GB2251659A

GB2251659A - Fluid pump automatic shut-off control device

Info

Publication number: GB2251659A
Application number: GB9100658A
Authority: GB
Inventors: Tsai-Fu Chang
Original assignee: Individual
Current assignee: Individual
Priority date: 1991-01-11
Filing date: 1991-01-11
Publication date: 1992-07-15
Also published as: GB9100658D0

Abstract

A fluid pump shut down device, preferably for use in a water supply system, includes a housing (21, 22) having a chamber with inlet (23) and outlet (231) ports. A magnetic valve (24) is located within the chamber and is controlled by a bias spring (25) to prevent water flow when water is not being pumped through the supply system. The magnetic valve is moved away from the closed position when water from a water source is pumped by the water pump into the water inlet port (23). The movement of the magnetic valve controls a normally open switch (26) to close the contacts (261) of the switch when the magnetic valve is closed and to energise a heat emitting resistor (27) which in turn heats a bimetal thermostat (28) to deform the contacts thereof, when the water supply is stopped from entering the water inlet port eg when the source is depleted. Opening the contacts of the thermostat disconnects the power supply to the pump. <IMAGE>

Description

FLUID PUMP AUTOMATIC CONTROL DEVICE The present invention relats to a structure of water pump controlling device and more particularly to a water pump idle running automatic shut-off control which automatically cuts off power supply from a water pump which is operated under idle running condition.

In a water supply system, a water pump may be controlled by a water level control switch to start pumping water a water tower at a higher location from a water source at a lower location. The water pump is electrically connected to start pumping when the water level in the water tower is below the predetermined lower limit, or electrically disconnected to stop pumping when the water level in the water tower is over the predetermined upper limit.

However, if there is no water in the water source the water pump may be continuously pumping at idle running when the water level in the water tower is below the predetermined lower limit. The water pump will be damaged very soon when it runs idle. Therefore, the water pump must be frequently checked when it is turned on to pump water.

The present invention has been accomplished under the circumstances in view. It is therefore an object of the present invention to provide a water pump idle running automatic shut-off control which can automatically cut off power supply from a water pump when said water pump is operated under idle running condition. It is another object of the present invention to provide a water pump idle running automatic shut-off control which is easy to install in an existing water supply system.

To achieve the above objects, there is provided a water pump idle running automatic shut-off control which comprises a housing having a magnet valve pressed by a spring coil to constantly block up the water intake port thereof.

When water is pumped into the water intake port by a water pump, the magnet valve is moved from position permitting water to pass therethrough. When water is stopped from entering the water intake pump, the magnet valve is forced by the spring coil to move back, causing a normal opened contact type of solenoid switch to drive a heat emitting resistor to heat a bimetal thermostat to deform so as to disconnect power supply from the water pump.

An embodiment of the present invention will now be described by way of example with reference to the accompanying drawings in which: Fig. 1 is a schematic drawing illustrating the installation of the present invention in a water supply system; Fig. 2 is a sectional assembly view of the preferred embodiment of the water pump idle running automatic shut-off control of the present invention; and Fig. 3 illustrates the control circuit diagram of the present invention.

Referring to the various drawings attached herewith, a detailed description of the structural features of "Water Pump Idle Running Automatic Shut-Off Control" of the present invention is as follows: Referring to Fig. 1, in a water supply system, water from a water source 10 is pumped by a water pump 11 to a water tower 13 through a water supply pipe 12, which water pump 11 is controlled by a water level control switch 14 to start or stop pumping when the level of water in said water tower 13 is below a predetermined lower limit or over a predetermined upper limit. The water pump idle running automatic shut-off control of the present invention is to be mounted in the water supply pipe 12 at a suitable location between the water pump 11 and the water tower 13.

Referring to Fig. 2, the water. pump idle running automatic shut-off control of the present invention is generally comprised of two opposite, water pipe couplings 21 and 22 connected in series and fastened in the water supply pipe 12, defining therein a water intake port 23 at one end and a water outlet port 231 at an opposite end. A magnet valve 24 which is comprised of a magnet covered inside a plastic covering is placed inside the control and pressed by a spring coil 25 to block up the water intake port 23. When water is pumped into the water intake port 23, the magnet valve 24 is moved away from the water intake port 23 permitting water to pass therethrough. When water supply is stopped from entering the water intake port 23, the magnet valve 24 is immediately forced by the tensile force of the spring coil 25 to block up the water intake port 23.There is still a normal opened contact type of solenoid switch 26 fastened inside the pipe coupling 21, a heat emitting resistor 27 and a bimetal thermostat 28 fastened in the outer wall of the pipe coupling 21 and covered inside an outer shell 29.

Referring to Fig. 3, the operation of the water pump idle running automatic shut-off control of the present invention is outlined hereinafter. When water is pumped into the water intake port 23 to move the magnet valve 24 away, the normal opened contact type of solenoid switch 26 is released from the effect of the magnet valve 24, i.e. the solenoid switch 26 returns to its normal open condition and the power suppluy 30 to the load 31 (where the water pump is mounted) is electrically connected through the closed contacts 28 to 282 of the bimetallic thermostat 28. 'hen water is stopped from entering the water intake port 23, the magnet valve 24 is immediately forced by the spring coil 25 to move back to its original position, i.e. the magnet valve 24 returns to the effective position to connect the contact 261 of the normal opened contact type of solenoid switch 26, causing the heat emitting resistor 27 to emit heat at temperature 50to 700C within 30-60 seconds after contact, so as to heat the bimetal thermostat 28 to deform. As soon as the bimetal thermostat 28 is heat to deform, the contacts 281 and 282 of the bimetal thermostat 28 are disconnected from each other, and therefore, power supply 30 is cut off from the load 31. At the same time, an indicator lamp 32 is turned on to give a visual signal. Therefore, the power supply 30 to the water pump at the load 31 will be cut off shortly when no water is pumped into the water intake port 23 during the operation of the water pump.

Therefore there has been described a water pump idle running aiftanatic shut-off control, comprring: a housing comprised of two opposite water pipe couplings connected in series, defining therein a chamber at the middle, a water intake port at one end and a water outlet port at an opposite end; a magnet valve comprised of a magnet covered inside a plastic covering and set inside said chamber; a spring means set inside said chamber to constantly force said magnet valve to block up said water intake port; a normal opened solenoid switch fastened inside said chamber and controlled by said magnet valve to operate; a heat emitting resistor means fastened in said housing at the outside and connected to said normal opened solenoid switch; a bimetal thermostat fastened in said housing and disposed near said heat emitting resistor means, having two contacts normally connected together; and wherein said normal opened solenoid switch is electrically disconnected when water enter said water intake port to move said magnet valve away from position; said normal opened solenoid switch is electrically connected to drive said heat emitting resistor means to emit heat for heating said bimetal thermostat to deform, when water is stopped fram entering said water intake port and said magnet valve is autoanatically forced by said spring means to block up said water intake port, so as to automatically cut off power supply.

Claims

PALMS:

1. A fluid pump autanatic control device for de-energising a fluid pump during idle running thereof, comprising a housing adapted to be connected into a fluid flow system and defining a chamber therein having fluid inlet and Outlet ports; a magnetic valve located within the said chamber to bias the said magnetic valve to close said fluid inlet port; a solenoid switch mounted inside said chamber and operatively controlled by said magnetic valve between a closed position when the magnetic valve is closed and an open position when the magnetic valve is open; heater means mounted on said housing and electrically connected to said solenoid switch; and bimetallic thermostat mounted on said housing and disposed near said heater means, the thermostat having two contacts normally connected together; wherein when fluid is arranged to flow through the control device said magnetic valve is moved to an open position in which the solenoid switch is also open and when fluids stops flowing through the control device the magnetic valve closes the inlet port and operates the solenoid switch to energise the heater means to open the contacts of the thermostat for autanatically disconnecting the power supply to the pump.

2. A control device as claimed in claim 1 wherein the biasing means comprises a compression spring.

3. A fluid automatic control device substantially as hereinbefore described with reference to, and as illustrated in, the accatunying drawings.