JP2768131B2 - Flowmeter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow meter, and more particularly, to a positive displacement flow meter having an explosion-proof structure.

[0002]

2. Description of the Related Art Among flow meters, a flow meter configured to measure a flow rate of a highly flammable fluid such as gasoline and output the detection data as a pulse signal has a strict explosion-proof structure. Has been requested.

For this reason, this type of flow meter is disclosed in
As described in JP-A-136618, a structure is adopted in which the flow meter main body and the transmitter housing are separately formed and then combined integrally, but in such a structure, the device is unnecessarily increased in size. In addition to this, there are various inconveniences such as an increase in manufacturing cost and a difficulty in performing individual inspection of the measuring instrument and the transmitter.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem.
An object of the present invention is to provide an improved flowmeter which can be reduced in size and cost and can be easily disassembled at the time of inspection.

[0005]

SUMMARY OF THE INVENTION The present invention provides a flow meter for achieving the above object, which comprises a lower casing for accommodating a piston sliding in a cylinder, a piston connected to a crankshaft of the piston, and a top portion. A control valve in which one magnet of the magnetic coupling is fixed, an upper casing that accommodates the control valve and has an open top, and is mounted in the opening,
In addition, a partition having a bottomed cylindrical portion that rotatably accommodates a magnet integrated with the encoder is protruded at the center, and the upper casing is confidentially partitioned through the partition and a flow rate pulse is internally transmitted. An explosion-proof casing having an open bottom end for accommodating a vessel, and an encoder disposed in the explosion-proof casing and magnetically coupled to a magnet via a bottomed cylindrical portion.

[0006]

Embodiments of the present invention will be described below. FIG. 1 shows a flow meter according to an embodiment of the present invention.

In this flow meter, a liquid flowing from an inlet 1 is guided to one cylinder 6 via a control valve 2 and a port 5 provided in a valve seat 4, and one piston 7 is moved by the pressure of the fluid. At the same time, the liquid in the other cylinder 6 ′ flows out of the other port 5 ′ through the outflow port of the control valve 2 and the center port 10 of the valve seat 4 from the outflow port 8, and at the same time, the reciprocation of the piston 7 Connecting rod 11
Via a control valve 2 attached to the shaft 9 to sequentially feed the fluid flowing in from the inlet 1 to the next cylinder, and to discharge the fluid from the cylinder to the outlet 8. Further, on the top of the control valve 2, an annular permanent magnet 12, which constitutes one of the magnetic couplings, is held on an outer side by an annular holder 13. It is attached to face the open end.

In the drawing, reference numeral 14 denotes a casing which covers the flow meter. The casing 14 is composed of a casing 17 and an upper casing 17 and a lower casing 16 which accommodate a control chamber 2 for accommodating the piston 7 and a valve chamber 16 for accommodating the control valve 2. The upper casing 18 constituting the valve chamber 16 is further integrally provided with a transmitter housing casing 20 having an open lower end, which constitutes a pressure-resistant explosion-proof chamber 21, with screws 22. .

On the other hand, reference numeral 24 in the figure denotes the upper casing 1.
8 is a partition wall which covers the top open end 19 and divides the valve chamber 16 and the explosion-proof chamber 21 for accommodating the transmitter in a confidential manner.
A thin bottomed cylindrical portion 25 that is inserted into the center hole of the annular magnet 12 provided in the control valve 2 with a small gap is formed integrally with the center portion of the control valve 4 so as to protrude from the lower surface. ing.

The partition wall 25 is formed of an oil-resistant resin material, and is configured such that a bearing 26 attached to a shaft 29 of a rotary encoder 28 can be fixed to a mouth end of the bottomed cylindrical portion 25. The cylindrical magnet 27 fixed to the other end of the rotary encoder 28, that is, the permanent magnet that constitutes the other side of the magnetic joint can be properly supported on the shaft 29 so as to correspond to the above-described annular magnet 12. Reference numeral 35 in the figure denotes an oil sensor for detecting and notifying when oil flows into the explosion-proof chamber 21 due to the disposition of the partition wall 25 or poor sealing from the partition wall 24, and reference numeral 30 denotes a rotary sensor. A mechanical indicator connected to the end of the output shaft 29 of the encoder 28 via a gear 31 and displaying a flow rate counted based on a pulse signal extracted from the rotation of the rotary encoder 28 is a signal output line. It is provided at a separate place (not shown) through the interface 32.

The casing 14 thus constructed is first provided with a top open end 19 of an upper casing 18 thereof.
The partition wall 24 is attached to. As a result, the bottomed cylindrical portion 25 protruding from the lower surface of the central portion of the partition wall 24 fits into the center hole of the annular magnet 12 fixed to the top of the control valve 2. The casing 20 is placed on the top of the upper casing 18.

As a result, the cylindrical magnet 27 is first inserted into the bottomed cylindrical portion 25, and then the shaft 29
Is fixed to the mouth end of the bottomed cylindrical portion 25, and the magnet 27 and the rotary encoder 28
Is a transmitter housing casing 2 constituting the explosion-proof chamber 21.
Fits correctly in 0.

Therefore, when the casing 20 is finally fixed to the top of the upper casing 18 with the screws 22, all the attachments are completed.

In the above, the present invention has been described on the side of the flow meter on which the small mechanical indicator 30 is mounted.
As shown in FIG. 2, it goes without saying that the present invention can be applied to a flow meter having no such indicator 30.

[0015]

As described above, according to the present invention, an open bottom explosion-proof casing containing a flow rate pulse transmitter is fixed to the top of an upper casing containing a control valve via a partition. Therefore, it is not necessary to separately configure the upper casing and the explosion-proof casing, and the apparatus can be configured to be small and inexpensive.

In addition, the partition is provided with a portion for accommodating a magnet integral with the encoder, and this magnet is opposed to the magnet on the control valve side via this portion, so that the upper casing and the explosion-proof casing are airtightly sealed. Despite being a partitioned device, the rotation of the control valve can be reliably transmitted to the pulse transmitter, and at the same time as inspection, etc., transmission to the measuring device is achieved by simply removing the pressure-resistant casing from the top of the upper casing. The instruments can be easily separated and individual inspections can be easily performed.

[Brief description of the drawings]

FIG. 1 is a sectional view of a flow meter showing one embodiment of the present invention.

FIG. 2 is a sectional view of a flow meter showing another embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 2 control valve 12 annular magnet 17 lower casing 18 upper casing 20 pressure-resistant casing 24 partition wall 25 bottomed cylindrical part 27 cylindrical magnet 28 rotary encoder

Claims (1)

(57) [Claims] 1. A lower casing for accommodating a piston that slides in a cylinder, a control valve coupled to a crankshaft of the piston, and having one magnet of a magnetic coupling fixed on a top, and accommodating the control valve. An upper casing having an open top, a partition mounted on the opening, and a bottomed cylindrical portion protruding at the center and rotatably housing a magnet integral with the encoder; and An explosion-proof casing of lower end open type which is sectioned confidentially with respect to the upper casing and accommodates a flow pulse transmitter therein, and which is disposed in the explosion-proof casing and which has a magnet through the bottomed cylindrical portion And an encoder that is magnetically coupled to the flowmeter.