JPH0128411Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flow rate detector for automatically controlling related equipment by detecting the flow rate of fluid, especially water, and sending an electrical signal.

Conventionally, in order to detect the flow rate of a fluid, a rotary impeller with a magnet attached is placed in the fluid flow path, and the rotation speed of this magnet is detected by a magnetic sensor such as a Hall element. Even when the flow stopped, the impeller continued to rotate due to inertia for a while, and it took some time for it to stop completely. Therefore, this type of flow rate detector is incorporated into a proportional control instantaneous water heater that changes the amount of combustion gas in response to changes in water flow rate and maintains a constant outlet temperature. If it is also used as a water flow switch to detect water flow, if there is a delay in stopping as described above, even though the water flow has been stopped, combustion will continue for a while assuming that there is water flow, resulting in a state of half-dry firing. There was an inconvenience.

The present invention was developed with the aim of eliminating such inconveniences, and is capable of extremely shortening the time from the stop of water flow to the stop of the impeller.An example of the invention will be described below with reference to the drawings. .

1 is a bottomed cylindrical flow rate detector body with an inlet 2 and an outlet 3 opened eccentrically from the center on the side wall; 4 is an impeller rotatably housed in the detector body 1; It consists of a shaft portion 5 and a large number of blades 6 provided around the shaft portion 5. The shaft portion 5 is provided with a hollow shaft hole 7 that opens at the bottom, and the hollow shaft hole 7 is inserted into a pin-shaped bearing 9 implanted in the center of a lid 8 that closes the bottom of the flow rate detector main body 1. It's starting to become easier. The upper end of the shaft portion 5 extends upward through the spacer 10, and is sharpened into a needle-like or round-head shape, and a permanent magnet 11 is attached around the upper end. The bearing 9 is provided with a braking surface 13 that faces the bottom surface 12 of the shaft section 5 of the impeller 4, and when the shaft section 5 is stopped, the bottom surface 12 of the shaft section 5 touches the braking surface 13.
I try to ride it face to face. This braking surface 13
Of course, it is also possible to protrude integrally from the upper surface of the lid body 8. Further, a slight gap 15 is provided between the upper end of the shaft portion 5 and the upper bottom surface 14 of the main body 1, so that the impeller 4 can move up and down. The blades 6 are formed radially around the shaft portion 5 at equal intervals and oblique to the water flow direction so that each blade 6 receives water pressure and generates a force that pushes the entire impeller 4 upward. be. Reference numeral 16 denotes a magnetic sensor such as a Hall element mounted on the upper surface of the main body 1, which receives changes in the magnetic field caused by the rotation of the magnet 11 and emits pulses according to the rotation speed.

In this configuration, when a water flow occurs, the impeller 4 starts to rotate due to the water flow, but since the blades 6 are provided diagonally, the water flow pressure partially changes into a force that pushes up the entire impeller 4, and the impeller 4 starts to rotate. floats up while rotating, and continues to rotate with the upper end of the shaft portion 5 hitting the bottom surface of the upper part of the main body. This rotational speed changes in proportion to the flow rate, and the magnetic sensor 16 detects the current flow rate and converts it into an electrical signal. Next, in the case of a water heater, the water flow is stopped by closing the hot water supply door, but when this water flow is stopped, the impeller 4 tends to continue rotating due to inertia. However, in this case, since the blades 6 are provided diagonally, the water stopped in the main body 1 acts as resistance pushing down the impeller 4 via the blades 6, and the impeller 4 instantly descends, causing the bottom surface 12 of the shaft portion 5 to fall.
slides against the braking surface 13, creating frictional resistance,
The impeller 4 is braked and immediately stops.

Therefore, even in a water heater in which the rotation of the impeller 4 is linked to combustion, boiling or half-empty heating does not occur due to the fact that it takes some time to extinguish the water even when the water is turned off.

It goes without saying that the present invention has similar effects on gas flow rate detection.

As described above, the present invention provides an impeller equipped with a large number of blades that rotates due to the flow in a fluid flow path, and detects the rotation of a permanent magnet interlocking with the impeller using a magnetic sensor. The impeller is provided so as to be movable in the direction of its rotational axis, and the blades provided on the impeller are provided diagonally to the flow direction, so that when the fluid stops, the resistance of the stopped fluid causes the entire impeller to act as a flow rate detector. The impeller is created by generating force in the direction of pressing against a braking surface fixedly provided on the main body, etc., and braking the impeller by frictional resistance with this braking surface, so when the fluid flow stops, The impeller stops immediately without any delay, and an extremely excellent flow rate detector that does not cause an afterburn phenomenon can be obtained, especially when used in water heaters.

Therefore, when this is used in a proportional control instantaneous water heater, there is no need to provide a separate water flow switch to detect the presence or absence of water flow in addition to the conventional flow rate detector, which greatly contributes to cost reduction. .

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, with FIG. 1 being a longitudinal cross-sectional view of the entire structure, and FIG. 2 being a side view of the impeller. 1...Flow rate detector body, 4...Impeller, 6...
Blade, 11... Permanent magnet, 13... Braking surface, 16
...Magnetic sensor.

Claims (1)

[Scope of utility model registration request] An impeller equipped with a large number of blades that rotates with the flow of fluid is provided in a fluid flow path, and a magnetic sensor detects the rotation of a permanent magnet interlocking with the impeller. Set up movably,
A braking surface that faces and contacts the bottom surface of the shaft of the impeller is provided on the flow rate detector main body side, and the blades provided on the impeller are provided diagonally to the flow direction, so that when the fluid stops, the damping surface of the stopped fluid is A flow rate detector characterized in that a force is generated in the direction of pressing the entire impeller against the braking surface by resistance, and the impeller is braked by frictional resistance with the braking surface.