Switching of a pump based on the throughput determined by a thermal flow meter

Abstract

A feed pump to increase the pressure in a line includes a pumping chamber for a pumping medium. At least one temperature sensor, which is arranged in the feed pump, is allocated to the pumping chamber and is in thermal contact with the pumping chamber for determining a temperature of the pumping medium in the pumping chamber. A temperature control device is allocated to the at least one temperature sensor and by which defined temperature conditions can be created in an area surrounding the at least one temperature sensor. An evaluation device to which the at least one temperature sensor is coupled for signal purposes uses the data from the at least one temperature sensor to determine whether pumping medium is flowing through the pumping chamber or not.

Claims

1. A method for operating a feed pump for increasing pressure in a line to which the feed pump is connected, the method comprising: providing a feed pump comprising: a pumping chamber for a pumping medium, at least one temperature sensor for detecting a temperature of pumping medium in the pumping chamber, the at least one temperature sensor arranged in the feed pump, allocated to the pumping chamber, and in thermal contact with the pumping chamber, a temperature control device allocated to the at least one temperature sensor and by which defined temperature conditions can be created in an area surrounding the at least one temperature sensor, and an evaluation device to which the at least one temperature sensor is coupled to receive temperature signals; said method comprising: sending, from the at least one temperature sensor, a plurality of temperature signals over time to the evaluation device; detecting, with the evaluation device, a temperature trend based on the plurality of temperature signals sent from the at least one temperature sensor; and determining, with the evaluation device, an absence of flow in the line during operation of the pump, based on an increasing temperature trend indicative of heating of the pumping medium in the pumping chamber due to a lack of throughflow of the pumping medium.

2. The method of claim 1, further comprising providing a housing in which the pumping chamber is arranged, wherein the at least one temperature sensor is arranged in the housing.

3. The method of claim 1, further comprising driving an impeller of the feed pump with a motor, wherein the at least one temperature sensor is arranged on a housing of the motor.

4. The method of claim 1, further comprising providing the at least one temperature sensor arranged on or proximal to a wall of the pumping chamber.

5. The method of claim 1, wherein the temperature control device is integrated into the at least one temperature sensor.

6. The method of claim 5, wherein the temperature control device is either formed by at least one resistance heating element or comprises at least one heating element.

7. The method of claim 5, wherein the temperature control device is formed by one or more stator coils of a motor of the feed pump or comprises one or more stator coils of the motor, the defined temperature conditions are created by waste heat from the one or more stator coils, and the feed pump further comprises a heat conduction connection between the one or more stator coils and the area surrounding the at least one temperature sensor.

8. The method of claim 5, wherein the temperature control device comprises a temperature control chamber in which the at least one temperature sensor is arranged.

9. The method of claim 1, wherein the evaluation device comprises a temperature control member, the method comprising the temperature control member operating the feed pump without a flow of pumping medium for a specific duration of time in order to create defined temperature conditions in the area surrounding the at least one temperature sensor.

10. The method of claim 1, comprising detecting a presence of flow of the pumping medium from a decreasing temperature trend after a detected phase without flow.

11. The method according to claim 1, further comprising detecting a presence of flow in the line during operation of the pump based upon a decreasing temperature trend measured in the feed pump.

12. The method of claim 11, comprising the evaluation device generating the deactivation signal for operating the feed pump upon detecting the absence of flow.

13. The method of 12, comprising the evaluation device generating the deactivation signal either immediately after detecting the lack absence of flow, or when reaching a specific temperature threshold.

14. The method of claim 11, wherein the evaluation device generates the activation signal for the operation of the feed pump upon detecting the presence flow of the pumping medium after a phase of a lack of flow.

15. The method of claim 11, further comprising the evaluation device generating an activation signal to activate feed pump operation or a deactivation signal to deactivate feed pump operation.

16. The method of claim 1, comprising increasing the pressure in a line of an industrial water system.

17. The method of claim 1, comprising detecting the absence of flow of the pumping medium based upon linearity of the increasing temperature trend.

18. The method of claim 1, comprising determining the absence of flow during operation of the pump due to the lack of throughflow of the pumping medium by detecting a linearity of the increasing temperature trend for a known thermal mass and power consumption of the feed pump.

19. A feed pump for increasing pressure in a line, said feed pump comprising: a pumping chamber for a pumping medium, at least one temperature sensor configured for detecting a temperature of pumping medium in the pumping chamber, the at least one temperature sensor arranged in the feed pump, allocated to the pumping chamber, and in thermal contact with the pumping chamber, a temperature control device which is allocated to the at least one temperature sensor and by which defined temperature conditions can be created in an area surrounding the at least one temperature sensor, and an evaluation device to which the at least one temperature sensor is coupled for signal purposes, the evaluation device configured to use increasing temperature trend data from the at least one temperature sensor during operation of the pump to determine the pumping medium is not flowing through the pumping chamber, as indicated by heating of the pumping medium in the pumping chamber due to a lack of throughflow of the pumping medium.

20. The feed pump of claim 19, wherein the evaluation device is further configured to use decreasing temperature trend data from the at least one temperature sensor during operation of the pump to determine the pumping medium is flowing through the pumping chamber.

21. The feed pump according to claim 20, wherein the evaluation device is configured to provide activation signals to activate pump operation and deactivation signals to deactivate pump operation.

Description

BRIEF DESCRIPTION OF THE DRAWING FIGURES

(1) The description of preferred embodiments below aims to describe the invention in greater detail in combination with the drawings. In the drawings:

(2) FIG. 1 shows a schematic representation of an arrangement of a feed pump on a line with a valve;

(3) FIG. 2 shows a schematic sectional view of an embodiment of a feed pump according to the invention;

(4) FIG. 3 shows temperature signals in different arrangements of a temperature sensor in the feed pump according to FIG. 2 as they develop over time in different positions of a valve, wherein the feed pump is deactivated;

(5) FIG. 4 shows a similar diagram to that shown in FIG. 3 with the valve in various positions and showing activation of the feed pump;

(6) FIG. 5 shows a schematic representation of an embodiment of a temperature control device;

(7) FIG. 6 shows a further exemplary embodiment of a temperature control device; and

(8) FIG. 7 shows a further exemplary embodiment of a temperature control device.

DETAILED DESCRIPTION OF THE INVENTION

(9) An exemplary embodiment of an industrial water system which is partially shown in FIG. 1 and is designated 10 there comprises a line 12 on which a valve 14 is arranged. The valve 14 is for example arranged on a shower. If the valve 14 is open, then water flows from the shower.

(10) A feed pump 16 is arranged on the line 12. The feed pump 16 serves to increase the pressure in the line 12, in particular if the pressure provided by a waterworks is not sufficient.

(11) It is also possible for the industrial water system 10 to have a heating device 18 which is used to heat water that, for example, runs to a shower. It is often necessary for the water to be heated to be of a minimum pressure for the proper functioning of the heating device 18. The feed pump 16 can provide a minimum pressure of this type, including when a waterworks does not provide sufficient pressure.

(12) An embodiment of a feed pump 16 (circulating pump) is for example known from DE 10 2007 054 313 A1 or US 2009/0121034. Reference is expressly made to the full content of these documents.

(13) The pump 16 (FIG. 2) comprises an electric motor (20) with a stator 22 and a rotor 24.

(14) The electric motor 20 has a motor housing 26 in which the stator 22 and the rotor 24 are arranged.

(15) The electric motor 20 further has a motor circuit 28. The motor circuit 28 is arranged in a circuit housing 30. The circuit housing 30 can be formed separately to the motor housing 26 as shown in FIG. 2, or be formed by the motor housing 26.

(16) The rotor 24 is mounted above a bearing shell 32 on a convex bearing body 34 which is in particular formed as a bearing ball, for example made of ceramics. A spherical bearing is formed from the bearing body 34 and the bearing shell 32.

(17) An impeller 36 is non-rotatably connected to the rotor 24. The impeller 36 rotates about a rotational axis 38 in a pumping chamber 40. Pumping medium can flow through the pumping chamber 40, wherein the flow is driven by the impeller 36 when the pump is operating. If pumping medium is flowing through the pumping chamber 40, pumping medium is also flowing in the line 12. The pump can also be in operation (be activated) if there is no flow in the line 12 and therefore in the pumping chamber 40; if the valve 14 is closed then no pumping medium can be transported through the pumping chamber 40 and the line 12, wherein the rotor 24 is rotated using the impeller 36 when the feed pump 16 is activated.

(18) The feed pump 16 comprises a temperature sensor 42.

(19) The temperature sensor 42 is arranged and designed such that a temperature of pumping medium in the pumping chamber 40 can be determined using said temperature sensor.

(20) The temperature sensor 42 is preferably outside of the pumping chamber 40 in order not to affect the flow of pumping medium.

(21) The pumping chamber 40 is limited by a wall 44. In an exemplary embodiment the temperature sensor 42 is on the wall 44 outside of the pumping chamber 40. It can be placed, for example, directly on an outside of the wall 44 or at a small distance from this. It is in particular in thermal contact with the wall 44.

(22) It is preferably provided for the temperature sensor to lie on the motor housing 26 as indicated in FIG. 2 by reference number 46 and thereby to be in thermal contact with the pumping chamber 40.

(23) The feed pump 16 has an evaluation device 48 (FIG. 1). The temperature sensor 42 or 46 provides its temperature signals to the evaluation device 48. The evaluation device 48 is for example integrated into the motor housing 28.

(24) The feed pump 16 has a housing 50. The impeller 36 is arranged inside the housing 50. The electric motor 20 is arranged at least in part inside the housing 50. The temperature sensor 42 or 46 is arranged inside the housing 50.

(25) In an exemplary embodiment the housing 50 has a pump housing 51 as the first part of the housing and the motor housing 26 as the second part of the housing. The motor housing 26 lies on the pump housing 51. The impeller 36 is positioned in the pump housing 51. The temperature sensor 42 lies in the housing 50 and therefore in the pump housing 51. The temperature sensor 46 lies in the motor housing 26.

(26) It is advantageous for the temperature sensor 46 to be used for the simple disassembly of the electric motor 20 from the pump housing 51. This means that no cable connections for the temperature sensor need to run into the pump housing 51.

(27) Taking the signals from the temperature sensor 42 or 46 as a basis, the evaluation device 48 can determine whether pumping medium is flowing through the pumping chamber 40 and therefore the line 12.

(28) In an embodiment a temperature control device 52 is allocated to the temperature sensor (for example temperature sensor 42). The temperature control device 52 ensures that defined temperature conditions are in place in an area 54 surrounding the temperature sensor 42. This means changes in temperature over time can be allocated directly to changes in the temperature of the pumping medium in the pumping chamber 40.

(29) In an embodiment the temperature control device 52 comprises a temperature control chamber 56. This has a housing 58, in particular made of a thermally insulating material. The temperature sensor 42 (or 46) is then arranged in the housing 58 and is in thermal contact with the pumping chamber 40. For example, it is arranged directly on the wall 44 or there is a heat conduction connection between the wall 44 and the temperature sensor 42 or 46 and the housing 58.

(30) In an embodiment (FIG. 5) the temperature control device 52 comprises at least one heating element 60 and in particular a resistance heating element which is arranged in the temperature control chamber 56. By applying electricity to the heating element 60 in a corresponding manner, a defined temperature can be set in the temperature control chamber 56 and therefore in the area 54 surrounding the temperature sensor 42 or 46. The temperature set is selected in relation to the temperatures of the pumping medium to be expected in the line 12.

(31) In a further embodiment, a schematic representation of which is shown in FIG. 6, a temperature sensor 42′ is provided which is arranged in a temperature control chamber 56. The temperature control chamber is fundamentally designed as described above. Like reference numbers are used for like elements.

(32) The temperature sensor 42′ is designed such that a heating element is integrated into it. It is therefore part of the temperature control device 52. The temperature sensor 42′ is for example designed as an NTC (thermistor), which also generates heat as a result of an electric current.

(33) In a further embodiment (FIG. 7), a temperature control chamber is once again provided corresponding to temperature control chamber 56. The temperature sensor 42 or 46 is provided as a temperature sensor.

(34) One or more heat conduction connections 62 lead from the one or more coils of the stator 22 of the electric motor 20 of the feed pump 16 to the temperature control chamber 56 and in particular into the temperature control chamber 56. Waste heat from one or more coils of the stator 42 can be used to achieve a defined control of the temperature of the area 54 surrounding the temperature sensor 42 or 46 in order to increase the temperature in the area surrounding the temperature sensor 42 or 46 to a temperature above the temperature of the pumping medium when there is no flow. This means the start of flow can easily be identified.

(35) It is, for example, also possible for the evaluation device 48 to comprise a temperature control member 64. The temperature control member 64 ensures that the feed pump 16 is operated (in other words the impeller 36 rotates) without the flow of pumping medium through the pumping chamber 40. This means defined temperature conditions can be created in the area 54 surrounding the temperature sensor 42 or 46. The temperature control member 64 then functions as a temperature control device 52.

(36) FIG. 3 shows a diagram of temperature values over time, wherein the curve 66 corresponds to temperature values which are determined using the temperature sensor 42 and the curve 68 corresponds to temperature values which are determined using the temperature sensor 46.

(37) The feed pump 16 was activated, in other words operating, for the corresponding measurement.

(38) The valve 14 was closed at a point in time 70.

(39) The closed valve 14 means no further pumping medium (in particular water) can flow through the line 12. The water can also no longer flow through the pumping chamber 40. Since the feed pump 16 is activated, the rotor 24, and therefore the impeller 36, rotates in the pumping chamber 40. The electrical power is converted to heat, leading to a heating up of the pumping medium in the pumping chamber 40. The pumping medium no longer flows through the pumping chamber 40, in other words no longer enters through an inlet and leaves through an outlet, but rather it flows within the pumping chamber 40. The impeller 36 rotates, wherein the feed pump 10 recirculates as much pumping medium as can move from the pressure side back to the suction side at maximum pump pressure through a suction nozzle gap without external flow. This leads to an increase in temperature 72 over time. This increase in temperature can be detected by the evaluation device 48.

(40) It has been demonstrated that this temperature increase 72 is at least approximatively linear over time.

(41) The valve is reopened at a point in time 74. Pumping medium is then able to flow through the line 12 and therefore also through the pumping chamber 40. This leads to a reduction in temperature 76 over time. This reduction in temperature 76 over time, which is determined solely by pump parameters and in particular by the thermal mass of the feed pump 16 and the power consumption at zero throughput, can in turn be detected by the evaluation device 48.

(42) The feed pump 16 can to a certain extent determine whether there is a flow in the line 12 or not using “on-board means”. The means have a non-mechanical flow monitor.

(43) This in turn can be used to control the feed pump 16 itself.

(44) If for example an increase in temperature 72 over time is detected by the evaluation device 48, there are provisions for this to generated a deactivation signal to deactivate the feed pump 16, in other words to switch off the feed pump 16. This switching off means that the rotor 24 is no longer rotated relative to the stator 22.

(45) The switching off can occur immediately when an increase in temperature 72 is detected over time, or can occur when a certain (upper) temperature threshold is reached. This temperature threshold can in turn be determined directly by the temperature sensor 42 or 46 or the corresponding duration can in particular be calculated using a linear increase in temperature 72 over time as a basis.

(46) Before the point in time 70, FIG. 3 shows a state 78 with an approximatively constant temperature. This state 78 corresponds to a state in which the feed pump 16 is activated, in other words pumping medium is being pumped and flows out of the line 12 when the valve 14 is open. The temperature in the state 78 corresponds to the temperature at which pumping medium is provided by a waterworks.

(47) A similar diagram as that in FIG. 3 is shown in FIG. 4. The valve 14 is closed at a point in time corresponding to point in time 70. The increase in temperature 72 over time then occurs.

(48) At a later point in time 80, the feed pump 16 is then deactivated, in other words the impeller 36 no longer rotates in the pumping chamber 40. This results in a slight reduction in temperature 82 over time, which in particular is due to natural convection.

(49) At a later point in time 84, the valve 14 is opened again. A reduction in temperature corresponding to the reduction in temperature 76 then occurs.

(50) As shown in the diagram according to FIG. 3, the curves are due to different positions of the temperature sensor. In the lower curve, the temperature sensor 42 provides its measurement data, in the upper curve it is temperature sensor 46.

(51) As shown in the diagram according to FIG. 4, the evaluation device can detect when a reduction in temperature 76 occurs starting from a status in which the feed pump 16 is deactivated. The reduction in temperature 76 after the point in time 84 is significantly greater than the gradual reduction in temperature 82. The evaluation device 48 can detect when the valve 14 is reopened. The feed pump 16 can detect this using “on-board means”.

(52) When it detects a reduction in temperature 76 after a merely gradual reduction in temperature 82, the evaluation device 48 generates an activation signal for the feed pump 16 so this is operated again, in other words to rotate the impeller 36 in the pumping chamber 40.

(53) The feed pump 16 according to the invention functions as follows:

(54) (at least) one temperature sensor 42 or 46 is integrated into the feed pump 16. This temperature sensor 42 or 46 is in particular arranged and designed in combination with the temperature control device 52 such that there are no significant changes in temperature in the area 54 surrounding it which are not due to changes in the temperature of the pumping medium in the pumping chamber 40.

(55) As can be seen in the diagrams according to FIGS. 3 and 4, the development of the temperature signals from the temperature sensor 42 or 46 over time can be used by the evaluation device 48 to detect whether there is low in the pumping chamber 40 (between an inlet and an outlet) and therefore flow in the line 12. The evaluation device 48 can determine whether the valve 14 is closed or open. A flow monitor is provided in this way.

(56) The evaluation device 48 generates a deactivation signal for the feed pump 16 when it determines that the valve 14 is closed, in other words there is no flow in the line 12. This can be detected in particular from an increase in temperature 72 over time, which in particular is at least approximatively linear.

(57) The evaluation device 48 provides the feed pump 16 with an activation signal when it determines that flow in the line 12 is possible while the feed pump 16 is deactivated.

(58) In particular, a reduction in temperature 76 which is more rapid over time than a reduction in temperature 82 that occurs when the feed pump 16 is deactivated can be used by the evaluation device 48 to detect that the valve 14, has been opened and that the feed pump 16 can be activated, in other words pumping medium can once again be transported through the pumping chamber 40 and therefore in the line 12.

(59) The feed pump 16 according to the invention detects whether there is a flow in the line 12 or not. It can to a certain extent switch itself on and off itself without additional mechanical means being required for this.

(60) The feed pump 16 according to the invention can for example provide an increase in pressure on an industrial water system 10 without additional mechanical means being required for this.

LIST OF REFERENCE SIGNS

(61) 10 Industrial water system

(62) 12 Line

(63) 14 Valve

(64) 16 Feed pump

(65) 18 Heating device

(66) 20 Electric motor

(67) 22 Stator

(68) 24 Rotor

(69) 26 Motor housing

(70) 28 Motor circuit

(71) 30 Circuit housing

(72) 32 Bearing shell

(73) 34 Bearing body

(74) 36 Impeller

(75) 38 Rotational axis

(76) 40 Pumping chamber

(77) 42 Temperature sensor

(78) 42′ Temperature sensor

(79) 44 Wall

(80) 46 Temperature sensor

(81) 48 Evaluation device

(82) 50 Housing

(83) 51 Pump housing

(84) 52 Temperature control device

(85) 54 (Surrounding) area

(86) 56 Temperature control chamber

(87) 58 Housing

(88) 60 Heating element

(89) 62 Heat conduction connection

(90) 64 Temperature control member

(91) 66 Curve

(92) 68 Curve

(93) 70 Point in time

(94) 72 Increase in temperature over time

(95) 74 Point in time

(96) 76 Reduction in temperature

(97) 78 State

(98) 80 Point in time

(99) 82 Reduction in temperature

(100) 84 Point in time