CN2141026Y

CN2141026Y - Alarm for automatic controlling and indicating liquid level

Info

Publication number: CN2141026Y
Application number: CN 92239843
Authority: CN
Inventors: 赵松峰; 李发乐; 张明国; 陈文杰
Original assignee: 赵松年
Priority date: 1992-11-05
Filing date: 1992-11-05
Publication date: 1993-08-25
Anticipated expiration: 2002-11-05

Abstract

The utility model relates to an alarm for automatically controlling and indicating liquid level. The height of the water level in a container is monitored by a liquid level sensor arranged on one side near the steam chamber and the water chamber of the press cap of a water level gauge. The monitor signal is amplified by an amplifying circuit and outputs a signal voltage to a container normal water level control circuit, a super low and high water level alarm circuit, and a water level light display circuit. The utility model uses a liquid level sensor to change a water level signal to an electrical signal and is free from the influence of scale, and accordingly the utility model has the advantages of accuracy and reliability. The water level control, the alarm, and the light display are controlled by a same signal, thus, the light is corresponding to the height of the water level, and the situation of the water level can be clearly displayed through an indicating light.

Description

Alarm for automatic controlling and indicating liquid level

The utility model is automatic control of liquid level display alarms such as a kind of monitoring boiler, pressure vessel and petrochemical industry.

At present, employed water level alarm all is to adopt metal tube or rod to make conductor on the steam boiler, form normally closed, normal open circuit, utilize water can conduct electricity this characteristic, the loop that forms when lack of water or full water is reported to the police the bright bell ring of lamp, but, unsurmountable fatal shortcoming of this water level alarm is that because metal tube or rod contact with high-temperature water or high-temperature steam for a long time, scale and chemical reaction make on metal tube or the rod can tie one deck dirt, time is long more, it is thick more that dirt can be tied, because bird nest is a non-conductor, so use this alarm for a long time, can make water level alarm malfunctioning, therefore can not monitor the truth of boiler middle water level exactly.

The purpose of this utility model provides a kind of safe and reliable, not influenced by incrustation scale, can monitor water level automatically, and self water feeding and cutting off the water, and has the liquid automatic control display alarm of double-colored water-level alarm.

The technical scheme that realizes the utility model purpose is, the gland of the water level meter of installing on boiler is installed a liquid level sensor by the one side in water and vapour chamber, and this sensor is a capacitance type sensor.The output pulse that is produced a fixed-frequency, constant amplitude by a pulse oscillator is added on the capacitance sensor, the linear voltage of capacity of output one and capacitance sensor after filter amplification circuit is amplified, this voltage reduced when water level descended, otherwise increase, control boiler ordinary water level control circuit by the size of this voltage, water level is crossed low and superelevation warning circuit, connects corresponding water level display circuit simultaneously.

Two parallel metallic plates are adopted at the two poles of the earth of capacitance sensor, and the medium between the two-plate is liquid or gas, by what of liquid, and the capacitance of coming the control capacitance sensor.

Fig. 1 is circuit theory diagrams of the present utility model; Fig. 2 is a power circuit diagram; Fig. 3 is installed in front elevation on the liquid level gauge for the utility model; Fig. 4 is the A-A cut-away view of Fig. 2.

The utility model is described in further detail below in conjunction with drawings and Examples.

Gland at liquid level gauge is installed a liquid level sensor by the one side of vapour and water cavity, this sensor is a capacitance type sensor, the two-plate 1 of capacitance sensor Cx adopts two parallel metallic plates to make, medium 2 usefulness liquid between the two-plate 1 or gas are as medium, as shown in Figure 4, when the container middle water level changed, the medium 2 between the two-plate 1 promptly changed, thereby changed the capacitance of capacitor Cx; With pulse oscillator N ₁The fixed-frequency that produces, the output pulse of constant amplitude are added on the capacitance sensor Cx, and the variable signal of capacitance sensor Cx is through diode V ₂, V ₃Rectification is again through resistance R ₅, capacitor C 2 and integrated amplification piece N ₂The filter amplification circuit of group face is amplified back output one and the linear signal voltage Vo1 of capacitance sensor Cx, in order to make output pulse amplitude stable, on oscillating circuit N1, be parallel with Zener diode V1, when water level descends, signal voltage Vo1 reduces, otherwise increases; The integration anti-jamming circuit that signal voltage Vo1 forms by resistance R 6, capacitor C 3 is added to signal the input of comparator N3, N4, N5 and display circuit; Ordinary water level control circuit and water level is low excessively, the superelevation warning circuit in the size of the signal of telecommunication voltage Vo1 control container is connected red, the green light LED that shows the liquid level height simultaneously.

(1) ordinary water level control circuit

The capacity of sensor cx reduces when liquid level descends, and signal voltage Vo1 reduces, and when water level was lower than normal lower limit water level, signal voltage Vo1 was lower than the preset voltage VR of comparator N5 ₃, comparator N5 upset output high-tension electricity Vo2 makes drive circuit K switch 3 closures through current-limiting resistance R9, makes the contactor RL that is connected in the drive circuit ₃The charging pump power supply is connected in adhesive; Voltage Vo2 feeds back to the input of comparator N5 by resistance R 11, R10, produce one and make the out-of-work preset voltage Vo2 ' of charging pump, the capacity of water level rising sensor Cx increases and signal voltage Vo1 is increased, when water level rises to the ULN water level, signal voltage Vo1 is greater than Vo2 ', make comparator N5 upset, voltage Vo2 is a low-voltage by high-voltage variable, K switch ₃Disconnect, charging pump quits work.

(2) water level display circuit

Water level display circuit is the base stage that is added to triode V4 by the signal of signal voltage Vo1, control the one group of indicator lamp LED that is connected on the colelctor electrode by the variation of triode V4 collector voltage Vo5, when water level descends, when signal voltage Vo1 descends, triode V4 collector voltage Vo5 raises, indicator lamp terminal voltage Vo6 is a certain value, thereby the voltage between Vo5 and the Vo6 is reduced, and luminous tube LED working quantity reduces; When up voltage Vo1 rose on the water level, voltage raise between Vo5 and the Vo6, and the luminous tube working quantity increases, thereby makes shinny fluorescent tube LED corresponding with the height of water level, therefore can be clearly from the panel of water level meter from the position of indicator lamp demonstration water outlet.

(3) water level is crossed low warning circuit

Make water level in the container drop to normal lower limit water level also when continuing to descend for a certain reason, will make the capacity of sensor cx continue to reduce, signal voltage Vo1 reduces thereupon, and signal voltage Vo1 is less than the preset voltage VR of comparator N4 ₂, comparator N4 upset, its output voltage V o4 sports high level by low level, makes drive circuit K switch 2 closures by current-limiting resistance R8, makes the alarm RL that is serially connected in this loop ₂Send warning, triode V4 collector voltage Vo5 raises simultaneously, and voltage reduces between Vo5 and the Vo6, and water level is crossed low indicator lamp and become red warning light by original green.

(4) water level superelevation warning circuit

If the water level in the container also continues when arriving the ULN water level to rise, signal voltage Vo1 raises greater than the preset voltage VR1 of comparator N3, comparator N3 overturns, its output voltage V o3 sports high level by low level, make drive circuit K switch 1 closure through current-limiting resistance R7, connect superelevation water level alarm RL1 and send warning, triode V4 collector voltage Vo5 descends simultaneously, voltage superelevation between Vo5 and the Vo6, water level superelevation red led is reported to the police.

(5) power circuit

Power circuit by after the rectifier ZL rectification, is coupled 220 volts of alternating currents as shown in Figure 2 through transformer B, diode V8 and capacitor C 5 rectifying and wave-filterings are low-voltage dc power supply, supplies with each control circuit of this device again after integrated regulator N6 voltage stabilizing.

The utility model does not need liquid as conductor owing to adopted liquid level sensor that water level signal is become the signal of telecommunication, is not afraid of fouling and causes and report to the police malfunctioningly, therefore makes the demonstration precise control, reliable of water level; Water Level Control and warning and light show all by same signal controlling, therefore the startup of charging pump and stop control fully automatically, and light is corresponding with the height of water level, by the situation that can clearly, exactly, directly demonstrate water level on the panel of water level meter from indicator lamp; The utility model is simple in structure, and is with low cost, is present optimal liquid automatic control display alarm.

Claims

1, a kind of liquid automatic control display alarm, it is characterized in that a capacitance level transducer cx being installed on by the one side of vapour and water cavity at the gland of water level meter, the pulse signal that is produced by pulse oscillator N1 is added on the capacitance sensor cx, amplify back output one signal voltage Vo1 through filter amplification circuit N2, again the integration anti-jamming circuit by resistance R 6 and capacitor C 3 compositions signal export container ordinary water level control circuit to, water level is crossed low and superelevation warning circuit and water level lighting display circuit.

2, liquid automatic control display alarm as claimed in claim 1 is characterized in that the two-plate 1 of said capacitance sensor cx is two parallel metallic plates, and the medium 2 between the two-plate 1 is liquid or gas.