Patent Publication Number: US-2002011524-A1

Title: Fluid heating methods and devices

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  8   a,  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  8   a  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° 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  8   a  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  8   a,  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  11   a  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  21   a  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˜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˜0.36, (Q/Qmax) is greater than or equal to 0.92. Furthermore, when (W/L) is set within the range of 0.1˜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˜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 ⅛ (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