GB2287538A

GB2287538A - Water level detector and indicator system

Info

Publication number: GB2287538A
Application number: GB9404751A
Authority: GB
Inventors: Ping-Shin Wang
Original assignee: Pai Lung Machinery Mill Co Ltd
Current assignee: Pai Lung Machinery Mill Co Ltd
Priority date: 1994-03-10
Filing date: 1994-03-10
Publication date: 1995-09-20
Anticipated expiration: 2014-03-10
Also published as: HK1004292A1; GB9404751D0; GB2287538B

Abstract

A water level detector and indicator system includes a water level detector and a water level display controlled by the water level detector to give a respective output signal when the level of water changes from one position to another. The water level detector may be a mechanical type which uses a float 1 to control a multi-step switch mounted within a casing 5 and causing a series of indicator lamps 4 to give light respectively. The water level detector can be an electronic type (Figs 6 - 9) which uses metal probes to detect the change of water level, and a controller driven by the metal probes to control buzzers and indicator lamps. A modification of the Fig 1 embodiment (Figs 4 and 5) comprises a plurality of casings, each with its own float arm, at different heights. <IMAGE>

Description

WATER LEVEL DETECTOR AND INDICATOR SYSTEM The present invention relates to a water level detector and indicator system which shows the water level of a water reservoir step by step so that the users have sufficient time to take the necessary steps before the water reservoir is empty.

A water reservoir may be installed in a building for keeping water. When a water reservoir is installed, it must be properly sealed to prevent contamination. Once a water reservoir is sealed. it is difficult to know the existing amount of water contained in the water reservoir. In order to keep water be continuously and automatically supplied, a switch is common installed to control the water pump permitting it to pump water to the water reservoir when the level of water drops below the predetermined range.

However, if the external water supply to the water reservoir is stopped, the water pump will run in idle when the level of water drops below the predetermined range. and the users can know the situation only when water in the water reservoir has been completely used up. One object of the present invention is to provide a water level detector and indicator system which indicates the changes of water level in the water reservoir through indicator lamps by means of the operation of a float-controlled switch. Another object of the present invention is to provide a water level detector and indicator system which gives an alarm signal to the end-users when the level o.

water in the water reservoir drops below t;.e predetermined alarm rane.

The present inven tion ill ncw ne described by way of examples only with reference to the annexed drawings, in which: Fi. 1 shows a first mecrianical water level detector and indicator system according to the present invention Fig. 2 shows the first mechanical water level detector and indicator system of Figure 1 installed in the water reservoir; Fig. 3 shows the first mechanical water level detector and indicator system of Figure ' operated when the level of water changed; Fig. 4 shows a second mechanical water level detector and indicator system according to the present invention;; Fig. 5 shows the second mechanical water level detector and indicator system of Figure 4 installed in the water reservoir; Fig. 6 is a block diagram of an electronic type water level detector and indicator system according to the present invention: Fig. ' is a partial circuit diagram for the electronic type water level detector and indicator system shown in Figure 6, showing the control of the water level detector and the motor: Fig. 8 is another partial circuIt diagram for the electronic type water level detector and indicator system shown in Figure 6 showing the encoding procedure of the detected signal; and Fig. 9 is still another partial circuit diagram for the electronic type water level detector and indicator system shown in Figure 6, showing the decoding procedure and the output of the buzzer and display.

Referring to Fig. 1, therein illustrated is a first mechanical water level detector and indicator system according to the present invention, which is generally comprised of a float 1. a float arm 2, a switch 3, and a pluraiiv- ef indicator lamps 4. The float 1 is fastened to the float arm 2 at one end. The opposite and of the float arm 2 is perpendicularly connected to a revolving shaft 3l on the switch 3. Therefore.

the shaft 31 is turned as the float 1 is lowered.

The switch 3 zomprises a circular base 32 mounted on the shaft 31 by a bearin, having a plurality of switching points 321 on one side thereof around the border. The shaft 31 has one end coupled to the float arm 2, and an opposite end revolvably fastened to the circular base 32 of the switch 3 at the center by a bearing and coupled with a contact 33 at right angles. The switch 3 is received inside a water-proof casing 5. The indicator lamps 4 are respectively connected to either switching point 321 on the circular base 32 of the switch 3 by a respective electric wire for indicating a corresponding water level.

Referring to Fig. 2, the casing 3 is fastened to the inside wall of a water reservoir 6 at a suitable elevation, preferably at the full water level. As the water level drops. the float 1 is lowered to turn the float arm 2 downwards, and the contact 33 of the revolving shaft 31 is moved to pass over the switching points 321 from one to another in triggering the corresponding indicator lamps 41. During the full water level stage.

the contact 3 contacts the lowest switching point causing the corresponding indicator lamp 41 to give light. As the water level drops, the contact 321 is turned upwards to contact the next switching point, and the next indicator lamp 4' is turned on.

Therefore, the user can know the current water level in the water reservoir 6 according to the indicator lamp being turned on. The contact 33 is made in the shape of a sector constantly maintained to contact either switching point, i.e.

the contact 33 keeps in contact with one switching point 321 before it is moved to contact the next switching point 322, therefore there is always a corresponding indicator lamp being turned on.

This arrangement eliminates possible vacant interval. Further. the casing 5 has a stop bar 51 disposed below the revolving shaft 31 to limit the down stroke of the float arm 2. If the float arm 2 is turned downwards to the vertical position, it will become stuck when the water reservoir is refilled to the full water level again. The arrangement of the stop bar 51 eliminates this problem.

Referring to Fig. 3, therein illustrated is an operational view showing the operation of the first mechanical water level detector and indicator system at different water levels.

Referring to Figs. 4 and 5, therein illustrated is a second mechanical water level detector and indicator system of the present invention. As illustrated, several casinos are respectively fastened to the inside wall of the water reservoir 6 at different elevations. Each casing comprises a revolving shaft 9 driven by a respective float arm 91 to turn a respective contact 92, and a switching point -1. '', ..., or connected to a respective indicator lamp 81. 82.

..... . . . q or 85. When at the full water level. the float arm 91 of the casing at the top is floated upwards to disconnect the contact 92 from the respective switching point 71, and therefore the corresponding indicator lamp 81 is turned off.

If the water level falls below the casing 7 at the top, the float arm 91 is lowered, causing contact of the contact 92 with the switching point 71 in the respective casing , and therefore the corresponding indicator lamp 81 is turned on to give light. In the same manner, the next indicator lamp 82 will be turned on as the water level drops below the next casing. When the indicator lamps 81, 32, . . ., 85 are all turned on, it shows that the water level has been dropped below the predetermined alarm range. On the contrary, the indicator lamps will be turned off one after another as the water level of the water reservoir is increased from the low water level to the high water level.

As indicated, when the water level drops below the predetermined water level causing the first indicator lamp 41;81. the water pump of the water reservoir will be automatically turned on to pump water to the water reservoir. When the water level surpasses the predetermined water level, the first indicator lamp l1;81 will be turned off again. If the first indicator lamp 41;81 keeps giving light or the next indicator lamp 42;82 is turned on under this stage, it means that the motor was damaged or the supply of water was stopped. If the motor was damaged, it should be quickly repaired. In case the supply of water was stopped, the motor should be immediately turned off to prevent idle running.Furthermore, the length of the float arm 2 may be made adjustable: the number of switching points 321 may be determined according to the capacity of the water reservoir.

Referring to Figures 6 and 7, a water level detector and indicator system of the present invention can be an electronic type. The water level of the water reservoir is detected by a water level detector 10. The water level detector 10 comprises a plurality of metal probes 100 disposed in the water reservoir at different elevations to detect different levels of water, and a plurality of amplifiers 101 to amplify the signal from either metal probe 100. The signal from either amplifier 101 of the water level detector 10 is then treated through a filter 11 to remove noises. The output signal from the filter 11 is sent to a switch control 12 and an encoder 14 respectively. The switch control 1 automatically turns on a motor 13, upon receipt of the signal from the filter 11, causing it to pump water to the water reservoir.

By means of the priority control of a logic circuit 121, the motor 13 can be turned on manually through a manual switch SW-1 or turned off manually through a manual switch SW-2. Therefore, the motor 13 can be turned off manually to prevent idle running when there is no water supply. Further. the DC power supply circuit 102, as shown in Figure -, provides the electronic type water level detector and indicator system with the necessary working voltage.

Referring to Figures 8 and 9 and Figure 6 again, the encoder 14 puts the signal from the filter 11 into a four-bit code and then sends it to the end-users. The encoder 14 also receives the output control signal from a buzzer and display controller I. The buzzer and display controller 15 is comprised of time control IC 4541 US, 9, U10, capacitors C1,C2,C3 and variable resistors VR1, VR- , VR-3 for controlling charging and discharging time so that the alternative operation of the buzzer and display circuit 17, 17' (see Figure 9) is controlled. The time control IC US controls the flashing cycle of the display 171; the time control IC U9 controls the time of buzzing of the buzzer 172.The alternative operation of the buzzer 172 and the display 171 is controlled by the time control IC U10. When the water level of the water reservoir drops below the predetermined alarm range, either amplifier AMP-4 or ANIP-9 (see Figure ,) gives an output signal causing the display 1'1 and the buzzer 172 to work.

Referring to Figures 6 and 9 again. the four-bit code of the output of the encoder 14 is sent to the end-users through a bus line BUS 140.

Decoders 16,16' and buzzer and display circuits 17,17' are installed in the end-users. The decoders 16,16' decodes the signal from the encoder 14 for driving the buzzer and display circuits 17,17'. The display 11 consists of a plurality of light emitting diodes respectively connected to the aforesaid metal probes leo0. The measure of encoding the detected signal and then decoding it for output is to improve signal transmission efficiency. The arrangement of the bus line is for equivalent signal output to all end-users in the most efficient way.

While only few embodiments of the present invention have been shown and described. it will be understood that various modifications and changes could be made without departing from the spirit and scope of the invention.

Claims

CLAIMS:

1. A water level detector and indicator system comprising: a water tight casing disposed inside a water reservoir in the full water level position; a switch received inside said watertight casing, said switch comprising a rotatable shaft extended through a hole on said casing, a circular base received inside said watertight casing and mounted on said rotatable shaft by a bearing, said circular base having a plurality of switch points on one side thereof around said rotatable shaft, said rotatable shaft having a metal contact at one end and disposed in contact with one of the switch points on said circular base; a float arranged to float in water in the reservoir and having a float arm connected to and extending radially from said rotatable shaft of said switch; a plurality of indicator lamps respectively connected to either switch point on said circular base and being alternately triggered to give light as said metal contact moves by said float through said rotatable shaft from one switch point to another following a change of water level in said water reservoir.

2. The water level detector and indicator system of claim 1 wherein said watertight casing comprises a stop bar on the outside to limit the down stroke of said float arm from being moved to vertical.

3. A water level detector and indicator system comprising: a plurality of water tight casings respectively disposed inside a water reservoir at different elevations, each casing comprising a switch point on the inside, a rotatable shaft having a front end terminating in metal contact turned to contact the respective switch points of the casing and a rear end extending outwardly of the casing, and a float having a float arm extending radially from and connected to the rear end of the rotatable shaft; and a plurality of indicator lamps respectively connected to a switch point and contact of either casing and being triggered respectively to give light when the respective contact of the casing is moved by the respective float to contact the respective switch point.

4. A water level detector and indicator system comprising: a plurality of metal probes disposed inside a water reservoir at different elevations to detect the level of water in said water reservoir; a water level detector circuit having a plurality of amplifiers equivalent to the number of probes to amplify a detected signal from a respective one of the metal probes and to provide a corresponding output signal therefrom; a buzzer and display controller for receiving the output signal of said water level detector circuit and then to provide a control signal; a filter to receive the output signal of said water level detector circuit and to provide an output signal therefrom; a switch controller arranged to receive the output signal of said filter, said switch controller comprising a manual control switch and a logic circuit for determining the priority of the output signal of said filter and said manual control switch; an encoder for receiving the output signal of said filter and the control signal of said buzzer and display controller; at least one decoder to decode an output signal from said encoder; and a buzzer and display circuit having at least one buzzer and at least one display controllable by said at least one decoder to give an audio output signal and a visual output signal respectively.

5. The water level detector and indicator system of claim 4 wherein said filter consists of a plurality of filter ICs to remove noises from the detected signal.

6. The water level detector and indicator system of claim 4 wherein said logic circuit determines the priority of the output signal of said manual control switch over the output signal of said filter.

7. The water level detector and indicator system of claim 4 wherein said at least one display respectively consists of a plurality of light emitting diodes in number equal to said metal probes.

8. A water level detector and indicator system substantially as hereinbefore described, and as illustrated in, Figures 1, 2 and 3, Figures 4 and 5, or Figures 6, 7, 8 and 9 of the accompanying drawings.