A sewage treatment system micro filter chain break judgment and control circuit

Abstract

The utility model discloses a kind of sewage treatment system microfilter chain break judgment and control circuit, belong to electrical control technical field.Circuit is by time relay KT1, KT2, counter CT1, intermediate relay KA1~KA4, with lamp reset button SBL1 and proximity switch KQ2 constitute pure hardware structure, without PLC.Motor operation, KQ2 detects driven gear pulse, KT1 provides adjustable counting window, CT1 carries out adjustable set value counting to pulse;Through the 0.1s period forced zero of KT2 and the instant reset of KA2 reach standard, form double redundancy mechanism, and strong anti-interference capability.When chain is broken, KQ2 has no pulse output, KT1 delay drives KA3, KA4 action, triggers sound light alarm and cut off motor power supply to realize interlock stop;After troubleshooting, press SBL1 can reset.Circuit parameter of this utility model is adjustable, low in cost, maintenance-free, applicable to sewage plant high humidity corrosion environment, can effectively avoid filter screen blockage and secondary damage.

Description

Technical Field

[0001] This utility model relates to the field of electrical control technology, specifically to a circuit for judging and controlling the chain breakage of a microfilter in a sewage treatment system. Background Technology

[0002] Microfiltration machines are key filtration equipment in wastewater treatment plants. Their drive chains are constantly immersed in humid and corrosive environments, making them highly susceptible to fatigue, wear, and even sudden breakage. Once the chain breaks, the driven wheel stops rotating, and impurities trapped on the filter screen cannot be discharged in time. This can quickly lead to filter clogging, rising water levels, motor overload, and in severe cases, secondary accidents such as damage to the reducer and wastewater overflow.

[0003] Currently, the industry commonly uses two monitoring methods: First, a speed sensor is installed on the driven shaft, and a PLC or microcontroller collects pulses and calculates the speed; if the speed falls below a threshold, an alarm is triggered and the machine stops. Second, a mechanical stall switch is used, triggered by centrifugal force or a lever to activate a microswitch. Both solutions have the following drawbacks:

[0004] 1. PLC / microcontroller systems are expensive and require a lot of programming work. They also have a high failure rate in humid environments or environments with high hydrogen sulfide concentrations. Maintenance personnel need to have professional programming skills.

[0005] 2. Mechanical stall switches have low sensitivity and often fail due to scaling and jamming. They also cannot distinguish between "temporary jamming" and "true chain breakage", resulting in frequent false activation and failure to activate.

[0006] 3. Existing electronic solutions are sensitive to external electromagnetic interference, and excessively long signal cables can easily introduce glitch, causing counting errors.

[0007] 4. Most systems require additional configuration of isolated power supplies, analog quantity modules or communication modules, and there are many types of spare parts, making it difficult for sewage treatment plant technicians to carry out on-site emergency repairs.

[0008] Therefore, the market urgently needs a chain break detection circuit that can achieve integrated "counting-delay-judgment-protection" functions without PLC or software, using only hardware. It should be low in cost, adjustable in parameters, resistant to moisture and interference, and able to complete the chain break judgment and output reliable shutdown and alarm contacts in a short time to reduce the risk of secondary damage to the microfilter and reduce downtime for maintenance. Utility Model Content

[0009] The purpose of this invention is to overcome the above-mentioned shortcomings of the prior art and provide a "pure hardware, low cost, and high reliability" microfilter chain breakage judgment and control circuit. It can complete chain breakage identification, audible and visual alarm and motor interlock shutdown in a short time without the need for PLC or microcontroller. Moreover, all components can operate stably for a long time in the high humidity and corrosive environment of sewage treatment plants.

[0010] To achieve the above objectives, this utility model provides the following technical solution:

[0011] The present invention relates to a microfilter chain breakage detection and control circuit for a sewage treatment system, comprising time relays KT1 and KT2, counter CT1, intermediate relays KA1, KA2, KA3, and KA4, a reset button with an indicator light SBL1, and a proximity switch KQ2 installed on the side of the driven gear.

[0012] The coil of time relay KT1 is connected in series with the motor running contact and then connected to the power supply. The time delay disconnect contact of time relay KT1 is connected in series with the coil of intermediate relay KA3 to form the first time delay branch.

[0013] The counting input terminal of counter CT1 is connected to the signal contact of proximity switch KQ2, the reset terminal of counter CT1 is connected to the normally open contact of KA2, and the output contact of counter CT1 is connected in series with the coil of intermediate relay KA2 to form a counting-reset circuit.

[0014] In the power supply circuit of the intermediate relay KA2 coil, the normally closed contact before the output contact of the counter CT1 and the time-delayed disconnect contact of the time relay KT1 are connected in series to ensure that when the count value of the counter CT1 reaches the set value N, the intermediate relay KA2 is energized instantaneously and self-held, and then the time relay KT1 and the counter CT1 are reset simultaneously through its normally open contact.

[0015] The time relay KT2 is set to a 0.1s cycle timer. Its coil is powered by its own delayed disconnect contact and the normally closed contact of the intermediate relay KA2 in series to form a 0.1s pulse source. The pulse source contact is connected in parallel to the reset contact of the intermediate relay KA2 to provide a periodic forced zeroing signal for the counter CT1 and the time relay KT1.

[0016] The coil of intermediate relay KA3 is controlled by the time delay disconnect contact of time relay KT1. After the time delay T of time relay KT1 is reached, intermediate relay KA3 is energized, and its normally open contact closes to cause the coil of intermediate relay KA4 to be energized and self-holding. The normally open contact of intermediate relay KA4 drives the audible and visual alarm and outputs a passive alarm point. At the same time, the normally closed contact of intermediate relay KA4 is connected in series with the motor control circuit to realize interlocked shutdown.

[0017] The normally closed contact of the illuminated reset button SBL1 is connected in series with the self-holding circuit of the intermediate relay KA4. When the illuminated reset button SBL1 is pressed, the intermediate relay KA4 is de-energized, the alarm is cleared and the circuit returns to standby state.

[0018] The delay value T of the time relay KT1 and the set value N of the counter CT1 can both be adjusted on-site to adapt to different chain speeds and operating conditions.

[0019] As a further technical solution of this utility model: the proximity switch KQ2 is a two-wire or three-wire DC type, and its output contact directly drives the counting input terminal of the counter CT1 without additional isolation.

[0020] As a further technical solution of this utility model: the 0.1s cycle contact of the time relay KT2 is connected in parallel with the instantaneous reset contact of the intermediate relay KA2 to form a dual redundancy mechanism of "instant reset upon pulse attainment + forced zeroing of the cycle" to prevent malfunctions caused by pulse omission or interference.

[0021] As a further technical solution of this utility model: the output terminals of the intermediate relay KA4 are provided with one set of normally open and one set of normally closed, providing passive contacts to facilitate expansion connection with field DCS or PLC.

[0022] As a further technical solution of this utility model: all components are installed in an IP65 flame-retardant housing, and the buttons, indicator lights, and inlet / outlet cable glands all meet the long-term operation requirements of sewage treatment plants in humid and corrosive environments.

[0023] This utility model has the following advantages and beneficial effects:

[0024] 1. This utility model completely eliminates the need for software, communication, and isolation modules while maintaining high reliability.

[0025] 2. The chain breakage detection and shutdown are completed within 10 seconds, which can avoid filter clogging and secondary mechanical damage. It is suitable for humid and corrosive environments such as sewage treatment plants, papermaking, and printing and dyeing, and has significant economic benefits and promotional value. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of a utility model. Detailed Implementation

[0027] The present invention will be further described below with reference to the embodiments. It should be noted that these are merely examples and descriptions of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the concept of the present invention or exceed the scope defined by the claims, they should all be considered to fall within the protection scope of the present invention.

[0028] See Figure 1 This utility model discloses a circuit for detecting and controlling chain breakage of a microfilter in a wastewater treatment system. The circuit includes:

[0029] The system includes time relays KT1 (adjustable delay value T), KT2 (0.1 s cycle timer), counter CT1 (adjustable set value N), intermediate relays KA1 to KA4, an illuminated reset button SBL1, a buzzer, and a proximity switch KQ2 for detecting the driven gear. All components are housed in a flame-retardant enclosure, with only three pairs of terminals exposed to the outside: power supply, motor control, and alarm contacts. On-site wiring is plug-and-play.

[0030] 2. Working principle

[0031] a) The moment the motor running contacts close, KT1 and CT1 are simultaneously energized and begin to work;

[0032] b) KQ2 inputs a counting signal to CT1 every time it detects a gear pulse;

[0033] c) When the number of pulses within 10 seconds is greater than or equal to N, the output contact of CT1 closes, KA2 is energized instantaneously and self-holds, and its normally open contact immediately resets KT1 and CT1 simultaneously. The system determines that "the chain is normal" and the circuit enters the next 10-second window.

[0034] d) KT2 independently constitutes a 0.1s oscillator. Its delayed disconnect contact opens once every 0.1s, forming a "periodic forced zeroing" pulse through the normally closed contact of KA2. This pulse is connected in parallel with the "standard zeroing" pulse of KA2 to form a dual redundant reset mechanism to prevent interference or brief jamming from causing false counting.

[0035] e) If the chain breaks, the driven gear stops rotating, KQ2 has no pulse, KA2 cannot move, and after the delay T of KT1 (default 10s, adjustable) is reached, its delay disconnect contact opens, KA3 is energized, the normally open contact of KA3 causes KA4 to be energized and self-holding, the normally open contact of KA4 drives the audible and visual alarm, and the normally closed contact of KA4 is connected in series with the motor control circuit to cut off the power supply, realizing the interlocked stop.

[0036] f) After troubleshooting, press SBL1. The KA4 self-holding circuit will disconnect, the alarm will disappear, and the circuit will return to standby mode.

[0037] 3. Adjustable parameters:

[0038] a) KT1 delay value T: continuously adjustable from 2 to 30 seconds;

[0039] b) CT1 setting value N: 1–99 can be set arbitrarily;

[0040] c) The panel knobs can be used to adapt to different chain speeds and gears with different numbers of teeth on site.

[0041] Example

[0042] 1. Mechanical Layout

[0043] Four metal protrusions, each 3mm high and 6mm wide, are evenly distributed on the end face of the driven gear and are integrally machined with the gear body. A two-wire inductive proximity switch KQ2 is mounted on the outside of the gear housing via an M12 bracket, with a 5–10mm gap between the probe end face and the top of the protrusions. Each time the gear rotates, the four protrusions sequentially pass over the probe, and KQ2 outputs a periodic pulse signal.

[0044] 2. Electrical connection

[0045] KQ2 is a two-wire system: the brown wire is connected to 24VDC+, and the blue wire is connected to the pulse input terminal CP1 of counter CT1. CT1, KT1, KT2 and all relay coils are powered through the normally open auxiliary contact of the motor running contactor to ensure that "the detection stops when the motor stops".

[0046] 3. Parameter settings

[0047] a) KT1 delay T: adjustable;

[0048] b) CT1 setting N: Adjustable;

[0049] c) KT2 has a fixed short cycle and provides a forced zeroing pulse.

[0050] 4. Action Flow

[0051] ① Under normal conditions: The protrusion continuously passes the probe. CT1 accumulates the set number of pulses before the delay of KT1 arrives. KA2 is activated and immediately resets KT1 and CT1, and the circuit enters the next detection window.

[0052] ② When the chain breaks: the gear stops rotating and there is no pulse; after the delay of KT1, KA3→KA4 engage sequentially, the audible and visual alarm is activated, the normally closed contact of KA4 cuts off the motor contactor, and the microfilter stops.

[0053] ③ Reset: After troubleshooting, press SBL1, KA4 self-holding is released, the alarm is extinguished, and the circuit returns to standby.

[0054] 5. Routine maintenance

[0055] ① Regularly check the cleanliness of the probe surface and remove accumulated dust; if the protrusion is deformed, it can be repaired with a file. After replacing with the same type of two-wire proximity switch, no recalibration is required; it can be put into operation immediately upon power-on.

[0056] ②This implementation method uses a single two-wire proximity switch with a four-protrusion structure, which is simple to wire, has strong anti-interference ability, and is suitable for long-term stable operation in humid and corrosive environments of sewage treatment plants.

[0057] The above is an exemplary description of the utility model. Obviously, the specific implementation of the utility model is not limited to the above-described manner. Any non-substantial improvement made by adopting the inventive concept and technical solution of the utility model, or the direct application of the inventive concept and technical solution to other situations without modification, shall be within the protection scope of the utility model.

Claims

1. A circuit for detecting and controlling chain breakage of a microfilter in a wastewater treatment system, characterized in that, It includes time relays KT1 and KT2, counter CT1, intermediate relays KA1, KA2, KA3 and KA4, a reset button with an indicator light SBL1, and a proximity switch KQ2 installed on the side of the driven gear. The coil of time relay KT1 is connected in series with the motor running contact and then connected to the power supply. The time delay disconnect contact of time relay KT1 is connected in series with the coil of intermediate relay KA3 to form the first time delay branch. The counting input terminal of counter CT1 is connected to the signal contact of proximity switch KQ2, the reset terminal of counter CT1 is connected to the normally open contact of KA2, and the output contact of counter CT1 is connected in series with the coil of intermediate relay KA2 to form a counting-reset circuit. The normally closed contact before the time-delay disconnect contact of the time relay KT1 is connected in series with the output contact of the counter CT1 in the power supply circuit of the intermediate relay KA2 coil. The time relay KT2 is set to a 0.1s cycle timer. Its coil is powered by its own delayed disconnect contact and the normally closed contact of the intermediate relay KA2 in series to form a 0.1s pulse source. The pulse source contact is connected in parallel to the reset contact of the intermediate relay KA2 to provide a periodic forced zeroing signal for the counter CT1 and the time relay KT1. The coil of intermediate relay KA3 is controlled by the time delay disconnect contact of time relay KT1. After the time delay T of time relay KT1 is reached, intermediate relay KA3 is energized, and its normally open contact closes to cause the coil of intermediate relay KA4 to be energized and self-holding. The normally open contact of intermediate relay KA4 drives the audible and visual alarm and outputs a passive alarm point. At the same time, the normally closed contact of intermediate relay KA4 is connected in series with the motor control circuit to realize interlocked shutdown. The normally closed contact of the illuminated reset button SBL1 is connected in series with the self-holding circuit of the intermediate relay KA4. When the illuminated reset button SBL1 is pressed, the intermediate relay KA4 is de-energized, the alarm is cleared, and the circuit returns to standby mode.

2. The wastewater treatment system microfilter chain breakage judgment and control circuit according to claim 1, characterized in that, The proximity switch KQ2 is a two-wire or three-wire DC type, and its output contact directly drives the counting input terminal of the counter CT1 without the need for additional isolation.

3. The wastewater treatment system microfilter chain breakage judgment and control circuit according to claim 1, characterized in that, The 0.1s cycle contact of the time relay KT2 is connected in parallel with the instantaneous reset contact of the intermediate relay KA2 to form a dual redundancy mechanism.

4. The wastewater treatment system microfilter chain breakage judgment and control circuit according to claim 1, characterized in that, The intermediate relay KA4 has one set of normally open and one set of normally closed output terminals, providing passive contacts to the outside.

5. The wastewater treatment system microfilter chain breakage judgment and control circuit according to claim 1, characterized in that, The delay value T of the time relay KT1 is adjustable.

6. The wastewater treatment system microfilter chain breakage judgment and control circuit according to claim 1, characterized in that, The set value N of the counter CT1 is adjustable.

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