disc elements 162 and 163 and their associated diaphragms 164 and 165 eflectively divide the interior of the housing 159 into three chambers sealed from each other, namely an upper chamber between the end plate 172 and the diaphragm 164, a central chamber between 8 the diaphragms 164 and 165, and a lower chamber between the diaphragm and the end plate 173.

Coolant fluid to be pumped can enter the upper chamber through an inlet 174 having an associated non-return valve 175, and can be pumped from the upper chamber through an outlet 176 having an associated non-return valve 177. Gas under pressure can enter the lower chamber through an inlet 178. The central chamber with which the ports and 171 communicate, has a vent hole 179 leading to atmosphere.

A helical spring 180, disposed between the flange 160 and the disc element 163, urges the actuator member 161, 162, 163 downwardly.

In operation, the actuator member is urged downwardly in an induction stroke under the action of the spring 180, thereby increasing the volume of the upper chamber and drawing fluid thereinto through the inlet 174. Downward movement of the actuator member ceases when the sealing ring 167 abuts the flange 160. Gas under pressure is then introduced into the lower chamber through the inlet 178 to move the actuator member upwardly (against the action of the spring 180) in a pumping stroke. Such upward movement decreases the volume of the upper chamber, causing fluid therein to be pumped through the outlet 176, and continues until the sealing ring 169 abuts the flange 160. The actuator member then moves downwardly in a further induction stroke, the inlet 178 to the lower chamber then acting as an exhaust outlet.

The supply of gas under pressure to the lower chamber is controlled by a spool valve 181 mounted for axial sliding movement in a housing 182. The valve 181 has three axially spaced apart lands 183 which make sealing contact with the internal wall of the housing 182 and which define two axially spaced annular recesses 184 and 185 on the spool valve. The valve 181 may occupy either of two settings in which it abuts one or the other of the housing end walls. The housing 182 has end ports 187 and 188 at which gas pressure can be applied to eifect respective changes in setting of the 'valve 181.

Three axially spaced ports are provided in the cylin- 'drical wall of the housing 182; disposed towards one end of the housing 182 is a gas inlet port 189 communicating with a gas pressure line 190; a port 191 is disposed substantially centrally of the housing and communicates via a line 193 with the pump chamber inlet 178; and an exhaust outlet port 194 is disposed towards the other end of the housing. When the valve 181 is in the setting shown in FIG. 4, the annular recess 185 provides a communication between the inlet port 189 and the port 191. When the valve 181 is in its other setting, i.e. has been moved to the right as viewed in FIG. 4, the annular recess 184 provides a communication between the ports 191 and 194.

The gas pressure line 190 forms one arm of a cross junction, the opposite arm of which comprises a pipe 196 communicating with a source of gas pressure indicated as 197. A further arm of the junction is provided by a pipe 198, having a restrictor 199, and which communicates with a duct 200 in the pump housing 159 leading to the exhaust port 170. The pipe 198 has a control outlet 201 forming a T junction and communicating with the end port 187 of the spool valve housing 182. The fourth arm of the cross junction is provided by a pipe 202, having a restrictor 203, and communicating with a duct 204 in the pump housing 159 leading to the port 171. The pipe 202 has a control outlet 205 forming a T junction and communicating with the end port 188 of the spool valve housing 182.

At the end of a pumping stroke the sealing ring 169 blocks the port 170, as shown in FIG. 4. Gas pressure from the pipe 198 is therefore applied at the control outlet 201 and hence at the end port 187 of the spool valve housing. Since the port 171 is at this time open gas can flow from the pipe 202 through the duct 204 and the port 171 into the pumps central chamber, and therefrom through the vent hole 179, so that no substantial pressure is applied at the end port 188 of the spool valve housing. The greater pressure at the end port 187 therefore etfects a change of setting of the spool valve 181 by moving the latter to the right as viewed in FIG. 4. After such change of setting, the annular recess 184 provides a communication between the port 191 and the exhaust port 194. The actuator member is moved downwardly under the action of the spring 180 in an induction stroke, and during such movement, gas from the lower chamber of the pump flows to exhaust through the inlet 178, the port 191 and the exhaust port 194.

At the end of the induction stroke the sealing ring 167 blocks the port 171, the port 170 then being open. Gas pressure from the pipe 202 is therefore applied at the control outlet 205 and hence at the end port 188 of the spool valve housing. Since the port 170 is open gas can flow from the pipe 198 through the duct 200 and the port 170 into the pumps central chamber, and therefrom through the vent hole 179, so that no substantial'pressure is applied at the end port 187 of the spool valve housing. The greater pressure at the end port 188 therefore effects a change of setting of the spool valve 181 by moving the latter to the left as viewed in (and back to thei'position shown in) FIG. 4. After such change of settingfi the annular recess 185 provides a communication between the inlet port 189 and the port 191. Gas flows from the pressure line 190 to the port 191 and thence through the line 193 to the pump inlet 178, so that the actuator member moves upwardly in a pumping stroke.

The values of the restrictors 199 and 203 in the pipes 198 and 202 respectively are chosen to maintain a sufficient pressure of gas flow through the pressure line 190 to effect the required pumping operation notwithstanding flow through the pipes 198 and 202. It will be seen that during actual movement of the actuator member in a pumping stroke both of the ports 170 and 171 are open; the restrictors 199 and 203 present an impedance to the flow through these pipes from the pipe 196, andthereby to maintain a suflicient pressure in the line 190 to effect the pumping stroke.

The source of gas pressure, indicated at 197 in FIG. 4, is provided by solid carbon dioxide which absorbs heat from the coolant fluid pumped round a circuit including channels in a protective suit, in essentially the same manner as previously described in relation to FIGS. 2 and 3.

It should be noted that the combined pumping and cooling systems described above are to some extent selfadjusting. Thus if the temperature of the coolant should increase, due to an increase in the heat to which the associated protective suit is exposed, the rate of sublimation of carbon dioxide (or other cooling agent) in the sealed vessel which acts as the source of fluid pressure for the pumping apparatus will increase. Consequently* the gas pressure during the pumping apparatus will increase, thereby increasing the speed of operation of the pumping apparatus and, therefore, its pumping rate. The resulting increased rate of circulation of coolant will ISLllt in a lowering of the coolant temperature. The pumping rate will eventually adjust to a new level such thaflthe temperature difference between the coolant at the inlet and that at the outlet of the protective suit is maintained substantially constant.

In a modified form of apparatus according to the invention, the diaphragm pump 10, 110 in the embodiments of FIGS. 1 and 3 could be replaced by a positive displace ment pump of the reciprocating piston type; similarly, a diaphragm member could be used in place of the driving piston 17, 117.

We claim:

1. A portable, self-contained pumping and cooling system for an appliance comprising a coolant flow passage adapted to form part of a coOling circuit extending through the appliance, a scalable vessel arranged in heat-exchange relationship with the coolant flow passage which is adapted to form part of a coolant circuit, said vessel being adapted to contain an evaporating refrigerant which releases pressure fluid upon absorption of heat, a fluid pressure-actuated reciprocating pump connected in the coolant circuit, said pump comprising a pump chamber having an inlet and an outlet respectively fitted with inlet and outlet nonreturn valves, a diaphragm member forming a movable wall of the pump chamber, which member has its edge secured to the peripheral wall of the pump chamber and is adapted to flex so as to change the effective volume of the pump chamber to draw fluid into the pump chamber through said inlet during'lthe induction stroke of the pump and to discharge the fluid through said outlet during the pumping stroke, and an actuator member rigidly connected to said diaphragm member and housed in a second chamber and having a control connection to the vessel for supplying pressure fluid to move the actuator member to effect at least said pumping stroke of the pump, valve means second chamber and having two settings corresponding to v the induction and pumping strokes of the pump, and changeover means effective to change the setting of the valve means cylically SQ-that the moving members of the pump elfect continuous r' eciprocation.

2. A system according to claim 1, wherein the valve means has two fluid outlets to the second chamber and is operable to supply pressure fluid from the scalable vessel to the two outlets in turn thereby causing the actuator member to reciprocate and effecting the induction and pumping strokes of the pump.

3. A system according to claim 1, wherein the changeover means is connected to the rigid connection means between the moving members of the pump and is effective automatically when the'imoving members of the pump are at the end of a stroke to change the setting of the valve means so that the pump commences the next stroke.

4. A system according to claim 1, wherein a change of setting of the valve means is effected by the application of fluid pressure controlled by the changeover means, the changeover means being effective to provide a communication between said vessel and a fluid inlet associated with said valve means, at which inlet fluid pressure can be applied to effect a change'fof setting of the valve means.

5. A system according to claim 4, wherein the valve means comprise a spool valve movable axially in a housing, the changeover means being effective to provide selectively a communication between said vessel and a fluid inlet at one end of said housing, and between said vessel and a fluid inlet at the other end of said housing, a change of setting of the valve means being effected by application of fluid pressure at the fluid inlet at the appropriate end of said housing to move the spool valve axially.

6. A system according to claim 1, wherein spring means are provided to move the actuator member to effect the induction stroke of the pump.

7. A system according to claim 4, wherein the changeover means comprise sealing means mounted for movement with the moving members of the pump and arranged to block an exhaust port when the moving members of the pump are at the end of a stroke, a duct providing communication between said exhaust port and said vessel, and having a control outlet communicating with said duct at which fluid pressure can be applied to effect a change of setting of the valve means, whereby when said exhaust port is blocked by the sealing means fluid pressure is applied at said control outlet to cause a change in setting of the valve means.

8. A system according to claim 7, including a first duct having an exhaust outlet and communicating with a control outlet at which fluid pressure can be applied to change the valve means from a first setting to a second setting, and a second duct having an exhaust outlet and communicating with a control outlet at which fluid pressure can be applied to change the valve means from said second setting to said first setting, said first and second ducts communicating with said vessel, and wherein the pump has associated therewith respective sealing means effective to block the exhaust outlets of said first, and second ducts when the pump is respectively at the end of a pumping stroke and an induction stroke, so that fluid pressure is applied to the first and second control outlets alternately.

9. A system according to claim 1, wherein said scalable vessel comprises a container for the evaporating refrigerant enclosed in a jacket which defines with the container said coolant flow passage.

10. A system according to claim 1, wherein the appliance is a protective suit and wherein said coolant flow,

passage that is in heat exchange relationship with the 15 vessel, is connected to coolant flow passages in the protective suit.

References Cited UNITED STATES PATENTS 2,380,537 7/1945 McMechon 62384 2,383,486 8/1945 Isenberg 62384 2,760,345 8/1956 Woods 62-384 3,112,792 12/1963 Coleman 62259 10 WILLIAM J. WYE, Primary Examiner US. Cl. X.R. 62384

Patent Citations
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Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3670518 *Dec 21, 1970Jun 20, 1972Us NavyGarment cooling system
US3869871 *Apr 24, 1974Mar 11, 1975Didenko Nikolai SidorovichGas and heat protective garment
US4191028 *Jun 22, 1978Mar 4, 1980United States Of America As Represented By The Secretary Of The NavyDry ice, liquid pulse pump cooling system
US5435152 *Feb 18, 1994Jul 25, 1995Microcool CorporationAir treating device having a bellows compressor actuable by memory-shaped metal alloy elements
US6705111 *Jan 9, 2003Mar 16, 2004Rocky ResearchAmmonia-water absorption system with plunger-driven diaphragm solution pump
US7674281Sep 2, 2005Mar 9, 2010Forthright Engineering PllcApparatus and methods for providing a flow of a heat transfer fluid in a microenvironment
Classifications
U.S. Classification62/259.3, 165/46, 62/384, 165/85, 165/104.25
International ClassificationF01L33/04, F04B9/125, F01L25/06, F01L33/00, F04B9/127, F04B9/00, F01L25/00, F04B43/00, F01L23/00, F04B43/06
Cooperative ClassificationF01L25/063, F04B9/125, F01L23/00, F04B43/00, F04B9/127, F01L33/04, F04B43/06
European ClassificationF04B9/125, F01L23/00, F01L25/06B, F04B9/127, F04B43/00, F04B43/06, F01L33/04