JPS59229626A - Floatless liquid level relay - Google Patents

Abstract

PURPOSE:To prevent incorrect display and malfunction by connecting a delay circuit to be actuated at the connection of a power supply between a liquid surface detecting circuit and an output relay circuit. CONSTITUTION:A load circuit such as a light emitting diode LED4 in the output relay circuit CR3 is driven by detecting signals from the liquid level detecting circuit BD'2 and a switch SW. At the connection of the power supply, a delay circuit TM for holding a switching element Q1 at OFF status for a prescribed period is connected to the output relay CR3. In case of detection of a water level, a thyristor SCR3 is disconnected at the rise of the water level in a water tank, so that a light emitting element in a photocoupler PC is turned off. Consequently, the switching element Q1 is turned on, a relay RY3 is excited and a light emitting diode LED4 is turned on. Although the thyristor SCR3 is disconnected immediately after turning on the power supply, voltage application to the switching element Q1 is delayed by the delay circuit TM and incorrect display is not generated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a floatless liquid level relay for detecting the liquid level in a water tank, controlling a pump, and issuing a full-water or water-drought alarm.

[Background technology]

In the conventional water level control device, when the power switches I A and IB are turned on, a voltage of AC 200 V is applied, the floatless liquid level relay 2 becomes operable, the changeover switch 3 is set to the "auto" position, and the changeover switch 4 is turned on. When it is set to the "self-crossing" position, the automatic alternate operation relay 5 becomes capable of automatic alternate operation.

When the water level of the water tank 6 is less than L2, the electrode E in the water tank 6.

, E□, E2 are above the water surface, and the electrodes Eo-
No current flows between E2 and floatless liquid level relay 2.
does not output voltage from terminal TA, and NOI and NO2
All drainage pumps (not shown) have stopped operating.

The water level in water tank 6 due to water supply exceeds L2, and electrode E3°83
Even if a current flows between them, the duration is less than L
The operation of the O2 drainage pump continues to be stopped. / After that, the water level of the water tank 6 exceeds the L height and the electrode E3. When current flows through the E terminal, the floatless liquid level relay 2 outputs the luminous pressure from the terminal TA, and this voltage is input to the automatic alternating operation relay 5 through the changeover switches 3 and 4, which outputs voltage to the terminal T, for example. operation of the NOI sump pump (not shown) via the stain magnetic contactor (not shown) by energizing the relay 7 and turning on its first a contact (not shown). is started to drain water from the water tank 6, and at the same time, the relay 7 is energized to turn on the ON operation indicator lamp 8 of the second one contact 7a to indicate the operation of the NOI drainage pump.

After that, the water in the water tank 6 decreases and the water level becomes less than (), and if current no longer flows between the electrodes E3 and E1, the NOI drainage pump continues to operate for a period of 2 or more.

That guy, the water level in the water tank 6 is less than 12 and the electrode E3゜E
When current no longer flows between terminals 2 and 2, the voltage output from terminal TA disappears, automatic alternating operation relay 5 stops energizing relay 7, turns off the first a contact, and stops the operation of the NOI drainage pump. At the same time, the second a contact 7m is turned off to turn off the operation indicator lamp 8. At this time, the automatic alternate operation relay 5 switches the switching contact of the latching relay (not shown) to the terminal T of the floatless liquid level relay 2.
Preparations are made to output voltage from terminal T2 when voltage is output from terminal A.

Thereafter, even if the water level in the water tank 6 exceeds L2 again due to water supply, the stopped state continues as long as it is less than L□.

After that, when the water level of the water [6 exceeds L□, voltage is output again from the terminal TA, and this voltage is applied to the automatic alternating operation relay 5 via the changeover switch 3.4 in the same way as above.
A voltage is generated at the terminal T to excite the relay 9, and the first
By turning on the a contact (not shown), the operation of the NO2 drainage pump (not shown) is started via the electromagnetic contactor (not shown) to drain water from the water tank 6, and at the same time, the relay 9 is turned on.
When the second 8 contacts 9m are turned on by the excitation, the operation display lamp 10 is turned on to display the entire operation of the NO2 drainage pump.

Thereafter, the water in the water tank 6 decreases and the water level reaches L0-i, and the NO2 drainage pump continues to operate for a period of 2 or more.

After that, when the water level in the water tank 6 becomes less than 3, the voltage output from the terminal TA disappears, the automatic alternate operation relay 5 stops excitation of the relay 9, turns off the first a contact, and turns off the NO2
The operation of the drainage pump is stopped and the second 8 contacts 9
a to turn off the operation indicator lamp 10. At this time, when the switching contact of the latching relay is reversed and voltage is output from the terminal TA of the floatless liquid level relay 2, the automatic alternate operation relay 5 prepares the terminal T to output the stain pressure. do.

After that, the operation from the beginning will be repeated.

Now, for example, while the NOI drainage pump is draining water from the water tank 6 according to instructions from the floatless liquid level relay 2 and the automatic alternating operation relay 5, due to some abnormality, the NOI drainage pump has stopped. In this case, the water level in the water tank 6 would rise rapidly due to no drainage operation, and the water level would exceed the water level L, and the water level would rise further. It will also exceed. As a result, no current flows between the electrodes E31 and EO, and the floatless liquid level relay 2 outputs a voltage from the terminal LL, the full water indicator lamp 11 lights up, and the relay 2 is energized. Due to the excitation of this relay 12, its first eight contacts 128 are turned on, and the simultaneous operation state is not established.The voltage from the terminal T of the automatic alternate operation relay 5 energizes the relay 9, and its first three contacts are turned on. When the NO2 drain pump (D operation is started and the second 8 contacts 98f) is turned on via the magnetic contactor, the operation indicator lamp 10 lights up. In addition, due to the excitation of the relay 9, its second 8 contacts 12b are turned on, and the voltage from the terminal TA of the faceless liquid level relay 2 (which is always output when the water rises abnormally) is also adjusted to the relay 12. Even if the water level in the water tank 6 drops to Lo υ due to the operation of the NO2 drainage pump and the voltage from the terminal LL disappears, the NO2 drainage pump continues to operate and the full water indicator lamp 11 lights up. I have to. In addition, due to the drainage operation of the NO2 drainage pump, water is removed to 1il (the water level in i is L2).
When the voltage drops below , the voltage from the terminal TA of the floatless liquid level relay 2 disappears, and the excitation of the relay 12 stops.
The first A contact 12m is turned off, and the automatic alternate operation relay 5 also outputs no voltage from the terminal T (fi5.N
The operation of the O2 drainage pump ° is stopped, and the full water indicator lamp 11 is also turned off. Note that when the NO2 drainage pump is out of order, the NOl drainage pump will operate.

Next, set the selector switch 4 to l'-NOIJ or "N0
When switched to 2J, automatic alternate operation relay 5 does not operate,
The circuit system consisting only of the NOI or NO2 drainage pump operates in accordance with the output of the floatless liquid level relay 2. In addition, when the changeover switch 3 is switched to "test", NOI
It is possible to perform an operation test of automatic alternate operation and single operation of the drainage pump (2).

Next, the specific structure and operation of the floatless liquid level relay 2 in the water level control device will be explained based on FIG. 2. This floatless liquid level relay 2 connects the AC 200V power supply voltage to terminal S. I have input from between 182 and 182. The input AC200V power supply voltage is applied to the primary winding PT of the power transformer PT, and the secondary winding PT2a, PT2
b, PT2o! 7AC12V, AC24V.

The power supply voltage of 24V AC is taken out from IA.

Secondary winding PT2. The AC 12V power supply voltage output from the floatless liquid level relay 2 is the main power supply voltage, and the application of the main power supply voltage is displayed by the power supply display circuit CX. Specifically, the application of the main power supply voltage is indicated by the light emitting diode LED□ via the diode bridge DB. The C part is a smoothing capacitor, and the R part is a current limiting resistor.

In addition, the AC 24V power supply voltage output from the secondary winding PT2b of the power transformer PT is applied to the control water level detection bridge circuit BD, and the secondary winding PT2b of the power transformer FT
The AC 24V power supply voltage output from 2° is applied to the water level detection bridge circuit BD2 for full water alarm. The control water level detection bridge circuit BD□ is composed of resistors R2 to R7 and the agricultural contact ry of the relay RY, and the water level detection glitch circuit BD2 for full water alarm is composed of the resistors R8 to R and the relay RY. It is composed of a contact point ry2a.

Control output relay circuit CR construction consists of thyristor SCR□, relay RY construction, resistor R□3' R14, and capacitor C.
2゜C3, diode D construction, light emitting diode LED construction for relay operation display, output relay circuit CR construction for full water alarm, thyristor 5CR2, relay RY, and resistor R construction.

R-engineer. It consists of capacitors C4 and C5, a diode D2, and a light emitting diode D2 for indicating relay operation. In the thyristor SCR construction, when the potential of the X2 point of the control water level detection bridge circuit BD□ is higher than the potential of the Turn on ryla and turn on b contact ry
Turn off lb. In thyristor 5CR2, when the potential at point Y0 of the water level detection bridge circuit BD2 for full water alarm is higher than the potential at point 72, a current flows between the gate and cathode and conducts, energizing relay RY2 and turning on its a contact ry2a. At the same time, the b contact ryzbtry2c is turned off.

2-z3 is an arrester, and z4 is a varistor.

Next, the operation will be explained in detail.

When the water level in the water tank 6 is less than 12, the connection between the electrode E3 and the electrode is in an open state, and the resistance value therebetween is infinite.
The potential at the point is higher than the potential at point is excited,
The b contact 'yxb is turned off, and no voltage is output from the terminal TA. Further, the energization of the relay RY□ turns on the 8th contact ry1a, shortens the resistor R5, and lowers the potential at the point X2.

When the water level in the water tank 6 exceeds R2, the electrode E3 and the electrode E2
A current flows between them, and the potential at one point rises a little, but the potential at point X is still higher, so current flows from point X to point , thyristor SCR continue to be conductive, therefore relay RY continues to be energized, and no voltage is output from terminal TA.

When the water level in the water tank 6 exceeds L□, a current flows between the electrode E3 and the electrode E, and the potential at the point
The potential of the two points becomes higher than the potential of the X0 point, and as a result, the gate current no longer flows through the thyristor SCR, the thyristor SCR□ is cut off, the light emitting diode LED2 goes out, and the excitation of the relay RY stops. b contact rylb
When is off, voltage is output from terminal TA. At this time, the a-contact ryla is turned off at the same time, so that the short termination of the resistor R5 is canceled and the potential at the point X3 rises.

After this, when the water level in the water tank 6 drops by L Since the voltage is also high, the thyristor 5CR1 continues to be cut off, and therefore the relay RY□ is not energized either, and voltage continues to be output from the terminal TA.

When the water level in the water [6 further decreases below L2, the gap between electrode E3 and electrode E is opened, the potential at point X2 further decreases, and the potential at point X0 becomes lower than the potential at point X2. and return to the initial state.

Next, the water level in tank 6 will rise. When less than, electrode E3
and electrode E. is in an open state and the resistance value between them is infinite. In the detection bridge circuit BD2 for full water alarm, the potential at point Y0 is higher than the potential at point 72, and the potential from point Y0 to the gate/cathode of thyristor 5cR2 is through 7
Current flows to two points, the thyristor 5cR2 conducts, the light emitting diode LED3 lights up, the relay RY is excited, and the seventh B contact ry2b is turned off, so no voltage is output from the terminal LL. Further, the stain contact ry2a is turned on by the excitation m, the resistor R1o is short-circuited, and the potential at point 72 is slightly lowered.

The water level in tank 6 has risen. When the electrode E3 and the electrode Eo exceed
As a result, current flows between the thyristor 5CR2K and the thyristor 5CR2K, and the light emitting diode LEDrS turns off. , and relay RY
2 stops excitation, b contact 'Y 2b turns off, and 1! from terminal LL! Pressure is no longer output.

At this time, the a contact ry2a is turned on at the same time, and the potential at the 72 points rises slightly.

A certain amount of hysteresis is added to the conduction/cutoff of the on/off thyristor 5CR2 of the 8 contacts ry2PL of the relay RY2, thereby preventing chattering due to waves on the water surface.

As described above, in the conventional floatless liquid level relay 2, the output relay contact of the full water alarm output relay circuit CR2 for the full water alarm is the b contact. On the other hand, in the case of a water shortage alarm, the a contact may be used as the output relay contact of the same output relay circuit CR2. In some cases, the output relay contact for a full water alarm is an A contact, and the output relay contact for a low water alarm is a B contact.

However, in such a conventional example, when a b contact is used for an alarm, there is a risk that an erroneous display may occur or a malfunction may occur.

For example, in the case of the floatless liquid level relay 2 shown in Fig. 2,
A B contact is used as the output relay contact for the full water alarm, but when a B contact is used in this way, the output relay becomes de-energized during a power outage, resulting in a full water display (erroneous display) even though the water is not full. There's a problem. In addition, when this floatless liquid level relay 2 is incorporated into a water level control device as shown in Fig. 1, when the water level control device is powered on, the output relay's b contact is not yet separated, so the simultaneous operation circuit is disabled. There is a problem of self-retention (malfunction).

[Purpose of the invention]

An object of the present invention is to provide a floatless liquid level relay that can prevent erroneous display and malfunction.

[Disclosure of the invention]

The floatless liquid level relay of the present invention includes a liquid level detection circuit that turns on and off a first switch element in response to the height (or low and high) of the liquid level; 8 contacts of the output relay are turned off by turning off the second switch element, and the second switch element r>'+J is turned on in response to turning off the first switch element. an output relay circuit that turns on three contacts of the output relay; a load circuit that responds to turning on of the eight contacts of the output relay; and (b) an output relay circuit that delays turning on and off of the first switching element. The configuration includes a delay circuit for transmitting the signal, thereby preventing malfunctions when the power is turned on, turned off, or during a power outage. Note that the load circuit includes an alarm circuit, a liquid level control circuit, and the like.

Next, one embodiment of the present invention will be described based on FIGS. 3 and 4. This floatless liquid level relay 2' is
Power transformer FT, control water level detection bridge circuit BD□
, control output relay circuit CR and power supply display circuit CX
The details are the same as in Figure 2.

The water level detection circuit BIy2 for the full water pipe layer has resistors R8 to R.

. It is composed of R□2.

The switching circuit SW for full water f1 notification is thyristor 5C.
R3 and resistance R□7~R work. , capacitors c6 to c8, and diode D3. Thyristor 5cR3 is composed of D4 and a photocapri PC light emitting element, and when the potential at point Y0 of the water level detection bridge circuit BIy'2 for full water alarm is higher than the potential at point 72, a current flows between the gate and the cathode and the thyristor 5cR3 becomes conductive. Then, electricity is applied to the light emitting element of the photocoupler PC to cause it to emit light.

The full water alarm output relay circuit CR3 consists of a transistor and a resistor R2 that provides a base voltage to the transistor Q□.
0I R2□ and the relay RY3 connected in series to the transistor resistor, the light emitting diode LED4 for indicating full water connected in parallel to the relay RY3, the resistor R22 for its limit cape, the photocoupler connected between the diode D5 and the base φ emitter of the transistor Q1. It is composed of a PC light receiving element. ry3b l 'Y 3c is the b contact of relay RY3.

The delay circuit (integrator circuit) TM is composed of resistors R23-R24, a capacitor C0, and a diode D6, and is configured to delay the application of a base voltage to the transistor circuit for a certain period of time when ti is on.

Next, the operation of this circuit will be explained in detail. The water level in tank 6 has risen. When less than, electrode E3 and electrode E.

is in an open state and the resistance value between them is infinite. In the water level detection bridge circuit BD'2 for full water alarm, the potential at the Y0 point is higher than the potential at the 72nd point, and from the Y0 point the thyristor A current flows through the gate and cathode of 5CR3 to point 72, thyristor 5CR3 becomes conductive, and the light emitting element of the photocoupler PC lights up.Therefore, the base and emitter of the transistor are shorted, and the transistor Q is turned off. , relay RY3 is not excited and a contact ry3b
is turned off, no voltage is output from terminal LL, and
The light emitting diode LED is also off because the transistor Q□ is off.

The water level in tank 6 has risen. If you go beyond this, you will reach Electrode E.

As a result, a current flows between the thyristor 5CR3 and the thyristor 5CR8, and the light emitting diode LED goes out. Shikatsu Photocoupler P
The light-emitting element of C goes out, so the transistor Q turns on, relay RY3 is excited, the a contact ry3b turns on, voltage is output from terminals I and L, and the light-emitting diode LED turns on of transistor Q. Lights up when turned on.

Further, when the power is turned off, the relay RY3 is in a de-energized state, but since the a contact ry3b is used, no erroneous display occurs.

Immediately after the power is turned on, thyristor 5CR3 is cut off, but because of the delay circuit TM, there is a slight delay in applying the base voltage to the transistor, so relay RY3 is not energized.
There are no false indications. After that, when the thyristor 5CR3 becomes conductive, the base input of the transistor Q□ becomes photocube=yP
Since the light receiving element C is directly connected to the emitter of the transistor Ql, the transistor Q1 is not turned on even after the delay time of the delay circuit 1 has elapsed. Therefore, the relay RY3 remains de-energized, and the automatic alternating operation circuit 5 and the like will not malfunction.

If a power outage occurs while thyristor 5CR3 is conducting, thyristor 5CR3 will shut off and the light-emitting element of the PC will turn off, but relay R will turn off due to a drop in power supply voltage.
Y3 is not excited.

In addition, if a power outage occurs while the thyristor 5CR3 is cut off, the 8 contacts ry3b of the relay RY3 will remain closed until the voltage applied to the relay RY3 falls below the open voltage, and if the voltage falls below p1, the 3 contacts ry3b will remain closed. opens.

In this way, in this embodiment, the output relay contacts for generating the alarm are 8 contacts ry3b, and the operation of the output relay is delayed by the delay circuit TM, so that erroneous display will not occur in any state, including when the power is turned on. It is possible to prevent malfunctions of other circuits. In the embodiment, the thyristor SCR and 5CR3 are cut off and made conductive depending on the height of the water level, but the reverse may be used.

〔Effect of the invention〕

According to the floatless liquid level relay of the present invention, it is possible to prevent false alarms and malfunctions of other circuits in any state including when the power is turned on.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a water level control device to which this invention is applied;
Figure 2 is a circuit diagram of a conventional floatless liquid level relay, Figure 3 is a circuit diagram of a conventional floatless liquid level relay.
The figure is a block diagram of one embodiment of the present invention, and FIG. 4 is a specific circuit diagram thereof. BIy2...Water level detection bridge circuit for full water alarm (liquid level detection circuit), SW...Switching circuit for full water alarm (
Liquid level detection circuit), CR3-... Output relay circuit for full water signal, TM... Delay circuit, LED4... Light emitting diode (load circuit), 5CR3... Thyristor, Q□
...Transistor, RY3...Relay, ry3b
``''' Contact procedure amendment (self-control, case display 11 Fuiwa 58' year 1?! #f Application No. xo4564
Bow 2, Title of Invention 70 - Dress Level Relay 3, Relationship to the Amendment Case Applicant Address 1048 Kadoma, Kadoma City, Osaka Name (
583) Matsushita Electric Works Co., Ltd. Representative Iku Kobayashi 4, Agent 5, Date of amendment order Month, Showa
Day (1) Amend the claims in the specification as shown in the attached sheet. (2) On page 9, line 6 of the specification, replace “Relay 9” with “
"Relay 12" is corrected. (3) On page 9, lines 2 and 3 of the specification, "Light-emitting diode LED manufacturing" is corrected to "Light-emitting diode LED2J." (4) On page 9, lines 3 and 4 of the specification, the phrase "output relay circuit CR construction for full water alarm" is corrected to "output relay circuit CR2 for full water alarm." (5) Specification page 9, line 6, “Light-emitting diode D2”
0 (6) In the 3rd line of page 11 of the specification, the phrase ``turns off'' is corrected to ``turns on''. (7) On page 12, lines 13 and 14 of the specification, the phrase "turns off" is corrected to "turns on." (8) On page 12, line 15 of the specification, the phrase "turned on" is corrected to "turned off." (9) In the 12th page, line 14 of the specification, the phrase ``No longer will be used.'' will be corrected to ``It will be output.'' (10) Page 14, lines 16 to 18 of the specification,
"III. First Switching...Delay Circuit"
The statement should be corrected to read "a delay circuit that holds the second switching element off for a predetermined period of time until the operation of the first switching element stabilizes when the power is turned on." (11) On page 14, line 16 of the specification, "b contact" is corrected to "a contact." (12) Page 17, line 8 of the specification, “Light-emitting diode L
ED4 goes out, and delete the text. (13) First of all, please amend the figures as separate sheets. 2. Claims A liquid level detection circuit that turns on and off a first switch element in response to the height (or low and high) of the liquid level, and a second switch element in response to turning on of the first switch element. by turning off the A contact of the output relay, and turning on the second switch element in response to the turning off of the first switch element to turn on the A contact of the output relay. an output relay circuit and a of the output relay;
A floatless liquid level relay equipped with a load circuit that responds to one turn off of the contact and a circuit that responds when the power is turned on.

Claims (1)

[Claims] a liquid level detection circuit that turns on and off a first switch element in response to the height (t or low height) of the liquid level; and a liquid level detection circuit that turns off a second switch element in response to turning on the first switch element. turning on the a-contact of the output relay, particularly by turning off the a-contact of the output relay and turning on the second switch element in response to the off of the first switch element; an output relay circuit and a of the output relay;
A floatless liquid level relay comprising: a load circuit that responds to turning off a contact; and a delay circuit that delays and transmits turning on/off of the first switch element to the output relay circuit.