JPH08203400A - Flow switch - Google Patents

Abstract

PURPOSE: To provide a flow switch which can be operated stably without being obstructed by waste in fluid, is small, inexpensive, and has a wide range of applications. CONSTITUTION: Stoppers 5, 13 are provided respectively above and below a fluid passage having an axially extending noncircular surface formed on its inner periphery, a float 4 that is kept from rotating by the noncircular surface is provided in the fluid passage between the stoppers, and a magnet 9 is secured to the outer periphery of the float. A Hall IC 8 which detects the magnetic force of the magnet to correspond to the position to which the magnet has been moved is provided on the wall of the fluid passage so as to constitute a flow switch.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow switch for detecting a displacement of a float arranged in a fluid flow path to generate a signal indicating that a fluid of a predetermined flow rate or more is flowing.

[0002]

2. Description of the Related Art Various means have been adopted as means for measuring the amount of fluid flowing in a pipe. However, when it is sufficient to know the approximate value of the flow rate, it is necessary to determine whether or not a fluid of a predetermined flow rate or more is flowing. When it is sufficient to know the approximate value, a float switch is provided in the flow path so as to be movable up and down, and a flow switch is often used to detect that the float rises by the fluid when the fluid flows for a predetermined amount or more.

In the conventional float type flow switch as described above, a substantially vertical flow path portion is provided in a vertical flow path or a horizontal flow path, and a guide shaft is fixed to the vertical flow path portion. A center hole of the float is loosely fitted to the shaft, a magnet is fixed to the float, and a reed switch that detects the movement of the magnet is provided on the outer wall of the flow path or in the hollow portion inside the guide shaft. This causes the fluid to flow in the flow path to raise the float against its gravity, and when the fluid flows for a predetermined amount or more, the float rises to a predetermined height or more, and the magnet provided on the float acts as a reed switch. By operating, it is detected that the fluid is flowing in the flow path at a predetermined flow rate or more.

[0004]

In the above-mentioned conventional flow switch, the float is constructed so as to move up and down along the guide shaft, in which case the center hole of the float is loosely fitted on the guide shaft and slides. Since it is configured to move up and down by moving, dust is likely to be caught in the gap between the outer circumference of the guide shaft and the inner circumference of the center hole. However, even though no fluid is flowing in the pipe, the float does not descend and causes various malfunctions.

Particularly, when such a float type flow switch is provided in the reheating circulation path of the bath,
Since hair and dirt in the bath flow through the reheating circulation path, in the reheating circulation path configured to detect the operation of the circulation pump by the flow switch placed in this circulation path and operate the gas burner, When hair etc. is caught on the flow switch, the gas burner does not operate and the reheating is not performed even though the circulation pump operates and hot water circulates in the circulation path. Even if the circulation pump is stopped after the operation and the circulation of the hot water is stopped, the flow switch catches and if it does not descend, it is falsely detected that fluid is flowing and the gas burner is not stopped, so the heat exchanger abnormally heats and burns out. It can be a cause.

As a countermeasure, it is conceivable to enlarge the float to increase the weight and increase the restoring force of the float. However, if the float is enlarged, a small flow rate change cannot be detected, and the reheating operation is performed. However, when this flow switch is used for various other purposes, it cannot be used for applications with a small flow rate, and the device becomes large and expensive.

Further, in the above-mentioned conventional flow switch, since the movement of the magnet provided on the float is detected by the reed switch, it may not be possible to accurately detect it, which may cause a malfunction in a field with a lot of vibration. Will also be.

[0008] Therefore, the present invention provides a small and inexpensive flow switch that can be stably operated without being disturbed by dust in the fluid and can be applied to various fields. With the goal.

[0009]

In order to solve the above-mentioned problems, the present invention provides stoppers above and below a fluid passage having a non-circular surface extending in the axial direction on the inner periphery thereof, and a stopper is provided in the fluid passage between the stoppers. A flow switch is provided by providing a float whose rotation is stopped by the non-circular surface, fixing a magnet on the outer peripheral portion of the float, and providing a Hall IC for detecting the magnetic force of the magnet in correspondence with the moving position of the magnet on the wall of the fluid passage. Is configured.

[0010]

Since the present invention is configured as described above, when the fluid flows in the fluid passage, the resistance raises the float and the magnet provided on the outer peripheral portion of the float also rises. When the flow rate of the fluid exceeds a predetermined value, the magnet rises to a position close to the Hall IC, and the Hall IC detects the magnetic force of the magnet to detect that the fluid has flowed in the fluid passage for a predetermined amount or more. Further, when the flow rate of the fluid decreases, the magnet descends together with the float, and the Hall IC does not detect the magnetic force of the magnet. Therefore, it is detected that the fluid does not flow in the fluid passage for a predetermined amount or more. When moving this float,
Since the outer circumference of the float is stopped by the non-circular surface formed on the inner circumference of the fluid flow path, a sufficient gap can be formed in this part, and dust etc. may adhere to the float etc., resulting in malfunction. To be prevented.

[0011]

Embodiments of the present invention will be described with reference to the drawings. The flow switch 1 includes a main body 3 having a fluid channel 2 therein,
A float 4 inserted in the main body 3 in a loosely fit state, an upper stopper 5 for restricting upward movement of the float 4,
It is composed of a retaining ring of the upper stopper 5 and a Hall IC 8 fixed to a recess 7 formed in the outer wall of the main body 3.

The main body 3 is provided with a float guide portion 11 having a side surface 10 having a quadrangular cross-section and extending parallel to the axial direction of the main body 3 for stopping the rotation of the float, in the middle portion of the inner wall forming the fluid passage. An end surface 12 is formed at an edge portion where each side surface of 11 intersects with a side end surface of a rib of a float described later. A projecting lower stopper 13 is formed at the lower end of the end surface 12, and an upper surface 14 of the lower stopper 13 is an inclined surface that receives a lower end surface of a rib of a float described later. A step portion 15 is formed above the float guide portion 11 and a ring groove 16 is provided on the outer circumference above the float guide portion 11, and an outer peripheral step portion of an upper stopper 5 described later abuts on this step portion, and then the ring 6 is attached. By fitting in the ring groove 16, the upper stopper 5 is prevented from coming off.

The float 4 made of a thermoplastic resin such as DURACON (trademark) is radially extended from the central shaft portion 17 thereof.
The individual ribs 18 are projected, and the thickness of each rib 18 is formed to be equal to or smaller than the width of the end surface 12 of the float guide portion of the main body, and between the side end surfaces 19, 19 of the ribs 18, 18 facing the problem. Is set to be slightly smaller than the distance between the end faces 12 of the float guide portion facing each other. A lower end surface 20 of the float 4 has a circular shape and forms a tapered inclined surface. The upper end surface 21 of the float 4 is curved and is inclined upward toward the center, and a tapered inclined surface is formed also in this portion. The magnet 9 is embedded in one side end surface 19 of the rib 18.

The upper stopper 5 has an annular portion 23, and four stopper pieces 25 extending downward while forming an outer peripheral step portion 24 on the lower side thereof. The lower end of each stopper piece 25 forms an inclined surface 26 corresponding to the inclination of the upper end surface 21 of the rib 18 of the float 4. After inserting the float 4 into the float guide portion 11 of the main body 1, the upper stopper 5
The stopper piece 25 is inserted from above the main body 1 so as to correspond to the end face 12, and the outer peripheral step portion 24 is connected to the step portion 15.
It is set by abutting and then fitting the ring 6 into the ring groove 16.

A hole I is formed in the recess 7 formed on the outer wall of the main body 1.
The plate 28 supporting C8 is press-fitted to fix the tip end surface of the Hall IC 8 in contact with the bottom wall surface of the recess 7.
The lead wire 29 is connected to the Hall IC 8, and the lead wire 29 is provided with a connector 29 '.
Hall IC by connecting the
When 8 detects the magnetic force, the signal is output to the control device. The Hall IC 8 is located at a position slightly higher than the position of the magnet 9 embedded in one of the ribs 18 when the float 4 is inserted into the float guide portion 11 and placed on the upper surface of the lower stopper 13 as described above. Is set to.

With the above structure, when the fluid flows in the fluid passage 2 from the lower side to the upper side in FIG. 2, the float 4 rises and the magnet 9 approaches the Hall IC, so that the Hall IC detects the magnetic force of the magnet. Then, by outputting a signal to the control device, it can be detected that the fluid is flowing in the fluid passage at a predetermined flow rate or more. At this time, each rib 18 is prevented from rotating by the side surface 10 of the float guide portion 11,
Sliding in line contact. Therefore, even if dust is mixed in the fluid and flows, the outer circumference of the float or the float guide portion 11
It operates smoothly without being caught on the inner surface or accumulating. Further, since the taper-shaped inclined surface is formed on the lower end surface of the float 4 and the stopper piece 25, various kinds of dust in the fluid are not caught in this portion as well. On the other hand, when the flow rate of the fluid falls below the predetermined value, the float 4 descends by its own weight and the magnet also descends, so the Hall IC no longer detects the magnetic force of the magnet, and the flow rate of the fluid falls below the predetermined value. Is output to the control device and various related devices are operated. The operating flow rate can be arbitrarily set by incorporating a weight in the float 4.

When the flow switch configured as described above is applied to a bath reheating device, as shown in FIG. 5, the flow switch 1 is provided in a conduit 32 extending from the bath 30 to the circulation pump 31. To do. The output from the Hall IC of the flow switch 1 is input to the control device 33, and the control device 33 outputs the opening / closing control signal of the electromagnetic valve 35 of the bath gas burner 34 in response to the signal. The control device 33 also receives various signals and controls the circulation pump 31 and the additional hot water solenoid valve 36 of the bath.

In the above apparatus, when the circulation pump 31 is operated and the hot water in the bathtub 30 is sucked by the circulation pump 31 through the pipe 32 and flows into the bath heat exchanger 37, the flow switch configured as described above. When a flow of fluid is generated in 1 and the flow resistance of the fluid increases more than the force that supports the total weight of the float, the float 4 rises and the magnet 9 approaches the Hall IC 8, and the Hall IC receives the magnetic force of the magnet 9. Is detected and a signal is output to the control device. The control device 33 opens the solenoid valve 35, supplies gas to the bath gas burner 34, is ignited by the pilot fire, heats and reheats the hot water passing through the bath heat exchanger 37, and the bathtub 30 via the pipe 38. Circulate.

When the operation of the circulation pump 31 is stopped by a signal indicating that the temperature of the hot water in the bathtub 30 exceeds a predetermined temperature, the flow of the fluid in the conduit 32 is stopped. At this time, the flow of the fluid in the flow switch 1 also stops, so the float 4 is placed on the lower stopper 13 by its own weight and returns to its original position.

By providing the above-mentioned flow switch in the bath reheating circuit, when hair or dirt in the bath passes through the flow switch, this flow switch does not have a rotation fulcrum unlike the conventional case. Therefore, hair and dirt do not adhere to and accumulate on the fulcrum of rotation, thus causing malfunction. Further, since the flow path area does not change, the operation is quick and chattering is unlikely to occur.

In addition to the bath reheating circuit, the flow switch having the above-mentioned structure is used for cooling water management of vending machines and computers having a water tank and a pump, and
It can be used for various applications such as an etching apparatus, a diffusion furnace, a CVD apparatus, a resist coating apparatus, and a semiconductor manufacturing apparatus such as a cleaning apparatus.

In the above embodiment, the example in which the four ribs of the float are provided is shown. However, if the number is three or more, any number can be provided, and in that case, the float guide portion also corresponds to the rib. It goes without saying that the shape is changed to a polygonal cross section. Moreover, the number of the stopper pieces 25 of the upper stopper 5 may be one.

[0023]

EFFECTS OF THE INVENTION Since the present invention is constructed and operates as described above, even if various kinds of dust are mixed in the fluid, they are prevented from adhering to and depositing on the flow switch, and the flow switch operates stably. It can be manufactured, can be manufactured in a small size and at low cost, and can be applied to a wide range of fields.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view of an embodiment of the present invention.

FIG. 2 is a sectional view of the same assembled state.

3 is a partial cross-sectional view taken along the line AA of FIG.

FIG. 4 is a partial cross-sectional view taken along the line BB of FIG.

FIG. 5 is a circuit diagram of an embodiment in which the present invention is applied to a bath reheating circuit.

[Explanation of symbols]

 1 Flow Switch 2 Fluid Flow Path 3 Main Body 4 Float 5 Upper Stopper 6 Ring 7 Recess 8 Hall IC 9 Magnet 10 Side 11 Float Guide Part 12 End Face 13 Lower Stopper 14 Top 15 Step 16 Ring Groove 17 Center Shaft 18 Rib 19 Side end face 20 Lower end face 21 Upper end face 23 Annular portion 24 Outer peripheral step portion 25 Stopper piece 26 Sloping surface 28 Plate 29 Lead wire 30 Melting bath 31 Circulation pump 32 Pipeline 33 Controller 34 Bath gas burner 35 Solenoid valve

Claims (5)

[Claims] 1. A stopper is provided above and below a fluid passage formed with a non-circular surface extending in the axial direction on the inner circumference, and a float which is prevented from being rotated by the non-circular surface is provided in the fluid passage between the stoppers. A flow switch, characterized in that a magnet is fixed to, and a Hall IC for detecting the magnetic force of the magnet is provided on the wall of the fluid passage corresponding to the moving position of the magnet. 2. The flow switch according to claim 1, wherein the float is provided with three or more ribs extending radially from its central axis, and the fluid flow path is provided with a non-circular surface corresponding to the shape of the float. 3. The flow switch according to claim 1, wherein an end surface of the float is inclined in a tapered shape. 4. The flow switch according to claim 2, wherein stoppers are provided above and below a position corresponding to the rib of the float in the fluid passage. 5. A magnet is fixed to the outside of the rib of the float,
The flow switch according to claim 2, wherein a Hall IC is provided on the outer wall of the fluid flow path.