JPS59119215A - Flow rate detector - Google Patents

Abstract

PURPOSE:To eliminate air bubbles in a bearing and to rotate a rotor smoothly by charging a seal material in the gap between the blind hole of the bearing and a supporting shaft. CONSTITUTION:The rotor 4 rotates at a rotating speed proportional to the flow rate of fluid to be measured which flows to an exit passage 3 through the port 2a of an entrance passage 2 by the flow of the fluid to be measured. A permanent magnet 10 fixed to the supporting shaft 6 also rotates at the same speed with the rotor 4 and its rotation is detected by a hole IC14. The blind hole 7-1 of the bearing 7 is charged previously with the paste seal material which is soluble in the fluid to be measured, and then the tip part of the supporting shaft 5 is inserted into the blind hole 7-1. Consequently, the gap between the supporting shaft 5 and bearing 7 is charged with the seal material and no air bubble is left.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flow rate detector that is installed in piping to detect the flow rate of various fluids and generates a pulse signal with a frequency proportional to the flow rate.

A turbine-shaped rotor is provided in the center hole of the pipe-shaped main body so as to be rotatable about the same axis as that of the pipe-like main body, and the rotor rotates in proportion to the flow rate of the fluid to be measured flowing through the center hole of the main body. A flow rate detector has already been proposed that detects the flow rate by utilizing changes in the magnetic relationship between the permanent magnet piece attached to the rotor and the Hall IC provided on the main body side.

This flow rate detector can obtain highly accurate measurement values because the rotor and the detection section are not in contact with each other, but there is a problem with the bearing that supports the rotor. In other words, the hole into which one end of the support shaft of the 10-meter enters must be a blind hole in order to receive the force in the thrust direction applied to the rotor by the bearing located on the downstream side and the flow of the fluid to be measured, such as water.
Therefore, during the initial stage of use, air bubbles remain within the bearing. Under these conditions, the support shaft will rub directly against the bearing, making it impossible to achieve smooth rotation, resulting in lower flow rate and rotation.
The relationship with rotation speed is not constant. These bubbles are replaced by the fluid to be measured during use, but the period required for this replacement is not constant, which causes a decrease in the reliability of the detected flow rate value.

An object of the present invention is to provide a flow rate detector in which a highly reliable flow rate detection value can be obtained from the initial stage of use by filling the blind hole of a bearing with a specific sealing material in advance. It is an object.

Next, one embodiment of the present invention will be described with reference to the drawings. In FIG. 1, an inlet passage 2 and an outlet passage 3 are formed in the main body designated by reference numeral 1, and the axes of the inlet passage 2 and the outlet passage 3 are arranged to be perpendicular to each other.
A rotor 4 is provided at the intersection of the two. This rotor 4 has a spiral or turbine shape,
It is arranged so that its axis coincides with the axis of the exit boat 3, and is supported by the main body 1 via bearings 7 and 8, respectively, by support shafts 5 and 6 protruding from both ends.

As shown in FIGS. 3 and 4, one of the bearings 7 is configured so that the fluid to be measured (for example, water) that flows into the inlet passage 2 and contacts the rotor 4 to rotate it passes through the outlet passage 3. A center portion 7-2 having a blind hole 7-1 into which the tip of the support shaft 5 enters so that it can flow outside;
It consists of a plurality of leg parts 7-3 extending radially from the main body 1, and the tips of the leg parts 7-3 are fixed in a predetermined position by fitting into the recesses of the main body 1. The other bearing 8 is
It is a disc-shaped member having a through hole in the center through which the support shaft 6 passes, and is fixed in a predetermined position by fitting into a recess in the main body 1 at its peripheral edge.

Further, a ring-shaped permanent magnet 1o housed in a plastic case 9 is attached to the tip of the support shaft 6.

The inlet passage 2 is provided at a position such that an extension of its axis intersects the axis of the rotor 4 at approximately the center of its length, and the fluid to be measured flowing in from the inlet passage 2 is directed to the rotor 4. Boat 2a
is formed.

As shown in FIG. 2, this boat 2a is formed at a position where only about half of the rotor 4 can be seen when viewed from the axial direction of the inlet passage 2, and therefore the measured fluid that has passed through this port 2a This flow acts to rotate the rotor 4 in one direction.

On the other hand, a plate 12 is fixed to the main body 1 with bolts 13 between the bearing 8 and the plate 12 so as to form a closed chamber 11 that houses the permanent magnet 10 and its cover 9. A plastic case 16 for supporting this position is fixed to the plate 12 by means of adhesive or the like. This case 16
supports a plurality of terminals 17 (five in this example), and a Hall IC 14 and a thermistor 15 are connected to the terminals 17.
Each lead wire is connected.

Note that the reference numeral 1 indicates a filler such as epoxy resin that fills the space inside the cover 15.

The rotor 4 rotates at a rotational speed proportional to the flow rate of the fluid to be measured due to the flow trap of the fluid to be measured through the port 2a of the inlet passage 2 toward the outlet passage 3. The permanent magnet 10 fixed to the support shaft 6 also rotates at the same speed as the rotor 4, and this rotation is detected by the Hall IC 14 facing the rotor 4 with the plate 12 in between. Assuming that the permanent magnet 10 has a pair of N and S poles formed in its circumferential direction, the Hall IC
14 generates one pulse every time the permanent magnet 10 rotates once, and this pulse is sent to an external circuit via a terminal 17. Since the rotational speed of the rotor 4 is proportional to the flow rate of the fluid to be measured flowing from the inlet passage 2 to the outlet passage 3, the flow rate can be detected by counting the frequency of the output pulses of the Hall IC 14. Furthermore, when the thermistor 15 is provided, it is also possible to detect the temperature of the fluid to be measured.

In the flow rate detector having such a configuration, the blind hole 7-1 of one of the bearings 7 is filled in advance with a paste-like sealing material that is soluble in the fluid to be measured, and then the blind hole 7-1 is filled with a paste-like sealing material that is soluble in the fluid to be measured.
The tip of the support shaft 5 is inserted into -1. As a result, the gap between the support shaft 5 and the bearing 7 is filled with the sealing material, and no air bubbles are present. When the fluid to be measured is water,
As the sealing material, commercially available antifoaming agents for food additives, silicone oil, etc. can be used.

Such a sealant reduces the friction between the bearing 7 and the support shaft 5 by its own lubricity in the initial stage of use, and gradually replaces the fluid to be measured during use. Therefore, in the same way as when the fluid to be measured is forcibly injected between the bearing 7 and the support shaft 5 to expel air bubbles before use, smooth rotation of the rotor 4 can be obtained immediately after the start of use.

As described above, according to the present invention, by filling the gap between the blind hole of the bearing and the support shaft with a sealing material, the rotor runs smoothly compared to the case where air bubbles exist in this gap. rotation is obtained, and the accuracy of the detected flow rate value is guaranteed from the beginning of use. Therefore, the trouble and time required to forcibly inject the fluid to be measured into the bearing or to check and inspect the rotational speed under actual usage conditions can be omitted. Furthermore, if a non-volatile material such as silicone oil is used as the sealing material, the same effect will be maintained even after storage for a long period of time after manufacture.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view of a flow rate detector according to an embodiment of the present invention, Fig. 2 is a side view of its main body, Fig. 3 is a front view of a bearing, and Fig. 4 is a line taken along line A-A in Fig. 3. FIG. 1... Main body, 2... Inlet passage, 3... Outlet passage,
4... Rotor, 5, 6... Support shaft, 7...
・Bearing, 7-1... Blind hole, 7-2... Center part, 7-3... Leg part, 8... Bearing, 10.
...Permanent magnet, 12...Plate, 14...Hall IC, 15...Thermistor, 16...Case. Patent applicant: Yamatake Honeywell Co., Ltd. No. 4
Figure 3 Figure 102-

Claims (1)

[Claims] A main body having an inlet passage and an outlet passage arranged so that their axes are substantially orthogonal to each other, and an axis arranged so that the axis at the intersection of the inlet passage and the outlet passage is parallel to the axis of the outlet passage. a turbine-shaped rotor, a pair of bearings that rotatably support the rotor at a predetermined position, a permanent magnet that rotates together with the rotor, and a permanent magnet that is disposed at a position facing the permanent magnet and that rotates the permanent magnet. The bearing located on the downstream side includes a Hall IC that generates pulses with a frequency proportional to the speed, and has a center portion having one hole into which one shaft end of the rotor is inserted, and a hole extending radially from the center portion. A flow rate characterized in that a plurality of legs extend and engage with the peripheral wall of the outlet passage, and the blind hole is filled in advance with a pasty sealing material that is soluble in the liquid to be measured. Detector.