Liquid flow apparatus

Abstract: Apparatus comprising a flow carrier (31) connectable in a liquid flow system including an electric motor-pump unit and a conduit for conveying a pumped liquid to a liquid utilization apparatus. The flow carrier (31) is connectable in the conduit and includes an opening which exposes the liquid flowing through the carrier. A heat sink or cold plate (51) is located on the carrier (31) over the opening, the heat sink (51) covering the opening and having a wet side exposed to the liquid. The heat sink further includes a dry side, and heat generating electrical control components (73,74) are secured to the dry side. A sensor (66) is also mounted on the heat sink and responds to a characteristic, such as the pressure, of the liquid. A heat insulating layer extends around the control components (73,74) and the sensor (66) and covers the dry side of the heat sink, the layer preventing condensation. The sensor and the control components are operable to control the motor-pump unit. In a domestic water supply system, for example, the liquid utilization apparatus includes the plumbing in a building. In a gasoline supply system, the liquid utilization apparatus comprises a gasoline dispenser.

Description: This invention relates generally to liquid flow apparatus. Pumping systems including electric motor-pump units are well known and in common use. Examples include residential water supply systems and gasoline dispensing systems in service stations. A typical water supply system includes amotor-pump unit in a well, a water pipe connected to the unit and extending out of the well to a pressure tank, and a control that senses the water pressure in the tank and controls the unit to maintain the pressure in a selected pressure range. Traditionally mechanical pressure gauges are used to monitor the flow pressure through such a system. Normally these pressure gauges are mounted on flow pipes whose pressures are to be monitored, using pipe stands or stubs. One popular method of mounting is to provide a bored hole in the pipe, the hole is then threaded, and then a small pipe stand or stub having male threads at one end and a pressure gauge on the opposite end is screwed into the hole. Flow pressure is transmitted to the pressure gauge through the pipe stub to the pressure gauge. There are numerous commercially available pressure sensors for use with pipe stubs. Most of these pressure sensors incorporate a chamber having a diaphragm with an inlet on one side of the diaphragm and an outlet on the other side of the diaphragm. The pressure sensing inlet normally has female threads for receiving male threads of the pipe stub and a narrow passage filled with a liquid, such as oil, is on the other side of the diaphragm. Water pressure in the pipe causes movement of the diaphragm which, in turn, moves the liquid in the stub on the other side of the diaphragm. Movement of this liquid in the narrow passage causes movement of an indicator to monitor pressure in the pipe. In the foregoing arrangement the small measuring passage located above the diaphragm often must be filled with oil. This presents a manufacturing problem because such a narrow passage is very difficult to fill with oil or any other liquid without leaving an air bubble therein. In order to properly fill such a gauge with the liquid needed for its functioning, it is therefore necessary first to apply a vacuum to the passage. It is an advantage of this invention that a pressure sensing mechanism is provided for a motor-pump system which can be easily mounted and filled but yet does not require the use of a filling oil and the need for pulling a vacuum. Some pressure sensor installations require on the site opening of the wall of a pipe on which the pressure gauge is installed. For example, some require holes in the walls of the pipes and some require protrusions in the walls of the pipes. Such operations are expensive and difficult to incorporate. Another advantage of this invention is that a pressure sensing mechanism is provided which when installed becomes in-line with the pipe line and is relatively inexpensive to manufacture and install. One prior art device for pipe pressure sensing comprises a part that defines a hollow chamber which is fastened onto a pipe to clamp a diaphragm between the pipe and a portion of the chamber unit surrounding a pressure inlet opening into the chamber. The diaphragm has a round, sensing protrusion with a sensing tip on an outer end thereof, which extends outwardly from one side of the diaphragm and extends through a round hole in the pipe so as to communicate the pressure in the pipe to the chamber. Although this design presents some improvement over the others, it also utilizes a mechanical interface among liquid, diaphragm, and liquid again to convey the pressure in the pipe to the gauge. It is another advantage of the present invention that it includes a mechanical-electrical transducer which more accurately measures the pressure in a motor-pump system. Various types of pipe pressure sensors can only be used with specific types of pipe, but it is an advantage of this invention that a pipe pressure sensor is provided which can be used with various types of pipe including both plastic and metal pipes. Control units for pump-motor units including electronics are typically cooled by air cooling through a metallic radiating panel used as a heat sink or a cooling plate. Various types of stock heat sinks are commercially available. Due to the low convective ability of air cooling, the size of such heat dissipating devices is relatively large compared with the overall size of the control package itself. The broad concept of cooling electrical devices by means of a flowing medium was introduced some time ago. In one particular design a closed recirculation cooling system was developed to cool electrodes at different electrical potentials. An advantage of the present invention is that the size of packaging is reduced by using a liquid cooling medium in lieu of the well known air cooling method. In another prior art design, a printed circuit board package for high density packaging includes electronic circuit components cooled by a liquid cooled cold plate or heat sink. A circulating coolant is also included. A compliant interface including a heat conductive and electrically insulative paste between the cold plate and the circuit components is provided. The paste, which flows like a highly viscous liquid, is used in conjunction with a deformable thin film to compensate for any variations or irregularities so as to conform with the surfaces of the individual circuit packages. US-A- 3 551 072 discloses apparatus having the pre-charactering features of each of claims 1, 24 and 27. According to the present invention from one aspect, there is provided liquid flow apparatus comprising: a) a pump for the liquid; b) an electric motor connected to drive said pump; c) pipework connected to said pump and operable to carry the pumped liquid to liquid utilization apparatus; and d) a control module for controlling said motor, said module comprising a flow carrier including a conduit connected in said pipework and operable to carry the liquid, said conduit having an opening in a side thereof, characterised in that said module further comprises: 1) a heat sink on said conduit and over said opening, said heat sink having a wet side exposed to the liquid and a dry side sealed from the liquid; and 2) at least one heat generating component mounted on said heat sink and cooled by said heat sink and the liquid. The apparatus could further include heat and electrical insulating material on said dry side of said heat sink, said material extending around the periphery of the heat generating component or components. The apparatus could further include clamp means extending across said dry side, said clamp means pressing the or each heat generating component against said dry side for securing the or each heat generating component to said heat sink. Said dry side of said heat sink may have an outer periphery, the apparatus including a frame extending adjacent said outer periphery of said dry side and such insulating material extending to said frame and around the heat generating component or components. A potting compound may cover the edge and lower portions of said clamp means. Said clamp means may comprise a strip which extends over the or each heat generating component and fasteners on opposite sides of the or each component for securing said strip to said heat sink, said strip including a protrusion adjacent the or each component for engaging and applying pressure on the component. The size of said opening may be in the range from 1.5 to 5.0 times the size of said conduit. Said conduit may include an enlarged portion, said opening being formed across said portion. Said enlarged portion may include rib means for accelerating the flow of liquid past said heat sink. Said flow carrier may be made of plastic and said heat sink of a high heat conductive material. Said control module may further include a housing on said flow carrier, said housing enclosing said heat sink and the or each heat generating component. The apparatus may further include seal means between said heat sink and said conduit for sealing said dry side from said wet side. Said conduit may include two ends by which it is connected in said pipework, such an enlarged portion and said opening being between said two ends and said conduit further including a substantially rectangular section between each of said ends and said enlarged portions. Each of said substantially rectangular sections may have a flat side which is substantially coplanar with said opening of said enlarged portion. Said ends of said conduit may be enlarged for connection in said pipework, being threaded for example for connection in said pipework. Said heat sink may have an opening therethrough from said wet side to said dry side, the apparatus further including a flexible diaphragm covering said opening and a sensor mounted on said dry side and engaging said diaphragm. Said sensor may comprise a pressure sensor. Said diaphragm may include seal means on an outer periphery thereof. Said seal means may comprise an O-ring formed integrally with said diaphragm. A seal clamp may encircle said diaphragm and compress said seal means against said heat sink to form a seal between said heat sink and said diaphragm. An annular groove may be formed in said seal clamp and/or said heat sink, said O-ring being located and pressed in said groove. Such apparatus may further comprise a sensor cup positioned over said diaphragm and said seal clamp and secured to said heat sink, said sensor being mounted within said sensor cup. According to the present invention from another aspect, there is provided apparatus for monitoring pressure in pipework, comprising a liquid flow carrier having inlet and outlet ends connectable with said pipework, an opening formed in said carrier between said ends, a plate fastened to said carrier over said opening and pressure sensing means, characterised in that said pressure sensing means has electronic circuitry, said pressure sensing means being mounted on said plate and exposed to pressure in said flow carrier, the apparatus further including seal means between said flow carrier, said plate and said pressure sensing means. Said plate may have an aperture formed therein, said pressure sensing means comprising a diaphragm covering said aperture and a pressure sensor engaging said diaphragm. The apparatus may further comprise pump means for producing liquid flow in said pipework and in said carrier, said pressure sensing means being operable to control said pump means. According to the present invention from another aspect, there is provided liquid flow apparatus including an electric motor for driving a pump, pipework connected to the pump for conveying the liquid to liquid utilization means and a module for controlling the motor, said module comprising a conduit connected in said pipework and forming a flow passage operable to carry the liquid in said pipework, characterised in that the apparatus further includes a heat sink on said conduit, said heat sink having one side exposed to said flow passage, and heat generating control components mounted on said heat sink, said control components being operable to control the pressure of the liquid in said conduit. Said control components may be operable to control the speed of the motor. Said module may further include pressure sensing means mounted on said heat sink and exposed to said flow passage, said control components being connected to said pressure sensing means and being operable to control the motor to maintain a selected liquid pressure range. Said heat sink may have an opening therein, said pressure sensing means including a diaphragm over said opening and exposed to said flow passage, the apparatus further including means engaging said diaphragm for providing a signal representing the liquid pressure on said diaphragm. According to the present invention from another aspect, there is provided a control module for controlling the speed of an electric motor of a liquid flow apparatus, the module comprising a plate made of a high efficiency heat conducting material, a plurality of electrical components mounted on one side of said plate, said components generating heat during operation of said module, flow means for moving the pumped liquid across the opposite side of said plate to cool it and a heat insulating layer on said one side of said plate and extending around said components, said layer being operable to secure said components to said plate and to prevent condensation from occurring on said one side of said plate. The module may further include a pressure sensor mounted on said one side of said plate for sensing the pressure of said cooling liquid, said layer extending around said pressure sensor. Said heat insulating layer may comprise a potting compound. Said electrical components may comprise a rectifier and a plurality of solid state switches, said switches being positioned in a row on said one side of said plate, each of said switches including a bottom side which is adjacent said plate and a top side which is opposite said bottom side, the module further including a clamp for securing said switches to said plate, said clamp comprising a strip which extends across said top sides of said switches and a plurality of fasteners between said switches for securing said strip to said plate and for pressing said strip against said switches. Such a module may further include a frame around the periphery of said plate, said clamp having its ends secured to said frame, a potting compound being within said frame and extending over the edge and lower portions of said clamp. In a domestic water supply system, for example, the liquid utilization apparatus includes the plumbing in a building. In a gasoline supply system, the liquid utilization apparatus comprises a gasoline dispenser. The invention will now be described, by way of example, with reference to the accompanying drawings, wherein: Fig. 1 is a schematic illustration of a domestic water supply system including apparatus according to an embodiment of the invention; Fig. 2 is an elevational view of a flow carrier of the apparatus; Fig. 3 is a plan view of the flow carrier; Fig. 4 is an exploded perspective view of the carrier; Fig. 5 is a top plan view of the carrier; Fig. 6 is a bottom plan view of the carrier; Fig. 7 is a sectional view taken on the line 7-7 of Fig. 5; Fig. 8 is a sectional view taken on the line 8-8 of Fig. 6; Fig. 9 is a sectional view taken on the line 9-9 of Fig. 6; Fig. 10 is an enlarged view of part of the carrier; Fig. 11 is a further enlarged sectional view taken on the line 11-11 of Fig. 10; and Figs. 12 to 15 show an alternative construction of a flow carrier. Fig. 16 is an exploded perspective view showing another and preferred apparatus in accordance with the invention; Fig. 17 is a plan view of a component clamp and potting guard of the apparatus of Fig. 16; Fig. 18 is a sectional view taken on the line 18-18 of Fig. 17; Fig. 19 is a sectional view taken on the line 19-19 of Fig. 17; Fig. 20 is a sectional view taken on the line 20-20 of Fig. 17; Fig. 21 is a plan view of a sensor cup of the apparatus of Fig. 16; Fig. 22 is a sectional view taken on the line 22-22 of Fig. 21; Fig. 23 is a sectional view taken on the line 23-23 of Fig. 21; Fig. 24 is a bottom view of the sensor cup; Fig. 25 is a view of one side of the sensor cup; Fig. 26 is a view of another side of the sensor cup; Fig. 27 is a plan view of a flow carrier of the apparatus of Fig. 16; Fig. 28 is a bottom view of the flow carrier of Fig. 27; Fig. 29 is a side view of the flow carrier of Fig. 27; Fig. 30 is a sectional view taken on the line 30-30 of Fig. 28; Fig. 31 is a sectional view taken on the line 31-31 of Fig. 27; Fig. 32 is a sectional view taken on the line 32-32 of Fig. 28; and Fig. 33 is a view taken on the line 33-33 of Fig. 29; While Fig. 1 illustrates a domestic water supply system, it will be apparent that the invention may also be useful in other areas. The water supply system includes a unit 10 including a pump 11 driven by an electric motor 12. The unit 10 is located in a well 13 containing water 14. The unit 10 is suspended in the well by a pipe 16 which also conveys the pumped water to the ground surface. A drop cable 17 connects electric power to the motor 12. At the surface, and normally within a home in a domestic water supply system, is located a control unit 21 that is connected to the pipe 16, as will be described. The pipe 16 is connected to fill a pressure tank 22 and to supply water to a pipe 23 of the plumbing of the residence. The cable 17 is also connected to the control unit 21, and the unit 21 controls the supply of electrical power from a typical AC power supply 24 such as a 220 volt, 60 cycle supply. In other types of systems, such as a gasoline pumping system of a filling station, for example, the pressure tank 22 would not be provided but other controls and sensors (not shown) may be provided. With reference to Figs. 2, 3 and 4, the control unit 21 includes a flow carrier 31 which is connected between the pipes 16 and 23. The carrier 31 includes a conduit 32 (see Fig. 8) including threaded couplings at its ends 33 for connections between the pipe 16 and the pipe 23, and it forms a flow passage 32a between the ends 33. At approximately the center of the carrier 31, the conduit 32 is enlarged to form a generally semi-spherical dome or bulb 36 which is solid on the underside (as seen in Figs. 2 and 4) and has a flat upper side with an opening therein. Between the bulb 36 and each of the ends 33, the conduit 32 is generally rectangular and has a flat side that is substantially coplanar with the flat upper side of the bulb. The ends 33 are enlarged and threaded for coupling with the pipe 23. In the example of the invention illustrated in Figs. 2-4, the carrier 31 includes a plate 41 which is formed integrally with the flat upper sides of the conduit 32 and the bulb 36. The carrier 31 may be formed of a cast or molded metal or suitable plastic such as a polymer, for example. As shown in Fig. 4, the opening in the upper side of the bulb 36 appears as a circle in the plate 41. An upwardly turned flange or rim 42 is formed around the periphery of the plate 41, and a cover 43 fits around the rim 42 and is fastened by bolts 44 to the carrier 31. The cover 43 is enlarged as indicated at 46 in the area above the bulb 36, and the parts 41 and 43 form an enclosure for a control package 47 including heat generating electronics. In Figs. 5, 6 and 7, the entire plate 41 is not illustrated; instead, only an annular portion of the plate 41, surrounding the opening of the bulb 36, is shown. The annular portion may be extended to form the entire bottom wall of an enclosure as shown in Fig. 3, or a separate enclosure may be mounted on top of the annular portion as shown in Figs. 12-15. A flat thermally conductive plate 51 (preferably made of metal) is positioned over the open upper side of the bulb 36 (see Figs. 4, 10 and 11) and forms a heat sink or cold plate. Around the open upper side of the bulb 36 is an annular seal groove 52, and a seal 53 (Figs. 4 and 10) is mounted in the groove 52 and forms a seal between the plate 41 and the underside of the cold plate 51 which in this instance is substantially square as shown in Figs. 4 and 10. A series of holes 54 are formed in the plate 51 and in the carrier 31 radially outside the seal 53, and screws secure the plate 51 to the plate 41. A hole 56 is formed in plate 51, and a sensor 57 is mounted on the plate 51 above the hole 56. In the present example, the sensor 57 comprises a liquid pressure sensor best shown in Fig. 11. An annular diaphragm 58 is positioned over the upper side of the hole 56, and an O-ring 59 is formed integrally with the outer periphery of the diaphragm. An annular diaphragm clamp 61 is positioned over the outer periphery of the diaphragm 58 and a groove 62 in the clamp receives the O-ring 59, thereby forming a seal around the hole 56, between the lower side of the clamp 61 and the upper side of the plate 51. A sensor cup 66 is positioned over the diaphragm clamp 61 and is secured to the plate 51 by screws 67, the cup 66 serving to hold the clamp 61 and the diaphragm 58 on the plate 51. The cup 66 forms a cavity 68 which contains and holds the sensor 57 which is positioned against the upper side of the diaphragm 58. The sensor 57, in this specific example, is a pressure sensor that produces an analog electric signal which is representative of the liquid pressure. The bottom side 69 of the sensor is accessible for pressure sensing and is pressed upwardly by the liquid pressure acting on the diaphragm 58. The sensor may, for example, be formed by a variable resistance strain gauge, or it may be formed by a variable resistor connected in a Wheatstone bridge arrangement. Electrical leads 71 are connected to the sensor 57 and extend out of the cup 66 through an opening 72. The control 47 further includes electronic components 73 and 74 which are secured to the upper dry side of the plate 51 by screws 76. The components 73 and 74 are power components which generate heat during use, and they are part of the control circuit for the motor 12. In the present example, the control circuit comprises a conventional DC link arrangement and the motor 12 is a three-phase synchronous variable speed motor. The component 74 comprises an AC to DC rectifier and the component 73 comprises a DC to variable frequency AC inverter. The power supply 24 (Fig. 1) is connected to the rectifier 74 and the output of the inverter 73 is connected to the drop cable 17 and to the motor 12. The pressure sensor 57 has its output signal connected in the DC link to control the frequency of the inverter output. The DC link preferably also includes ramp circuits, as is well known to those skilled in this art. It is an important feature of the present invention that the components in need of cooling are mounted directly on the upper side (the dry side) of the cold plate 51 and that the bottom side (the wet side) of the plate 51 is directly exposed to the liquid flowing through the conduit 32, and that the components in need of cooling control the motor 12 and the flow of the cooling liquid. Consequently, the cooling liquid flows while the components are generating heat. Further, the invention utilizes as a coolant a liquid which is being circulated for another purpose (i.e., the invention does not require a separate dedicated cooling arrangement). Further, the liquid acts essentially directly on the sensor 57 because only the diaphragm 58 is interposed between them. The semi-spherical dome or bulb 36 forms a relatively large opening and therefore the plate 51 has a large surface area in contact with the cooling liquid. Figures 3, 5, 7 and 9 show that the interior of the bulb includes a plurality of radial ribs 81a to 81f and a center post portion 82 which connects the radially inner ends of the ribs. As shown, for example, in Fig. 3, the radially outer ends of the ribs 81a and 81b connect with the bulb 36 on opposite sides of the inlet flow area of the conduit 32, and the ribs 81d and 81e also connect with the bulb 36 on opposite sides of the outlet flow area of the conduit 32. As shown in Fig. 7, the upper edges of the ribs taper downwardly toward the post 82 and are spaced from the lower side of the plate 51. The liquid enters the bulb 36 between the ribs 81a and 81b, flows through the flow area between the upper edges of the ribs and the plate 51, and flows out of the bulb between the ribs 81d and 81e. The flow area between the plate 51 and the upper edges of the ribs is preferably less than the flow area 32a (see Fig. 8) of the conduit 32, whereby the velocity of the liquid flow is increased underneath the plate 51. Further, the relatively large opening of the upper side of the bulb forms a relatively large area of the plate where the liquid cools (or draws heat away from) the plate 51. For example, the diameter of the opening of the bulb 36 is preferably in the range of from 1.5 to 5.0 times the outer diameter of the conduit 32. In addition to accelerating the liquid flow, the ribs also serve to strengthen the bulb. A plurality of radially extending strengthening ribs 86 (Figs. 2 and 6) may also be formed on the exterior of the bulb. Apparatus in accordance with the above example of the invention also has the following listed advantages: 1. A single integral package includes a control, heat sink and sensor. 2. It may be installed using ordinary plumbing tools. 3. It is compact in size but is high in cooling efficiency per unit area. 4. There is a direct sensing of liquid pressure by a mechanical-electrical pressure transducer or sensor. 5. It includes a one-piece flow carrier with liquid flow acceleration ability and ease of assembly. 6. A combined heat sink and pressure sensor are mounted in the same unit. 7. The sensor, electronic components and heat sink are concealed inside the module or package. 8. The package may be used with any type of piping system, such as metal or plastic. Figs. 12 through 15 show an alternative construction of the flow carrier and the housing for the power or control module and the pressure sensor. Whereas in Figs. 1 to 11, the bottom part of the housing is formed integrally with the flow carrier, in the embodiment shown in Figs. 12 to 15 they are separately formed. The flow carrier 101 of Figs. 12 to 15 comprises a tubular conduit 102 having threaded coupling portions 103 at its ends and an enlarged portion 104 in the shape of a semi-spherical bulb at its center. The upper side of the bulb 104 forms a round opening 106 and a generally circular flange 107 is formed around the opening 106. Exterior reinforcing ribs 108 (Figs. 12 and 14) are formed on the underside of the flange, between the flange and the bulb. A ring of mounting holes 109 are formed in the flange 107. The upper side of the flange 107 and the adjacent portions of the conduit 102 are flat, and the bottom wall of a housing 111 is positioned on the flat surface. An opening 112 having a general contour following the periphery of a cold plate 113 is formed in the bottom wall of the housing, and the plate 113 plus the housing 111 are secured to the carrier by bolts 114. A pressure sensor 116 and heat generating power control components 117 (Fig. 13) are mounted on the control plate 113, as described in connection with Figs. 2 to 11. While not illustrated, a cover is preferably mounted over the upper side of the housing 111. In other respects, the embodiment of the invention shown in Figs. 12 to 15 is essentially the same as that shown in Figs. 2 to 11 and has similar advantages. With reference to Fig. 16, another embodiment of the invention is shown, which has further advantages as will be described. A flow carrier 150 has a control box 151 attached to one side, and heat generating electrical control components 152 are mounted within the box 151. The carrier 150 has a flat upper surface 153 and the flat bottom wall 151A of the control box 151 engages the surface 153. A lengthwise elongated opening 154 (see Figs. 16 and 27) is formed in the flat surface 153, and a seal groove 156 is formed between two closed form parallel ribs 157 which surround the opening 154. An elongated hole 158 is formed through the bottom wall 151A, and the hole 158 is sized to receive the outermost of the two ribs 157, whereby the two ribs 157 extend through the hole 158. An O-ring 159 is positioned in the groove 156 and extends above the ribs 157 and into tight seal engagement with the flat underside of a heat sink or cold plate 161 (Fig. 16). A plurality of screws 162 (only one shown in Fig. 16) extend through holes 163 formed through the flat surface 153 on the outside of the ribs 157 and are threaded into holes in the underside of the plate 161. Thus, a liquid tight seal is formed around the opening 158, between the surface 153 and the plate 161. The seal 159 is located near the outer periphery of the plate 161 so that most of the bottom surface of the plate 161 is exposed to a liquid flowing through the flow carrier 150. The screws 162 secure the flow carrier 150 to the plate 161 and the edge portion of the bottom wall 151A, around the hole 158, is sandwiched between the surface 153 and the plate 161. Figs. 27 to 33 show further details of the flow carrier 150. A liquid flow passage 166 is formed through the carrier 150 between its ends 167, and hex surfaces 168 are provided adjacent the ends 167. The opening 154 is located approximately midway between the ends and the carrier is laterally widened around the opening 154. Strengthening ribs 169 are provided below the flat surface 153, and the passage 166 is shaped to cause the liquid flowing through the passage 166 to move across the bottom surface of the plate 161 which is directly exposed to the liquid, through the opening 154. The control box 151 (see Fig. 16) further includes side walls 176 which extend upwardly from the bottom wall 151A, and a cover 177 closes the interior of the box. The interior space of the box 151 is preferably sufficiently large to hold other electrical components (not illustrated) such as filters. The cold plate (or heat sink) 161 is made of a good heat conducting material such as pure copper. As previously described, heat generating electrical components 152 of a control circuit are mounted on the upper surface of the cold plate 161, and in the specific example being described herein, the control circuit includes a rectifier 181 and an inverter 182 of a DC link system. The rectifier 181 has a flat bottom surface which is held tightly against the cold plate 161 by a screw 183. The inverter 182 includes six solid state electronic switches 184, and the mounting of these switches will be described in more detail hereinafter. As illustrated in Fig. 16, a number of holes are formed in the cold plate 161, and with one exception, the holes either do not extend through the plate or are outside of the seal 159. Most of the holes are tapped to receive mounting screws. The one exception is the hole 186 which extends through the cold plate 161; the lower end of the hole 186 is exposed to the liquid in the flow passage 166 of the carrier 150, and the upper end of the hole 186 is covered by a pressure sensor assembly 187. The assembly 187 includes a diaphragm 191 (Fig. 16), a diaphragm clamp 192, a pressure sensor 193, and a sensor cup 194 which is shown in detail in Figs. 21-26. The diaphragm 191 may be generally similar to the diaphragm 58 shown in Fig. 4 and includes a circular central portion surrounded by an annular seal portion. The clamp 192 is annular, having a central hole 195 therein which receives the central portion of the diaphragm 191 (for example, see Fig. 11). The clamp engages and presses the annular seal portion of the diaphragm 191 into sealing engagement with the upper surface of the plate 161 around the hole 186. With reference to Figs. 21 to 26, the sensor cup 194 is generally similar to the cup 66 and includes an interior cavity 196 that receives the pressure sensor 193. The bottom side of the cavity 196 is open and fits over the hole 186, with the central portion of the diaphragm 191 and the sensor 193 extending into the cavity 196. Below and around the cavity 196 is formed an annular groove 197 which receives the clamp 192 and the outer seal portion of the diaphragm and holds them in place. The cup 194 thus presses the clamp 192 and the seal portion of the diaphragm 191 downwardly so that the seal portion forms a liquid tight seal with the upper surface of the plate 161. The flexible center portion of the diaphragm engages the underside of the sensor 193, so that the pressure of the liquid in the hole 186 and on the underside of the center portion of the diaphragm presses the center portion upwardly against the sensor 193 which generates an electrical signal representative of the pressure. Two locator pins 198 extend downwardly from the underside of the cup 194 and into two blind holes 199 in the plate 161 on opposite sides of the hole 186, in order to locate the sensor assembly 187 over the hole 186. With reference to Figs. 21, 22 and 24, a thin shaving or groove 200 is formed in the bottom surface of the cup 194 on its side which is adjacent the switches 184. The groove 200 provides clearance for a thin strip of insulation under the switches 184. Figs. 17, 18 and 19 illustrate a component clamp and potting guard structure 205 of the apparatus. The structure 205 includes a generally rectangular outer frame 206 having a larger dimension than the outer periphery of the cold plate 161, so that the frame 206 may extend around the plate 161 and rest on the upper surface of a circuit board 203 as shown in Figs. 18 and 19. As shown in Fig. 16, the flat circuit board 203 has a rectangular opening 203A formed in it; the opening 203A has slightly larger dimensions than the cold plate 161 but slightly smaller dimensions than the frame 206. A gasket or seal 203B is positioned between the board 203 and the upper surface of the bottom 151A. A small groove 207 is formed in the bottom edge of the frame 206 so that a bead 208 of glue or sealant in the groove 207 forms a seal between the circuit board 203 and the underside of the frame 206. A clamp 209 of the structure 205 extends across the upper surface of the plate 161 between two side walls of the frame 206, as best shown in Figs. 17 and 18. The frame 206 and the clamp 209 are preferably integrally molded of a plastic material such as 20% glass filled polypropylene or nylon. The function of the clamp 209 is to hold the six switches 184 of the inverter tightly against the plate 161. However, the previously mentioned thin strip of insulation (not shown, which extends into the groove 200 of the part 194) is clamped in between the switches 184 and the plate 161. As best shown in Fig. 18, three pairs of the switches 184 are positioned in a row on the plate 161, and the clamp 209 presses the switches toward the plate 161. The clamp 209 is formed by three clamp portions 210A, 210B and 210C which are joined together in a row, and the endmost clamp portions 210A and 210C are joined to the frame 206. Each of the clamp portions is vertically and horizontally enlarged and has two recesses 211 formed therein, each of the recesses receiving one of the switches 188 as shown in Fig. 18. At each end of each of the clamp portions 210A, 210B and 210C is formed a hole which receives a screw 213 for tightly securing the clamp 209 to the cold plate 161. The inside upper surface of each of the recesses 211 includes a downwardly extending protrusion 215 which engages a switch 184. Each pair of the recesses 211 is between two of the screw fasteners 213, and, when the screws 213 are tightened, the strip portions 210A, 210B and 210C of the clamp 209 between adjacent screws 213 are pressed down. While the portions of the clamp between two screws may bow or arch, the protrusions 215 engage the center areas of the switches and press the switches squarely and tightly against the plate 161. The clamp 209 has an increased height over the recesses, and an increased width, as indicated at 214 (Figs. 17 and 19) adjacent the screws 213, to strengthen the clamp. Between the recesses 211 of each pair, the clamp 209 includes downwardly projecting and outwardly extending parts 210 (Figs. 18 and 20) which separate the switches 184 and also strengthen the clamp. With reference to Fig. 19, after the switches 184, the clamp 209, the rectifier 181, and the pressure sensor assembly 187 are secured in place on the plate 161 within the frame 206, the upper surface of the plate, around the above components and within the frame 206, is covered by a heat and electrical insulating material 216. In the present instance, the material 216 comprises a conventional potting compound which is poured on the plate 161 in liquid form and then sets or hardens. As shown in Figs. 18 and 19, the material 216 covers the top and the edges of the cold plate 161, and it flows laterally out to the boundary formed by the frame 206, the seal 203B and the circuit board 203. The insulating material 216 performs a number of functions. First a portion of the underside of the plate 161 is in contact with the liquid in the flow carrier 150. In a situation where the liquid is quite cold relative to the ambient air, and where the humidity is quite high, condensation would likely form on the upper surface of the cold plate 161 if it were not covered by the heat insulating material 216. Any condensation might collect around the electrical components and damage them, but the material 216 prevents such damage. Second, the amount of the material 216 is sufficient to cover the lower sides of the clamp 209, the edge portions 214 plus the downward projecting and outward extending parts 210 of the clamp and to completely cover the plate 161. It flows around and surrounds the components on the plate 161 and provides additional security to keep the components in place. Third, the clamp 209 and the sensor cup 194 are made of a heat and electrical insulating plastic such as polypropylene or nylon and they are tightly secured to the plate 161 by screws. Such materials tend over time to creep or flow away from high pressure areas such as the portions surrounding the fastening screws, causing the initial compression produced by the screws to be lost. This tendency to creep can be counteracted by the material 216 which is rigid once it sets and prevents the edge portions of the clamp 209 and the sensor cup 194 from moving. With reference to Fig. 16, holes 220 may be formed through the side walls of the box 151 for electrical cables, and removable plugs 221 may be provided for the holes. Wiring leading to and between the electrical components are not illustrated in the drawings, but conventional wiring techniques may be employed. Additional electrical components (not illustrated) which do not generate significant amounts of heat may be mounted on the circuit board 203 within the container 151. It will be apparent from the foregoing that novel and useful apparatus is described and illustrated. The apparatus forms a compact package or module for sensing the pressure of liquid being pumped and for cooling heat generating components of a control system. The control system is operable to control a motor-pump unit which moves the liquid through the apparatus, whereby the liquid being pumped is utilized to cool the control system. The pressure sensor is directly responsive to the liquid pressure and the components to be cooled are directly mounted on a heat sink which also supports the pressure sensor. Further, the flow carrier is shaped to accelerate the liquid flow across the heat sink for liquid cooling of the heat sink and the components. The pressure sensor includes an improved diaphragm having an O-ring integrally molded on its outer periphery, for forming a seal around the diaphragm. Means is also provided to prevent potentially harmful condensation from forming on the cold plate.

Claims: Liquid flow apparatus comprising: a) a pump (11) for the liquid; b) an electric motor (12) connected to drive said pump; c) pipework (16, 23) connected to said pump and operable to carry the pumped liquid to liquid utilization apparatus; and d) a control module (21 or 151) for controlling said motor, said module comprising a flow carrier (31 or 101 or 150) including a conduit (32 or 102) connected in said pipework and operable to carry the liquid, said conduit having an opening (112 or 154) in a side thereof, characterised in that said module further comprises: 1) a heat sink (51 or 113 or 161) on said conduit and over said opening, said heat sink having a wet side exposed to the liquid and a dry side sealed from the liquid; and 2) at least one heat generating component (73, 74 or 117 or 152 or 181, 184) mounted on said heat sink and cooled by said heat sink and the liquid. Liquid flow apparatus according to Claim 1, further including heat and electrical insulating material (216) on said dry side of said heat sink (161), said material extending around the periphery of the heat generating component or components (181, 184). Liquid flow apparatus according to Claim 1 or 2, further including clamp means (209) extending across said dry side, said clamp means pressing the or each heat generating component (181, 184) against said dry side for securing the or each heat generating component to said heat sink (161). Liquid flow apparatus according to Claim 2 or Claim 3 as dependent on Claim 2, wherein said dry side of said heat sink (161) has an outer periphery, the apparatus including a frame (206) extending adjacent said outer periphery of said dry side and said insulating material (216) extending to said frame and around the heat generating component or components (181, 184). Liquid flow apparatus according to Claim 4 as dependent on Claim 3, wherein a potting compound (216) covers the edge and lowerportions of said clamp means (209). Liquid flow apparatus according to Claim 3 or Claim 4 as dependent on Claim 3 or Claim 5, wherein said clamp means (209) comprises a strip which extends over the or each heat generating component (181,184) and fasteners (213) on opposite sides of the or each component for securing said strip to said heat sink (161), said strip including a protrusion (215) adjacent the or each component for engaging and applying pressure on the component. Liquid flow apparatus according to any preceding claim, wherein the size of said opening is in the range from 1.5 to 5.0 times the size of said conduit (32). Liquid flow apparatus according to any preceding claim, wherein said conduit (32) includes an enlarged portion (36) and said opening is formed across said portion. Liquid flow apparatus according to Claim 8, wherein said enlarged portion (36) includes rib means (81a - 81f) for accelerating the flow of liquid past said heat sink (51). Liquid flow apparatus according to any preceding claim, wherein said flow carrier (31) is made of plastic and said heat sink (51) is made of a high heat conductive material. Liquid flow apparatus according to any preceding claim, wherein said control module (21) further includes a housing (43) on said flow carrier (31), said housing enclosing said heat sink (51) and the or each heat generating component (73, 74). Liquid flow apparatus according to any preceding claim, further including seal means (53) between said heat sink (51) and said conduit (31) for sealing said dry side from said wet side. Liquid flow apparatus according to Claim 8 or any of Claims 10 to 12 as dependent on Claim 8, wherein said conduit (32) includes two ends (33) by which it is connected in said pipework (16, 23), said enlarged portion (36) and said opening being between said two ends and said conduit further including a substantially rectangular section between each of said ends and said enlarged portions. Liquid flow apparatus according to Claim 13, wherein each of said substantially rectangular sections has a flat side which is substantially coplanar with said opening of said enlarged portion (36). Liquid flow apparatus according to Claim 13 or 14, wherein said ends (33) of said conduit (32) are enlarged for connection in said pipework (16, 23). Liquid flow apparatus according to Claim 15, wherein said enlarged ends (33) are threaded for connection in said pipework (16, 23). Liquid flow apparatus according to any preceding claim, wherein said heat sink (51) has an opening (56) therethrough from said wet side to said dry side, the apparatus further including a flexible diaphragm (58) covering said opening and a sensor (57) mounted on said dry side and engaging said diaphragm. Liquid flow apparatus according to Claim 17, wherein said sensor (57) comprises a pressure sensor. Liquid flow apparatus according to Claim 17 or 18, wherein said diaphragm (58) includes seal means (59) on an outer periphery thereof. Liquid flow apparatus according to Claim 19, wherein said seal means (59) comprises an O-ring formed integrally with said diaphragm (58). Liquid flow apparatus according to Claim 19 or 20, further comprising a seal clamp (61) encircling said diaphragm (58) and compressing said seal means (59) against said heat sink (51) to form a seal between said heat sink and said diaphragm. Liquid flow apparatus according to Claim 21 as dependent on Claim 20, wherein an annular groove (62) is formed in said seal clamp (61) and/or said heat sink (51), said O-ring (59) being located and pressed in said groove. Liquid flow apparatus according to Claim 22, further comprising a sensor cup (66) positioned over said diaphragm (58) and said seal clamp (61) and secured to said heat sink (51), said sensor (57) being mounted within said sensor cup. Apparatus for monitoring pressure in pipework (16, 23), comprising a liquid flow carrier (150) having inlet and outlet ends (167) connectable with said pipework, an opening (154) formed in said carrier between said ends, a plate (161) fastened to said carrier over said opening and pressure sensing means (187), characterised in that said pressure sensing means has electronic circuitry, said pressure sensing means being mounted on said plate and exposed to pressure in said flow carrier, the apparatus further including seal means (159) between said flow carrier, said plate and said pressure sensing means. Apparatus according to Claim 24, wherein said plate (161) has an aperture (186) formed therein and said pressure sensing means (187) comprises a diaphragm(191) covering said aperture and a pressure sensor (193) engaging said diaphragm. Apparatus according to Claim 24 or 25, further comprising pump means (11) for producing liquid flow in said pipework (16, 23) and in said carrier (150), said pressure sensing means (187) being operable to control said pump means. Liquid flow apparatus including an electric motor (12) for driving a pump (11), pipework (16, 23) connected to the pump for conveying the liquid to liquid utilization means and a module (21 or 151) for controlling the motor, said module comprising a conduit (32 or 102) connected in said pipework and forming a flow passage operable to carry the liquid in said pipework, characterised in that the apparatus further includes a heat sink (51 or 113 or 161) on said conduit, said heat sink having one side exposed to said flow passage, and heat generating control components (73, 74 or 117 or 152 or 181, 184) mounted on said heat sink, said control components being operable to control the pressure of the liquid in said conduit. Liquid flow apparatus according to Claim 27, wherein said control components (73, 74 or 152 or 117 or 181, 184) are operable to control the speed of the motor (12). Liquid flow apparatus according to Claim 27 or 28, wherein said module (151) further includes pressure sensing means (187) mounted on said heat sink (161) and exposed to said flow passage, said control components (181, 184) being connected to said pressure sensing means and being operable to control the motor (12) to maintain a selected liquid pressure range. Liquid flow apparatus according to Claim 29, wherein said heat sink (161) has an opening (186) therein, said pressure sensing means (187) including a diaphragm (191) over said opening and exposed to said flow passage, the apparatus further including means (193) engaging said diaphragm for providing a signal representing the liquid pressure on said diaphragm. A control module for controlling the speed of an electric motor (12) of a liquid flow apparatus, the module comprising a plate (161) made of a high efficiency heat conducting material, a plurality of electrical components (181, 184) mounted on one side of said plate, said components generating heat during operation of said module, flow means (150) for moving the pumped liquid across the opposite side of said plate to cool it and a heat insulating layer (216) on said one side of said plate and extending around said components, said layer being operable to secure said components to said plate and to prevent condensation from occurring on said one side of said plate. A control module according to Claim 31, further including a pressure sensor (193) mounted on said one side of said plate for sensing the pressure of said cooling liquid, said layer (216) extending around said pressure sensor. A control module according to Claim 31 or 32, wherein said heat insulating layer (216) comprises a potting compound. A control module according to any of Claims 31 to 33, wherein said electrical components comprise a rectifier (181) and a plurality of solid state switches (184), said switches being positioned in a row on said one side of said plate (161), each of said switches including a bottom side which is adjacent said plate and a top side which is opposite said bottom side, the module further including a clamp (209) for securing said switches to said plate, said clamp comprising a strip which extends across said top sides of said switches and a plurality of fasteners (213) between said switches for securing said strip to said plate and for pressing said strip against said switches. A control module according to Claim 34, further including a frame (206) around the periphery of said plate (161), said clamp having its ends secured to said frame, a potting compound (216) being within said frame and extending over the edge and lower portions of said clamp.

Inventors: COCHIMIN JIMMY, HALSEY RICHARD J, COCHIMIN, JIMMY, HALSEY, RICHARD J.
Applicants: FRANKLIN ELECTRIC CO INC, FRANKLIN ELECTRIC CO., INC.
Application year: 1995
Main classification: F04D15
IPC codes: F04B47, F04B49, G05D16, F04D15