JPH08184480A - System for measuring flow rate of bearing lubricant to canned motor pump - Google Patents

Abstract

PURPOSE: To provide a system for measuring the flow rate of a bearing lubricant which is required for designing a canned motor pump so that an appropriate amount of bearing lubricant can be always supplied to bearings which support the rotor shaft of the canned motor of the pump by detecting the lubricated states of the bearings. CONSTITUTION: A canned motor pump is constituted in such a way that part of the liquid handled by the pump is circulated to the rotor chamber of its canned motor so as to lubricate the bearings of a rotor shaft and cool a motor section. By arranging high-resolution thermister thermometers 60a and 60b at a prescribed interval on the liquid flowing-in side and flowing-out side of bearings 30 and 32 and injecting a tracer liquid having a temperature difference against the liquid handled by the pump into the suction port of the pump, the temperature fluctuations of the bearings 30 and 32 caused when the liquid handled by the pump passes through the bearings 30 and 32 are respectively detected by means of the thermometers 60a and 60b. The rate of flow of a bearing lubricant is measured by comparing the time sequential temperature fluctuations detected by means of the thermometers 60a and 60b with each other and the flow rate of the lubricant is calculated from the measured rate of flow.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is designed to detect a lubrication state of a bearing that supports a motor rotor shaft in a canned motor pump so as to always obtain a proper flow rate of the lubricating liquid for the bearing. The present invention relates to a method for measuring the flow rate of the bearing lubricating liquid required for the above.

[0002]

2. Description of the Related Art Generally, a canned motor pump circulates and supplies a part of a pump handling liquid into a motor rotor chamber of a canned motor to cool the motor and lubricate a bearing.

That is, a part of the pump handling liquid taken out from the discharge pipe portion of the pump portion via the external conduit is introduced into the rear motor rotor chamber of the canned motor portion, and this handling liquid is cut into the inner peripheral surface of the rear bearing. The through hole formed in the bearing supporting member that supports the formed groove and the rear bearing is circulated. Then
The handling liquid introduced into the rear motor rotor chamber is transferred to the front motor rotor chamber through the space between the rotor and the stator of the motor unit. In this way, the handling liquid introduced into the front motor rotor chamber passes through the through hole formed in the bearing support member that supports the front bearing and the groove hole cut in the inner peripheral surface of the front bearing, and then the pump liquid. It is configured to flow back to the pump section via a liquid passage communicating with the low pressure section of the section.

Therefore, in the canned motor portion, when a part of the pump handling liquid flows through the groove holes on the inner peripheral surfaces of the rear bearing and the front bearing, the lubrication of the bearings is achieved.

[0005]

However, in the conventional canned motor pump described above, in order to smoothly lubricate the front and rear bearings, the pump handling liquid as the lubricating liquid always flows at an appropriate flow rate. It is necessary to. Therefore, in manufacturing this type of pump, it is necessary to design with due consideration of this point.

However, since the portion of the bearing through which the lubricating liquid flows is an extremely small gap, it is difficult to install a commercially available flow meter or the like to measure the flow rate of the lubricating liquid. It is possible to obtain a theoretical value for the flow rate of the lubricating liquid from the design dimensions of the bearing portion, but it is not possible to confirm the flow rate of the lubricating liquid generated in the bearing during actual pump operation.

Therefore, an object of the present invention is to provide a canned motor pump configured to circulate a part of the pump handling liquid into the rotor chamber of the canned motor to lubricate the bearing of the rotor shaft and cool the motor part. In the above bearing, a high resolution thermistor thermometer is used for the lubrication part of the bearing, and the flow velocity is measured based on the temperature detection between the two points of the lubricating liquid flowing through the inner peripheral surface of the bearing. An object of the present invention is to provide a method for measuring the flow rate of a bearing lubricating liquid in a canned motor pump, which is capable of simply and properly calculating the flow rate of the lubricating liquid.

[0008]

In order to achieve the above object, the method of measuring the flow rate of a bearing lubricating liquid in a canned motor pump according to the present invention circulates a part of a pumped liquid into a rotor chamber of a canned motor. In a canned motor pump configured to lubricate a rotor shaft bearing and cool a motor unit, a high resolution thermistor thermometer is arranged on the liquid inflow side and the liquid outflow side of the bearing at predetermined intervals. When a tracer liquid that has a temperature difference from the handled liquid is injected into the pump suction port side, and the temperature changes due to the flow of the pump handled liquid in the bearing are detected by the thermistor thermometers respectively, and when detected by each thermistor thermometer. The present invention is characterized in that the flow rate of the bearing lubricating liquid is measured by comparing the series temperature changes and the flow rate of the bearing lubricating liquid is calculated based on the obtained flow velocity.

In this case, the high resolution thermistor thermometer has an accuracy of 0.0 in the temperature range of 0 ° C to 100 ° C.
Use a 2 ° C, 0.001 ° C resolution.

Further, when measuring the flow rate of the bearing lubricating liquid, the thermistors are so arranged that the sensor portions are exposed on the liquid inflow side and the liquid outflow side of the through hole cut in the inner peripheral surface of the bearing. It is advantageous if the thermometer is arranged inside the bearing.

[0011]

According to the method of measuring the flow rate of the bearing lubricating liquid in the canned motor pump according to the present invention, a high-resolution thermistor thermometer is arranged at a predetermined distance on the liquid inflow side and the liquid outflow side of the bearing, respectively, and pump suction is performed. By injecting a tracer liquid of high temperature water into the mouth side and detecting the temperature change due to the flow of the pump handling liquid in the bearing respectively by the thermistor thermometer, the time series temperature change detected by the thermistor thermometer is detected. By comparison, the flow rate of the bearing lubricating liquid can be measured, and the flow rate of the bearing lubricating liquid can be measured and calculated properly and easily based on the obtained flow velocity.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for measuring the flow rate of a bearing lubricating liquid in a canned motor pump according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a schematic sectional view of a canned motor pump for carrying out the method for measuring the flow rate of a bearing lubricating liquid according to the present invention. In FIG. 1, reference numeral 10 denotes a pump unit, 12 denotes a canned motor unit, and the pump unit 10 and the motor unit 12
Are connected to each other by an adapter 14 so as to be compatible with each other.

The pump portion 10 has a suction pipe portion 20 and a discharge pipe portion 22 which communicate with the inside of a pump chamber 18 provided with an impeller 16.
And the impeller 16 is attached to the extended end of the rotor shaft 24 of the motor unit 12. On the other hand, the motor unit 1
2 includes a stator assembly 26 and a rotor assembly 28, the rotor shaft 24 is supported by a front bearing 30 and a rear bearing 32, respectively, and a front rotor chamber 34 and a rear rotor chamber 36 are provided at both ends of the rotor assembly 28, respectively. Are formed.
However, at the rear end of the rear rotor chamber 36, the pump unit 1
The external conduit 38 led out from the discharge pipe portion 22 of No. 0 is connected for communication.

In this way, a part of the liquid to be handled is introduced into the rear rotor chamber 36 from the discharge pipe 22 of the pump unit 10, and the liquid to be handled is cut into the inner peripheral surface of the rear bearing 32. Bearing support member 42 supporting the hole 40 and the rear bearing 32
It is circulated through the through hole 44 formed in the rear part to lubricate the rear bearing and cool the motor part 12. The rear rotor chamber 36
The handling liquid introduced therein is transferred to the front rotor chamber 34 via the rotor-stator space 46.

The adapter 14 also includes a front rotor chamber 3
4 is provided with a liquid passage 48 that communicates with the low-pressure side of the pump unit 10. That is, the liquid passage 48 is provided through the through hole 52 formed in the bearing support member 50 for supporting the front bearing 30 and the groove hole 54 cut in the inner peripheral surface of the front bearing 30 to form the front rotor chamber. The handling liquid, which communicates with the bearing 34 and lubricates the front bearing 30 and cools the motor unit 12, is led out to the liquid passage 48. Then, the handled liquid led to the liquid passage 48 passes from the back surface of the impeller 16 in the pump chamber 18 to the balance hole 56 formed in the impeller 16 and then passes through the impeller 16.
Will be guided to the suction port side.

However, in the present invention, in the front bearing 30 and the rear bearing 32, the liquid inflow side and the liquid outflow side are respectively formed in the groove holes 40 and 54 cut in the inner peripheral surfaces of the respective bearings 30 and 32. In the above, the pair of high resolution thermistor thermometers 60a and 60b are exposed so that the respective sensor portions are exposed in the respective groove holes 40 and 54, and the bearings 30 and 3 are
Place inside 2.

As the high-resolution thermistor thermometers 60a and 60b which can be used in the present invention, for example, Model 3312 thermometers and Model 4312 thermometers manufactured by Instrument Lab, USA are suitable, and in this case 0 In the temperature measurement range of 100 ° C to 100 ° C, accuracy of 0.02 ° C and resolution of 0.001 ° C can be obtained.

The lead wires of the thermistor thermometers 60a and 60b arranged inside the bearings 30 and 32 are
The connection structure part of the canned motor part 12 is appropriately led in a liquid-tight manner and arranged so as to be externally connectable.

Next, measurement of the flow rate of the lubricating liquid in each bearing 30, 32 in the canned motor pump having the above-mentioned structure will be described.

First, a tracer liquid having a temperature difference from that of the pump handled liquid is prepared on the pump suction port side, for example, a tracer liquid of higher temperature water than the handled liquid is prepared, and the tracer liquid is pumped from the suction pipe portion 20 through the pump chamber 18 as the pump operates. Introduce inside. Due to the pump operation, a part of the tracer liquid discharged from the pump unit 10 is introduced into the rear rotor chamber 36 via the external conduit 38 and flows through the groove 40 of the rear bearing 32. At this time, the temperature of the tracer liquid is detected by the thermistor thermometer 60a arranged on the liquid inflow side. Next, the temperature of the tracer liquid is detected by the thermistor thermometer 60b arranged on the liquid outflow side.

Therefore, assuming that the time points at which the thermistor thermometers 60a and 60b detect temperature changes due to the flow of the tracer liquid are t1 and t2, respectively, the distance l between the measurement points of the thermistor thermometers 60a and 60b is 1 The flow velocity v of the tracer liquid in can be calculated by the following equation.

V = 1 / (t2-t1) (1)

Therefore, when the flow velocity v of the tracer liquid is obtained in this way, if the cross-sectional area of the groove hole 40 of the rear bearing 32 through which the tracer liquid flows is A, the tracer liquid flowing through this cross section will be described. The flow rate (volume flow rate) of can be calculated by the following equation.

Q = v · A (2)

The outline of the arithmetic circuit for measuring the flow rate of the tracer liquid described above is as shown in FIG. In FIG. 2, reference numeral 62 is a flow velocity calculator that calculates the flow velocity v of the tracer liquid, and 64 is a flow rate calculator that calculates the flow amount q of the tracer liquid.

Further, the slot 40 of the front bearing 30 shown in FIG.
Even when the tracer liquid flows through, the flow velocity and flow rate of the tracer liquid can be measured and calculated in the same manner as described above.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and many design changes can be made without departing from the spirit of the present invention.

[0029]

As is apparent from the embodiments described above, according to the method for measuring the flow rate of the bearing lubricating liquid in the canned motor pump according to the present invention, a part of the pump handling liquid is circulated and introduced into the rotor chamber of the canned motor. In a canned motor pump configured to lubricate the rotor shaft bearing and cool the motor part, high-resolution thermistor thermometers are arranged on the liquid inflow side and the liquid outflow side of the bearing at predetermined intervals. Injecting a tracer liquid having a temperature difference from the liquid to be handled into the pump suction port side, temperature changes due to the flow of the liquid to be handled by the pump in the bearing were detected by the thermistor thermometers, and detected by the thermistor thermometers. By comparing the temperature changes over time, the flow velocity of the bearing lubricating liquid is measured, and the flow rate of the bearing lubricating liquid is calculated based on the obtained flow velocity. , The actual flow rate of the lubricating liquid in the bearing of the prior difficulties and have been canned motor pump can be properly and easily measured.

Therefore, according to the present invention, the effect of contributing to the design of the circulation system of the lubricating liquid for the bearing of the canned motor pump, that is, the pump handling liquid, is extremely large.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a configuration of a canned motor pump that implements a method for measuring a flow rate of a bearing lubricating liquid in a canned motor pump according to the present invention.

FIG. 2 is a block circuit diagram showing an embodiment of an arithmetic circuit for carrying out the method for measuring the flow rate of the bearing lubricating liquid according to the present invention.

[Explanation of symbols]

 10 pump part 12 canned motor part 14 adapter 16 impeller 18 pump chamber 20 suction pipe part 22 discharge pipe part 24 rotor shaft 26 stator assembly 28 rotor assembly 30 front bearing 32 rear bearing 34 front rotor chamber 36 rear rotor chamber 38 external conduit 40 groove 42 42 bearing support member 44 through hole 46 rotor-stator 48 fluid passage 50 bearing support member 52 through hole 54 groove hole 56 balance hole 60a, 60b thermistor thermometer 62 flow velocity calculator 64 flow calculator

Claims (3)

[Claims] 1. A canned motor pump configured to circulate a part of a pump handling liquid into a rotor chamber of a canned motor to lubricate a bearing of a rotor shaft and cool a motor part of the canned motor pump. The high-resolution thermistor thermometers are placed on the liquid side and the liquid outflow side with a predetermined distance from each other.
When a tracer liquid that has a temperature difference from the handled liquid is injected into the pump suction port side, and the temperature changes due to the flow of the pump handled liquid in the bearing are detected by the thermistor thermometers respectively, and when detected by each thermistor thermometer. A method for measuring the flow rate of a bearing lubricating liquid in a canned motor pump, which comprises measuring the flow velocity of the bearing lubricating liquid by comparing the temperature changes and calculating the flow rate of the bearing lubricating liquid based on the obtained flow velocity. 2. The high resolution thermistor thermometer is 0 ° C.
In the temperature measurement range of 100 ° C., at least accuracy of 0.
The method for measuring the flow rate of a bearing lubricating liquid in a canned motor pump according to claim 1, wherein the method has a temperature of 02 ° C and a resolution of 0.001 ° C. 3. A thermistor thermometer arranged on the bearing is provided inside the bearing such that the sensor portions are exposed on the liquid inflow side and the liquid outflow side of the through hole cut in the inner peripheral surface of the bearing. The method for measuring the flow rate of a bearing lubricating fluid in a canned motor pump according to claim 1, wherein the method is used.