Fluid heating methods and devices

Abstract

A heating pump 10 includes a rotor 20 having a plurality of blades 21. A dividing wall 15 radially extends within an interior portion of the heating pump 10. The dividing wall 15 has a width W. A distance L is defined along a circular arc between adjacent blades 21 in an intermediate position 21a along the radial direction of the blades 21. A ratio W/L is preferably about 0.07 to 0.36, more preferably about 0.11 to 0.30 and most preferably, about 0.20.

Description

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to turbine-type pump, which can be utilized as fluid heating devices. The present invention also relates to methods for heating fluids.

[0003] 2. Description of the Related Art

[0004] A known turbine or regenerative pump that is utilized as a fluid heating device is disclosed in U.S. Pat. No. 3,720,372. The fluid heating device includes a fluid regulating means connected to the outlet of a pressurizing pump 110. The fluid temperature is raised (heated) by means of the fluid regulating means. As shown in FIG. 5, the pump 110 includes a rotor (impeller) 120 that rotates within housing 111 in the direction of arrow 130. The rotor 120 has a plurality of radially extending walls (blades) 121 that are disposed on both side surfaces (peripheral surfaces) and radially extend from rotational axis 122. The rotor 120 also includes channels 123 that are disposed between the blades 121. A dividing wall 115 divides the interior of the housing 111 between a suction port 113 and a discharge port 114. When the rotor 120 rotates, fluid is drawn into the pump 110 via section port 113 and the fluid pressure increases due to the flow of fluid within the channels 123 that are disposed between the blades 121. By increasing the number of impacts of the channels 123 on the fluid, the fluid pressure increases. The pressurized fluid is then discharged through the discharge port 114. A regulating valve (not shown) is disposed downstream of the discharge port 114 and the regulating valve regulates the fluid pressure generated by the pump 110. By restricting the flow of pressurized fluid discharged from the discharge port 114, a portion of the work of the pump 110 is converted into an increase in the internal energy of the fluid, and the temperature of the fluid increases. Thus, by increasing the number of impacts of the channels 123 on the fluid, the fluid can be heated more rapidly. However, the discharge flow rate will naturally be decreased when the regulating valve restricts the flow of pressurized fluid.

SUMMARY OF THE INVENTION

[0005] It is, accordingly, one object of the present invention to teach improved turbine-type pumps that can be utilized as fluid heating devices.

[0006] In one embodiment of the present teachings, fluid heating devices (pumps) may include a suction port and a discharge port separated by a dividing wall disposed within a housing. A rotor or impeller is rotatably disposed within the housing and preferably comprises a plurality of blades or impeller vanes (i.e. radially extending walls) on both side surfaces. The dividing wall preferably prevents the direct flow of fluid from the suction port to the discharge port when a blade is aligned with the dividing wall. A fluid regulator optionally communicates with the discharge port. When the fluid heating device operates, the fluid regulator regulates the fluid pressure and restricts the flow of pressurized fluid discharged from the fluid heating device. As a result, the internal energy of the fluid increases and thus the fluid temperature also increases.

[0007] In a preferred aspect of the present teachings, the width (W) of the dividing wall and the distance (L) between the rotor blades (radially extending walls) can be adjusted in order to efficiently heat the fluid. For example, the ratio (W/L) preferably falls within the range of about 0.07-0.36. More preferably, the ratio (W/L) falls within the range of about 0.11-0.30 and most preferably, the ratio is about 0.20. The fluid may be a coolant, such as cooling water, lubricating oil, or other similar liquid substances, and/or a hydraulic fluid. In fact, any type of fluid that is capable of conducting heat can be utilized with the present teachings. Further, the "width of the dividing wall" is preferably defined as the thinnest width of the dividing wall, if the width of the dividing wall is not uniform.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 shows a schematic view of a representative coolant circulation circuit utilized in an automobile air conditioning system.

[0009] FIG. 2 is a cross-sectional view of a representative heating pump (fluid heating device).

[0010] FIG. 3 is a sectional view taken along the line III-III shown in FIG. 3.

[0011] FIG. 4 is a graph illustrating the correlation between (Q/Qmax) and (W/L).

[0012] FIG. 5 is a cross-sectional view of a known heating pump.

DETAILED DESCRIPTION OF THE INVENTION

[0013] Representative fluid heating devices preferably provide a ratio (W/L) of the dividing wall width (W) to the distance (L) between impeller or rotor blades along a circular arc that is about 0.07 to 0.36. More preferably, the ratio is about 0.11 to 0.30 and most preferably, the ratio is about 0.20.

[0014] Representative fluid heating devices may include, for example, a housing defining a suction port and a discharge port. A dividing wall is preferably disposed within an interior portion of the housing between the suction port and the discharge port and has a prescribed width (W). A rotor or impeller may be rotatably disposed within the housing and may include a plurality of blades (impeller vanes) or radially extending walls that are disposed on the peripheral surface of the rotor. Optionally, a regulator may be disposed in a manner to communicate with the pressurized fluid discharged from the discharge port.

[0015] Representative methods for heating a fluid may be performed, for example, utilizing the representative fluid heating devices, although naturally other fluid heating devices also may be utilized. For example, representative methods for heating a fluid may include rotating a rotor or impeller with respect to a fluid. The rotor may include blades or radially extending walls that are separated along a circular arc by a distance L. The blades may pass by a dividing wall having a width W and preferably the ratio (W/L) is about 0.07 to 0.36. The pressure of the fluid is increased by the work of the rotor and a fluid pressure regulator may regulate the fluid. For example, the pressure regulator may restrict the flow of the pressurized fluid exiting from the rotor. Consequently, the fluid temperature may be increased.

[0016] In more preferred methods, the ratio (W/L) may be about 0.11 to 0.30 and most preferably the ratio (W/L) is about 0.20.

[0017] Additional representative examples of the present teachings will be described in further detail with reference to the attached drawings. This detailed description is merely intended to teach a person of skill in the art further details for practicing preferred aspects of the present teachings and is not intended to limit the scope of the invention. Only the claims define the scope of the claimed invention. Therefore, combinations of features and steps disclosed in the above detail description may not be necessary to practice the invention in the broadest sense, and are instead taught merely to particularly describe some representative examples of the invention. In addition, the present teachings naturally may be combined in ways that are not specifically enumerated in order to provide additional useful embodiments of the present teachings.

[0018] As shown in FIG. 1, an automobile engine E may include a water pump 52 that supplies a coolant (e.g. engine coolant) to a water jacket 50. The coolant is preferably antifreeze, e.g. a mixture of water and ethylene glycol, although naturally other fluids may be utilized with the present teachings. A coolant circulating circuit may include the engine E, a radiator 6, a thermostat valve 7, a heater core 8, an electromagnetic valve 8a, a check valve 9, a fluid heating device H, and a plurality of pipes 1-5 connecting the respective parts. In this embodiment, three pipes 1, 2, 3 are located downstream of water jacket 50 and two pipes 4, 5 are located upstream of the water jacket 50. Pipe 4 defines a return path to the water pump 52 via the radiator 6 and the thermostat valve 7. Pipe 5 defines a return path to the water pump 52 via the electromagnetic valve 8a and the heater core 8. Pipe 1 define a path from the water jacket 50 to the thermostat valve 7, which is disposed at the branch point of pipe 1 and pipe 4. Pipe 2 defines a path connecting the water jacket 50 to both pipes 4, 5 via the check valve 9. Pipes 2 and 3 are disposed in a parallel relationship between the water jacket 50 and pipes 4, 5.

[0019] The water pump 52 is linked to a crankshaft (output shaft) of the engine E via a V-belt or other energy transmitting means and is driven by the engine E. The water pump 52 is disposed in the vicinity of the inlet opening of the water jacket 50 and increases the pressure of the coolant that has returned via pipes 1, 4, 5 into the water jacket 50. The coolant moves through the circulating circuit as a result of the pressure applied by the water pump 52.

[0020] The radiator 6 functions as a heat exchanger in order to radiate heat from the coolant to the outside air. The thermostat valve 7 detects the temperature of the coolant flowing from the engine E via pipes 1 or 4 and connects either pipe 1 or pipe 4 to the water pump 52 according to the detected temperature. If the coolant temperature detected by the thermostat valve 7 is lower than a pre-selected temperature (for example, 80.degree. C.), pipe 1 is connected to the water pump 52. Therefore, the coolant circulating circuit is shortened and the waste heat from the engine will increase the coolant temperature. On the other hand, if the coolant temperature detected by the thermostat valve 7 is higher than the pre-selected temperature, pipe 4 is connected to the water pump 52. Therefore, coolant circulation via pipe 1 is stopped and the coolant temperature decreases by passing through radiator 6. Thus, the radiator 6, the thermostat 7, the pipe 4, and other circuit elements and other pipes are utilized in order to selectively cool the coolant.

[0021] The heater core 8 functions as a heat exchanger and warms up the air inside the vehicle cabin by using the heat from the coolant supplied through pipe 5. The electromagnetic valve 8a is an ON/OFF valve (open/close valve) that controls the supply of coolant from the engine E to the heater core 8 according to the cooling/warming condition of the automobile air conditioning system. A representative heating circuit may include the heater core 8, the electromagnetic valve 8a, pipe 5, and other circuit elements and other pipes.

[0022] The check valve 9 permits unidirectional flow of coolant from the water jacket 50 to pipes 4 and 5, but does not permit the coolant to flow in the opposite direction. If the flow of coolant via pipe 1 is blocked by the thermostat valve 7 (i.e., the radiator is operating), the check valve 9 is opened and maintains a constant flow of coolant to pipe 4 and/or pipe 5.

[0023] As shown in FIG. 1, the turbine-type or regenerative pump (fluid heating device) H includes a heating pump 10 disposed in series with pipe 3 and a regulating valve 40, which may be a fluid regulating means. The heating pump 10 and the regulating valve 40 cooperatively operate so that both pumping and heating functions are provided at the same time (or selectively), while maintaining a balance of both functions.

[0024] As shown in FIGS. 2 and 3, the heating pump 10 preferably includes a rotor (impeller) 20 rotatably disposed within housing 11. The housing 11 defines a suction port 13 that is adapted to draw the coolant into the housing 11 and a discharge port 14 that is adapted to discharge coolant from the housing 11. A dividing wall 15 separates the suction port 13 from the discharge port 14. Preferably, the dividing wall 15 has a uniform, or substantially uniform, width (W) with respect to the rotor 20. Further, the dividing wall 15 preferably prevents the direct flow of coolant between the suction port 13 and the discharge port 14. Instead, as shown in FIG. 2, the coolant will move counterclockwise within the substantially cylindrical chamber 25 from the suction port 13 to the discharge port 14. The chamber 25 is connected to (communicates with) the upstream of pipe 3 via the suction port 13 and is connected to (communicates with) the downstream (or the regulating valve 40) of pipe 3 via the discharge port 14. The rotor 20 preferably includes an integrally formed drive shaft 22 and both are rotatably disposed inside the chamber 25. A pulley 16 is fixedly mounted on the end of the drive shaft 22 outside the housing 11. The pulley 16 is operationally linked to the crankshaft (output shaft) of engine E via a V-belt (see FIG. 1) or other energy transmitting means.

[0025] The rotor 20 preferably has a disk-like shape and includes a plurality of blades (radially extending walls) 21 that are equidistantly disposed on both side surfaces (peripheral surfaces) of the rotor body 24. For example, fourteen (14) blades 21 may be utilized. The blades 21 may be substantially rectangular-shaped pieces having a length t in the radial direction and the blades 21 may radially extend from the rotational axis of the rotor body 24. Concave channels 23 are formed between the blades 21, which channels 23 are substantially semi-circular in cross-section. The channels 23 also may be, for example, depressions or recesses. If blades 21 are disposed on both sides of the rotor body 24, the total number of blades 21 can be reduced.

[0026] When the drive shaft 22 and the rotor 20 of the heating pump 10 rotate due to the driving force of engine E, the coolant is drawn through the suction port 13, flows inside the chamber 25 and is discharged from the discharge port 14. Because the rotor 20 rotates, an eddy flow (secondary vortex) as shown by the arrows in FIG. 3 is generated in the area formed by a channel 11a having a semicircle cross section in the housing 11 that is opposite the rotor 20 and channels 23 of the rotor 20. The coolant pressure gradually increases by repeatedly joining or converging the eddy flow generated within the channels 23 and the main flow inside the chamber 25. The heating pump 10 thus provides a fluid transport function that is similar to the water pump 52 and can be used as an auxiliary pump to support the water pump 52.

[0027] When the dividing wall 15 is aligned with a channel 23 during operation of the heating pump 10, a space S is defined between the inner surface of the dividing wall 15 and the surface of the channel 23, as shown in FIG. 3. The moving blades 21 act on the coolant to cause a complete revolution of the coolant. The coolant is then diverted to the discharge port 14 by the dividing wall 15. As a result of this action, the heating pump 10 increases the coolant pressure. As a result of the space S, the coolant can leak directly from the relatively high-pressure discharge port 14 to the relatively low-pressure suction port 13 via the space S when the dividing wall 15 is aligned with a channel 23.

[0028] As noted above, the heating pump 10 also provides a fluid heating function in addition to the fluid transport function. As shown in FIG. 2, a small gap G is defined between the peripheral edge of the rotor 20 and the inner surface of the chamber 25. Pressurized fluid flows along this gap G from the suction port 13 to the discharge port 14. When the rotor 20 rotates, the energy of the pump 10 acts on the coolant in the chamber 25 and the coolant temperature increases due to the increased the internal energy of the coolant. Therefore, the force applied to the drive shaft 22 and the rotor 20 via the pulley 16 is converted into both pressurizing work of the rotor 20 and the heat generated as a result of the power loss.

[0029] The regulating valve 40 can restrict the flow of the coolant from the discharge port 14. The regulating valve provides a braking force that acts on the pressurized coolant supplied by the rotor 20 and thereby increases the coolant temperature. Therefore, the heating pump 10 can heat the coolant.

[0030] Since the fluid transport function and the fluid heating function are contrary to each other, the coolant can be heated to a higher temperature if regulating valve 40 greatly restricts the flow of coolant from the discharge port 14. However, in this case, the amount of coolant that is discharged from the discharge port 14 is decreased. On the other hand, if the regulating valve 40 is adjusted to permit a greater amount of coolant to discharge from the discharge port 14, more coolant naturally can be discharged. However, in this case, the coolant temperature increases less.

[0031] The present inventors have determined that the heat generated by heating pump 10 is influenced by the nature of the internal leak of the coolant from the discharge port 14 to the suction port 13 via the space S between the dividing wall 15 and channels 23 of the rotor 20. In particular, a correlation exists between the ratio (W/L) of the width (W) of the dividing wall 15 to the circular arc length (L) between the blades 21 in the intermediate position 21a along the radial direction of the blades 21, as shown in FIG. 2. As shown in FIG. 4, the amount of heat (Q) generated as the cooling fluid temperature is raised is influenced by the ratio (W/L). In FIG. 4, "Qmax" represents the maximum amount of heat generated by the pump 10. Thus, the ratio (Q/Qmax) represents a ratio of the amount of heat generated at each measurement point of W/L in relation to Qmax.

[0032] As shown in FIG. 4, when (W/L) is set within the range of 0.about.1, the amount of heat generated by the coolant reaches a maximum (Qmax) at (W/L)=0.20. Thus, (Q/Qmax) is 1 when (W/L) is 0.20. When (W/L) is increased or decreased with respect to this reference point, the value (Q/Qmax) decreases. However, when (W/L) is set within the range of 0.07.about.0.36, (Q/Qmax) is greater than or equal to 0.92. Furthermore, when (W/L) is set within the range of 0.1.about.0.30, (Q/Qmax) is greater than or equal to 0.95.

[0033] To the contrary, the inventors have determined that the ratio (W/L) of the pump disclosed in U.S. Pat. No. 3,720,372, which is shown in FIG. 5 is about 0.41. Thus, the present teachings provide heating pumps that are capable of more efficiently generating heat.

[0034] Naturally, the above-described embodiments may be modified in various ways without departing from the scope of the present invention. For example, the ratio (W/L) according to the above embodiment can be set to various values within the range of 0.07.about.0.36. Further, although the blades 21 have been described as being disposed on both side surfaces of the rotor body 24, the blades 21 can also be disposed only on one side surface of the rotor body 24. In addition, although a coolant comprising water and ethylene glycol was utilized in the representative embodiment, various other fluids that are capable of conducting heat can be used instead of this coolant.

[0035] Preferably, each blade may be made of steel and may be inserted to the rotor body. Each blade may preferably have a thickness of 1.2 mm or less than 1.2 mm. Relatively thin blade can increase the space defined by the mutually neighboring blades and thus, contributing the effective heat generation, while the steel blade can increase the strength of the blade.

[0036] With respect to the structure of the actuation chamber, a fluid introducing passage may preferably connect the high-pressure area (discharge area) to the low-pressure area (suction area). Preferably, the fluid introducing passage may be formed within the dividing wall. Further, a fluid release valve that opens and closes the fluid introducing passage may be adapted in order to release the high-pressure fluid to the low-pressure area. By releasing the high-pressure fluid to the low-pressure area, excessive heat generation can be alleviated. For example, a rotary valve, a ball valve or a lead valve can be utilized for the release valve. Further, a pilot valve for opening the release valve may be installed. The pilot valve may open the release valve with relatively small amount of the fluid and thus, the alleviation control of the heat generation can quickly and precisely be performed. Preferably, the pilot valve may include a spool that can actuate the release valve.

[0037] Further, each groove of the pump housing may include a plurality of shield blades at the inner circumferential side that corresponds to the rotor body (inner circumferential side just close to the drive shaft). The height of the shield blade measured from the inner circumferential surface of the groove in the direction of the outer circumferential surface of the groove may be approximately 1/8 (one eighth) of the height of the actuation chamber measured from the inner circumferential surface of the groove to the outer circumferential surface of the groove. By such structure, heat generating effect can be effectively controlled.

[0038] The thickness of the dividing wall in the rotational direction of the rotor can be selected from the various dimensions in relation to the width of the space defined by the mutually neighboring blades with respect to the rotational direction of the rotor. On the other hand, in order to secure the heat generating efficiency and to reduce the noise in operating the fluid heating device, the thickness of the dividing wall in the rotational direction of the rotor may preferably be equal to or wider than the width of the space defined by the mutually neighboring blades with respect to the rotational direction of the rotor. Further, the dividing wall may have groove. Preferably, multiple grooves may be provided on the surface of the dividing wall that faces the rotor blade.

[0039] Further techniques for making and using fluid heating devices are taught in a U.S. patent application Ser. No. 09/576,355, a U.S. patent application filed on even date herewith entitled "Fluid Heating Devices" naming Takahiro Moroi, Masami Niwa and Shigeru Suzuki as inventors and claiming Paris Convention priority to Japanese patent application serial number 2000-216412 and a U.S. patent application filed on even date herewith entitled "Fluid Heating Devices" naming Takahiro Moroi, Masami Niwa and Shigeru Suzuki as inventors and claiming Paris Convention priority to Japanese patent application serial number 2000-214602, all of which are commonly assigned and are incorporated by reference as if fully set forth herein

Claims

1. A fluid heating apparatus comprising: a housing defining an interior, a suction port and a discharge port, a rotor rotatably disposed within the housing interior, the rotor comprising a plurality of radially extending blades disposed on the peripheral surface of the rotor and a plurality of channels disposed between the plurality of blades, wherein the respective blades are each separated by a distance L that is defined as a circular arc length between adjacent blades taken at intermediate position along the radial direction of the blades and a dividing wall radially disposed along the housing interior between the suction port and the discharge port and having a width W, the dividing wall preventing a direct flow of fluid between the suction port and the discharge port when a rotor blade is aligned with the dividing wall, wherein the ratio W/L is within a range of about 0.07 to 0.36.

2. A fluid heating apparatus as in claim 1, wherein the ratio W/L is within a range of about 0.11 to 0.30.

3. A fluid heating apparatus as in claim 1, wherein the ratio W/L is about 0.20.

4. A fluid heating apparatus as in claim 1, further comprising a fluid regulator in communication with the discharge port, wherein the fluid regulator is arranged and constructed to restrict a flow of fluid exiting from the discharge port.

5. A fluid heating apparatus as in claim 1, wherein the channels have a substantially semi-circular cross-section.

6. A fluid heating apparatus as in claim 1, further comprising an engine supplying rotational power to the rotor and a heating system, wherein fluid discharged from the discharge port is utilized to heat the heating system.

7. A fluid heating apparatus as in claim 6, further comprising a fluid regulator in communication with the discharge port, wherein the fluid regulator is arranged and constructed to restrict a flow of fluid exiting from the discharge port, the channels have a substantially semi-circular cross-section and the ratio W/L is within a range of about 0.11 to 0.30.

8. A fluid heating apparatus as in claim 7, wherein the ratio W/L is about 0.20.

9. A regenerative pump comprising: a housing defining an interior, a suction port and a discharge port, an impeller rotatably disposed within the housing interior, the impeller comprising a plurality of radially extending impeller vanes disposed on the peripheral surface of the impeller and a depressions formed between each two adjacent impeller vanes, wherein the impeller vanes are separated by a distance L and the distance L is defined as a circular arc length between adjacent impeller vanes taken at a middle position of the impeller vane along the radial direction of the impeller vane and a dividing wall disposed along the housing interior between the suction port and the discharge port and having a width W, the dividing wall preventing a direct flow of fluid between the suction port and the discharge port when one impeller vane is aligned with the dividing wall, wherein the ratio W/L is within a range of 0.07 to 0.36.

10. A regenerative pump as in claim 9, wherein the ratio W/L is within a range of 0.11 to 0.30.

11. A regenerative pump as in claim 9, wherein the ratio W/L is 0.20.

12. A method of heating a fluid comprising: rotating an impeller of a regenerative pump in order to draw the fluid into the regenerative pump, the impeller comprising a plurality of radially extending impeller vanes disposed on the peripheral surface of the impeller, wherein the impeller vanes are separated by a distance L and the distance L is defined as a circular arc length between adjacent impeller vanes taken at a middle position of the impeller vane along the radial direction of the impeller vane and wherein a dividing wall of the regenerative pump has a width W and a ratio W/L is within a range of 0.07 to 0.36; and regulating fluid pressure within the regenerative pump in order to restrict a flow of pressurized fluid from the regenerative pump, whereby the fluid is heated.

13. A method as in claim 12, wherein the ratio W/L is within a range of 0.11 to 0.30.

14. A method as in claim 12, wherein the ratio W/L is 0.20.