JP2006162296A - Impeller flow meter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an impeller flow meter with a simple constitution which is capable of reducing a system cost and running cost. <P>SOLUTION: The variation of magnetic flux from a magnet 5 provided on a blade 4a of an impeller 4 is detected with a magnetic detector element 6 such as Hall IC provided on the flow meter body 1 outside the flow path to detect the revolution number of the impeller and flow rate of fluid is measured from the revolution number of the impeller. The impeller flow meter keeps one end of a rodlike heat absorbing member 10 with a large heat conductivity in contact with the magnetic detector element 6, the other end connected to a radiation fin 11 contacting the air. Between the radiation fins and the flow meter body, an insulator 17 consisting of the first thermal insulator on the flow meter side and the second insulator on the radiation fin side and an insulation space formed between the first and the second insulators are put. The radiation fins are attached to the flow meter body 1 with screws made of a stuff having insulation performance. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an impeller flow meter that obtains the flow rate of a fluid to be measured from the number of revolutions of an impeller provided in the flow path, and more specifically, can exhibit sufficient measurement performance for measuring the flow rate of a high temperature fluid to be measured. Related to the impeller flowmeter.

  The impeller flowmeter is a means for obtaining the flow rate of the fluid to be measured from the rotational speed of the impeller rotated around the axis by the fluid pressure of the fluid to be measured flowing in the flow path, and means for detecting the rotational speed of the impeller The magnet is built in the blade of the impeller, and the change of magnetic flux from the magnet accompanying the rotation of the impeller is detected by the magnetic detection element such as Hall IC provided on the flowmeter body side near the rotation locus of this magnet. Thus, the rotational speed of the impeller is obtained, and the flow rate of the fluid to be measured is obtained from the rotational speed of the impeller (see, for example, Patent Documents 1 and 2).

  By the way, in general, the magnetic sensing element may not be able to exhibit its performance sufficiently under high temperature conditions or may be damaged. The operating temperature of a commercially available Hall IC is, for example, about −30 ° C. to + 115 ° C. Inevitably, the temperature of the fluid to be measured is also limited to the operating temperature of the Hall IC.

  For example, when measuring the flow rate of the fluid to be measured at 100 ° C. or higher, a cooling electric fan is conventionally provided in the vicinity of the Hall IC.

However, there is a problem that electric power for operating the electric fan is required and the cost of the apparatus is increased and the apparatus size is increased by the provision of the electric fan.
JP-A-63-100326 (pages 1 to 4 and FIGS. 1 to 3) JP-A-63-100327 (pages 1 to 4 and FIGS. 1 to 3)

  An object of the present invention is to provide an impeller flow meter that has a simple configuration, can reduce apparatus cost, and can reduce running cost.

  In order to achieve the above object, an impeller flowmeter according to the present invention is a magnet provided on a blade of the impeller, the impeller being rotated by a fluid to be measured flowing in a flow path from the inlet to the outlet. An impeller flowmeter that detects the flow rate of the fluid to be measured from the rotational speed of the impeller by detecting the rotational speed of the impeller by detecting the change in magnetic flux from the magnetic flow sensor in the flowmeter body outside the flow path In this embodiment, a heat absorption member having a high thermal conductivity is brought into close contact with the magnetic detection element.

  Further, the heat absorbing member is formed of a rod-shaped member, and the other end of the heat absorbing member having one end in close contact with the magnetic detection element is connected to a heat radiating fin in contact with outside air, and the heat radiating fin, the flow meter body, In between, the heat insulation part which consists of the heat insulation space formed between the 1st heat insulation member by the side of a flow meter main part, the 2nd heat insulation member by the side of a radiating fin, and the 1st and 2nd heat insulation members, The heat dissipating fin is attached to the main body of the flowmeter with a screw made of a heat insulating material.

  Further, a portion other than the contact portion with the heat absorbing member on the surface of the magnetic detection element is covered with a heat insulating material so that the magnetic detection element and the flowmeter main body do not come into contact with each other.

  According to the present invention, the heat conducted from the fluid to be measured to the flowmeter body is suppressed from being conducted to the magnetic detection element by the heat insulating material around the magnetic detection element, and the heat conducted to the magnetic detection element is applied to the magnetic detection element. Therefore, the magnetic sensing element is prevented from being damaged due to high temperature and the measurement performance of the flow meter being deteriorated.

The heat conducted from the magnetic detection element to the heat absorbing member is conducted to the heat radiating fin, and the heat radiating fin releases heat by contact with the outside air.
Furthermore, since the heat radiating fin is attached to the flow meter main body by a screw having heat insulation properties, and a heat insulating portion is provided between the heat flow fin main body, the heat radiating fin efficiently only sends heat from the magnetic detection element to the outside. There is almost no possibility of releasing and lowering the temperature of the fluid to be measured.

Therefore, it is possible to measure the flow rate of a high temperature fluid to be measured with high accuracy without providing an electric fan for cooling unlike the conventional one, and the configuration can be simplified and the apparatus size can be reduced. .
Further, the driving power of the electric fan is not necessary, and the running cost can be reduced.

Embodiments of an impeller flowmeter according to the present invention will be described in detail below based on specific examples shown in the accompanying drawings.
The flow meter main body 1 has an impeller chamber 3 in the middle of the flow path 2 of the fluid to be measured extending from the inlet 2a to the outlet 2b. The impeller 4 is provided in the impeller chamber, and a magnet 5 Are configured so that the tip portions of the blades 4a and 4a that respectively house the blades face the flow path 2 and can freely rotate around the shaft 4b.

  The impeller is rotated around the shaft 4b by the fluid pressure of the fluid to be measured flowing through the flow path 2, and the magnet 5 is also rotated on the circular track along with the rotation.

  The flow meter body 1 in the vicinity of the rotation trajectory of the magnet is provided with a Hall IC 6 serving as a magnetic detection element on the outside of the flow meter body 1 separated from the flow path by the wall 1a. Therefore, the rotation of the impeller is obtained as a change in magnetic flux detected by the Hall IC, and is output to the outside by the signal line 7.

  Thus, the Hall IC 6 is potted with the silicone resin 9 which is also a heat insulating material in the recess 8a of the holder 8 made of a heat insulating material such as polyphenylene sulfide resin.

  The end face of the heat absorbing member 10 penetrating the hole formed in the recess 8a of the holder is in close contact with the back surface of the Hall IC 6, that is, the surface opposite to the flow path 2, and between the Hall IC 6 and the heat absorbing member. An adhesive or thermal grease with high thermal conductivity is interposed.

  The heat-absorbing member 10 is made of a rod made of a material having a high thermal conductivity such as copper or aluminum, and the end opposite to the end in close contact with the Hall IC 6 is provided with a thermal conductivity. It is connected so as to be in close contact with the heat radiating fins 11 with a large amount of adhesive or heat radiating grease.

  The heat dissipating fins 11 are made of aluminum, for example, and are attached to the flowmeter main body 1 with screws 12 so that the heat dissipating surface is in contact with the outside air. The screws are made of a heat insulating material such as polyphenylene sulfide resin. Therefore, heat from the flowmeter body is not conducted to the heat radiating fins via the screws.

A first heat insulating member 13, a spacer 14, and a second heat insulating member 15 are interposed around the screw 12 between the flow meter main body 1 and the heat radiating fins 11. The heat insulating portion 17 including the space 16 formed by the heat insulating member and the spacer 14 is provided, so that heat conduction from the flow meter main body to the heat radiating fin can be prevented more reliably.
In addition, the said 1st and 2nd heat insulation members 13 and 15 are comprised with the board | plate material which consists of heat insulating materials, such as polyphenylene sulfide resin, for example.

In the impeller flowmeter of the present invention configured as described above, a graph of test results obtained by measuring the temperature of each part is shown in FIG.
In the above test, the endothermic member 10 is made of copper having a diameter of 4 mm and a length of 25 mm, the radiating fin 11 is made of aluminum having a radiating area of 70 cm ² , the outside air temperature is 30 ° C., and the temperature of the fluid to be measured is 150. Measured as ° C.

  As shown in the graph of FIG. 3, it was found that the Hall IC 6 was maintained at 70 ° C. by heat from the fluid to be measured, and a sufficient operating temperature was ensured.

  Furthermore, for the purpose of verifying how the temperature of the Hall IC 6 changes with a change in the outside air temperature, the above-described test is performed by measuring the temperature change of the Hall IC 6 while changing only the outside air temperature. The measurement result of the graph shown in FIG. 4 was obtained.

  As shown in the graph of FIG. 4, it was found that the Hall IC temperature was sufficiently maintained within the operating temperature range even when the outside air temperature changed.

  In the impeller flow meter of the embodiment described above, the holder 8, the screw 12, and the first and second heat insulating members 13 and 15 are all made of polyphenylene sulfide resin, but have a low thermal conductivity. Other materials may be used as long as they have electrical insulation properties and heat resistance and can provide sufficient structural strength.

The longitudinal section of the impeller flow meter concerning the present invention. The cross-sectional view of the impeller flowmeter according to the present invention. The graph which shows the temperature of each part of a flow meter. The graph which shows the relationship between outside temperature and Hall IC temperature.

Explanation of symbols

1 Flow meter body
2 Channel
3 impeller room
4 impeller
5 Magnet
6 Hall IC
7 signal lines
8 Holder
DESCRIPTION OF SYMBOLS 9 Silicone resin 10 Endothermic member 11 Radiation fin 12 Screw 13 1st heat insulation member 14 Spacer 15 2nd heat insulation member 16 Space for heat insulation 17 Heat insulation part

Claims (6)

  The impeller is rotated by the fluid to be measured that flows in the flow path from the inlet to the outlet, and the magnetic flux change from the magnet provided on the impeller blade is detected in the flow meter body outside the flow path. In the impeller flowmeter that detects the rotational speed of the impeller by detecting with the element and obtains the flow rate of the fluid to be measured from the rotational speed of the impeller, a heat absorbing member having a large thermal conductivity is provided on the magnetic detection element. An impeller flow meter that adheres closely.   2. The impeller flow meter according to claim 1, wherein the heat absorbing member is formed of a rod-like member, and the other end of the heat absorbing member having one end in close contact with the magnetic detection element is connected to a heat radiating fin that contacts outside air. .   The impeller flow meter according to claim 2, wherein a heat insulating portion is interposed between the heat radiation fin and the flow meter body.   The said heat insulation part is comprised by the heat insulation space formed between the 1st heat insulation member by the side of a flowmeter main body, the 2nd heat insulation member by the side of a radiation fin, and the 1st, 2nd heat insulation member. The impeller flow meter described in 1.   The impeller flowmeter according to claim 2, wherein the radiating fin is attached to the main body of the flowmeter with a screw made of a heat-insulating material.   The impeller according to claim 1, wherein a portion of the surface of the magnetic detection element other than the contact portion with the heat absorbing member is covered with a heat insulating material so that the magnetic detection element and the flowmeter main body do not contact each other. Flowmeter.

Images