A monitoring system and monitoring method for cast iron heat exchanger

Abstract

The present invention provides a monitoring system for a cast iron heat exchanger, comprising a temperature sensor and a smoke sensor arranged at a smoke exhaust port of the cast iron heat exchanger, the smoke exhaust port being connected to a smoke exhaust pipe, a first valve being arranged on the smoke exhaust pipe, a pipe between the first valve and the smoke exhaust port being also connected to an auxiliary smoke exhaust pipe, a fan being arranged on the auxiliary smoke exhaust pipe, a dust removal pipe being arranged at the outlet of the auxiliary smoke exhaust pipe, a dust collection filter box being arranged below the dust removal pipe, the dust collection filter box being connected to a water circulation pipeline of the cast iron heat exchanger; the temperature sensor and the smoke sensor being connected to a PLC controller respectively, and the PLC controller being connected to the fan. The scheme can timely monitor the smoke temperature and smoke density discharged from the heat exchanger, and timely handle any abnormality once it occurs, thereby ensuring the normal operation of the heat exchanger.

Description

Technical Field

[0001] The invention relates to the field of heating, and in particular to a monitoring system and a monitoring method for a cast iron heat exchanger. Background Art

[0002] In the prior art, the known technology is that winter heating is particularly important for the northern region of my country. At present, in the field of heat supply and heat exchange, cast iron heat exchangers are widely used due to the following advantages: 1. With its mature casting process, it creates a large furnace heating surface, adopts an efficient thermal radiation heat transfer method, and enhances the heat transfer effect; 2. High-quality low-sulfur, low-nitrogen, and low-phosphorus pearlite material has extremely strong heat shock resistance and heat fatigue strength, and its thermal conductivity is much better than that of steel boilers, and it has strong corrosion resistance and oxidation resistance. 3. Heat collecting cones are used in the heat exchanger. Regardless of the horizontal or vertical flushing of the flue gas, all the heat collecting cones are flushed by the turbulent flow of the flue gas and form symmetrical steady-state vortices and recirculation zones on their backs. The thermal boundary layer is constantly destroyed and re-formed, which enhances the heat exchange effect. However, most of the cast iron heat exchangers currently used are not monitored. In this way, once the temperature changes or there is flue gas blockage during use, normal heat exchange will not be possible. This is the deficiency of the prior art. Summary of the invention

[0003] The purpose of the present invention is to address the deficiencies in the prior art and to provide a monitoring system and a monitoring method for a cast iron heat exchanger. The scheme can timely monitor the flue gas temperature and smoke density discharged from the heat exchanger. Once an abnormality occurs, it can be handled in time to ensure the normal operation of the heat exchanger.

[0004] This scheme is realized through the following technical measures: a monitoring system for cast iron heat exchanger, including a temperature sensor and a smoke sensor arranged at the exhaust port of the cast iron heat exchanger, the exhaust port is connected to the exhaust pipe, a first valve is arranged on the exhaust pipe, the pipe between the first valve and the exhaust port is also connected to the auxiliary exhaust pipe, a fan is arranged on the auxiliary exhaust pipe, a dust removal pipe is arranged at the outlet of the auxiliary exhaust pipe, a dust collection filter box is arranged below the dust removal pipe, and the dust collection filter box is connected to the water circulation pipeline of the cast iron heat exchanger; the temperature sensor and the smoke sensor are respectively connected to the PLC controller, and the PLC controller is connected to the fan. The temperature sensor can timely monitor the temperature of the exhaust port of the heat exchanger, and the smoke sensor can timely monitor the smoke situation of the exhaust port of the heat exchanger, so that the PLC controller can control the fan switch conveniently. There is an auxiliary smoke exhaust pipe, which can be used for auxiliary smoke exhaust. The dust removal pipe can filter the smoke and dust in the auxiliary smoke exhaust pipe. The dust collection box is used to collect smoke and dust, and can also collect spray water. After filtering the collected spray water, it is sent to the water circulation pipeline of the heat exchanger, which further utilizes the heat energy in the flue gas.

[0005] The dust removal pipe includes a collection area, a mixing area and a dust removal and cooling area. The collection area is arranged below the mixing area, and the dust removal and cooling area is arranged above the mixing area. The collection area is conical, and a dust collection filter box is arranged below the conical collection area. The mixing area is connected to the auxiliary smoke exhaust pipe. The dust removal and cooling area includes a plurality of cross-arranged inclined plates, which are inclined downward, and the front end of each inclined plate exceeds the center line of the dust removal and cooling area. A sprinkler is arranged at the top center of the dust removal and cooling area, and the sprinkler is connected to the water supply pipe. A solenoid valve is arranged on the water supply pipe, and the solenoid valve is connected to the PLC controller. In this way, after the smoke enters the mixing area, it rises to the dust removal and cooling area. In the smoke cooling area, the cross baffles can block the sedimentation of the smoke particles. The sprinkler can cool down some particles with too high temperature, and the water sprayed by the sprinkler can absorb the particles in the smoke. The water flows downward through the baffle, and in the process of flowing, it further purifies the smoke. The dust collecting and filtering box is provided with a filter screen for filtering impurities, so that the impurities can be filtered out and prevented from flowing into the water circulation pipeline of the heat exchanger.

[0006] The sprayer comprises a plurality of circular spray pipes with water outlets, each of which has a different diameter, and the circular spray pipes are concentric circles, so that water spraying ranges with different diameters can be formed, thereby increasing the spraying effect.

[0007] A thermistor is arranged on the top of the dust removal pipe, and the thermistor is connected to an alarm circuit, which includes a transistor VT1, The collector of transistor VT1 is connected to the negative electrode of the power supply through the thermistor RT, the collector of transistor VT1 is connected to the positive electrode of the power supply through the sliding rheostat RB and the resistor R1, the emitter of transistor VT1 is connected to the negative electrode of the power supply, the collector of transistor VT1 is connected to the positive electrode of the power supply through the resistor R2, the collector of transistor VT1 is connected to the input end of NOT gate IC1, the output end of NOT gate IC1 is connected to the input end of NOT gate IC2, the output end of NOT gate IC2 is connected to the input end of NOT gate IC3, the output end of NOT gate IC2 is connected to the negative electrode of the power supply through the indicator light L1 and the resistor R3, the output end of NOT gate IC3 is connected to the negative electrode of the power supply through the indicator light L2 and the resistor R4, the output end of NOT gate IC3 is connected to the base of transistor VT2, the emitter of transistor VT2 is connected to the negative electrode of the power supply, the collector of transistor VT2 is connected to the positive electrode of the power supply through relay J, a diode D is connected in parallel with relay J, and the normally open contact J-1 of relay J is connected in series with alarm B. This allows for a final temperature monitoring of the exhaust flue gas. Once the exhaust flue gas temperature is too high, an alarm will be sounded to alert staff and avoid accidents.

[0008] A monitoring method for a cast iron heat exchanger comprises the following steps: 1) performing temperature and smoke detection on a smoke exhaust port of the cast iron heat exchanger; 2) if the temperature is between a set upper limit temperature and a lower limit temperature, no action is taken; if the temperature exceeds the upper limit temperature, an alarm is sounded, and at the same time, the first valve of the smoke exhaust duct is closed to allow smoke to be discharged from an auxiliary smoke exhaust duct, and a sprinkler is turned on to cool down and remove dust from the smoke; if the temperature is lower than the lower limit temperature, a fan and a sprinkler are turned on to assist in air outlet; 3) if the smoke exceeds a set threshold, an alarm is sounded, the first valve of the smoke exhaust duct is closed, the fan is started to allow smoke to be discharged from the auxiliary smoke exhaust duct, and the sprinkler is turned on to remove dust and cool the smoke.

[0009] In step 2), when the temperature exceeds the set upper limit temperature, the temperature of the flue gas discharged from the auxiliary exhaust pipe is also monitored. If the temperature still exceeds the set upper limit temperature, the cast iron heat exchanger is stopped.

[0010] It can be seen that compared with the prior art, the present invention has outstanding substantive features and significant progress, and the beneficial effects of its implementation are also obvious. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a structural schematic diagram of a specific implementation mode of the present invention.

[0012] Figure 2 It is a schematic diagram of the structure of the dust removal pipe.

[0013] Figure 3 A schematic diagram of the structure of the sprinkler.

[0014] Figure 4 This is the circuit diagram of the alarm circuit.

[0015] In the figure, 1 is a cast iron heat exchanger, 2 is a smoke exhaust pipe, 3 is a first valve, 4 is an auxiliary smoke exhaust pipe, 5 is a dust removal pipe, 6 is a dust collection filter box, 7 is a fan, 8 is a thermistor, 9 is a mixing area, 10 is a dust removal and cooling area, 11 is a collecting area, 12 is an inclined plate, 13 is a sprinkler, 14 is a circular sprinkler pipe, 15 is a water outlet, 16 is a temperature sensor, 17 is a smoke sensor, and 18 is a solenoid valve. DETAILED DESCRIPTION

[0016] In order to clearly illustrate the technical features of the present solution, the present solution is described below through a specific implementation method and in conjunction with its accompanying drawings.

[0017] As can be seen from the attached drawings, the monitoring system for cast iron heat exchangers of the present scheme includes a temperature sensor 16 and a smoke sensor 17 arranged at the exhaust port of the cast iron heat exchanger 1, the exhaust port is connected to the exhaust pipe, a first valve 3 is arranged on the exhaust pipe 2, the pipe between the first valve 3 and the exhaust port is also connected to the auxiliary exhaust pipe 4, a fan 7 is arranged on the auxiliary exhaust pipe 4, a dust removal pipe 10 is arranged at the outlet of the auxiliary exhaust pipe 4, a dust collection filter box 6 is arranged below the dust collection pipe 10, and a filter net for filtering impurities is arranged in the dust collection filter box 6. The dust collection filter box 6 is connected to the water circulation pipeline of the cast iron heat exchanger 1; the temperature sensor 16 and the smoke sensor 17 are respectively connected to the PLC controller, the PLC controller adopts the PLC controller commonly used in the art, the temperature sensor and the smoke sensor are both sensors known in the art, and the PLC controller is connected to the fan 7.

[0018] The dust removal pipe 5 includes a collection area 11, a mixing area 9 and a dust removal and cooling area 10. The collection area 11 is arranged below the mixing area 9, and the dust removal and cooling area 10 is arranged above the mixing area 9. The collection area 11 is conical, and a dust collection filter box 6 is arranged below the conical collection area 11. The mixing area 9 is connected to the auxiliary smoke exhaust pipe 4. The dust removal and cooling area 10 includes a plurality of cross-arranged inclined plates 12, which are inclined downward, and the front end of each inclined plate 12 exceeds the center line of the dust removal and cooling area 10. A sprinkler 13 is arranged at the top center of the dust removal and cooling area 10. The sprinkler 13 is connected to the water supply pipe, and a solenoid valve 18 is arranged on the water supply pipe. The solenoid valve 18 is connected to the PLC controller. The sprinkler 13 includes a plurality of circular spray pipes 14 with water outlets 15. The diameter of each circular spray pipe 14 is different, and the circular spray pipes 14 are concentric circles.

[0019] A thermistor 8 is provided at the top of the dust removal pipe 5. The thermistor is connected to the alarm circuit. The thermistor is marked with RT in the circuit diagram. The alarm circuit includes a transistor VT1, The collector of transistor VT1 is connected to the negative electrode of the power supply through the thermistor RT, the collector of transistor VT1 is connected to the positive electrode of the power supply through the sliding rheostat RB and the resistor R1, the emitter of transistor VT1 is connected to the negative electrode of the power supply, the collector of transistor VT1 is connected to the positive electrode of the power supply through the resistor R2, the collector of transistor VT1 is connected to the input end of NOT gate IC1, the output end of NOT gate IC1 is connected to the input end of NOT gate IC2, the output end of NOT gate IC2 is connected to the input end of NOT gate IC3, the output end of NOT gate IC2 is connected to the negative electrode of the power supply through the indicator light L1 and the resistor R3, the output end of NOT gate IC3 is connected to the negative electrode of the power supply through the indicator light L2 and the resistor R4, the output end of NOT gate IC3 is connected to the base of transistor VT2, the emitter of transistor VT2 is connected to the negative electrode of the power supply, the collector of transistor VT2 is connected to the positive electrode of the power supply through relay J, a diode D is connected in parallel with relay J, and the normally open contact J-1 of relay J is connected in series with alarm B.

[0020] A method for monitoring a cast iron heat exchanger using the above system is characterized by comprising the following steps: 1) temperature and smoke detection at the exhaust port of the cast iron heat exchanger; 2) if the temperature is between the set upper and lower limits, no action will be taken; if the temperature exceeds the upper limit, an alarm will be sounded, and the first valve of the exhaust pipe will be closed at the same time, so that the smoke will be discharged from the auxiliary exhaust pipe, and the sprinkler will be turned on to cool down and remove dust from the smoke; if the temperature is lower than the lower limit, the fan and sprinkler will be turned on to assist in air outlet; when the temperature exceeds the set upper limit, the temperature of the smoke discharged from the auxiliary exhaust pipe will also be monitored, and if the temperature still exceeds the set upper limit, the cast iron heat exchanger will be stopped. 3) If the smoke exceeds the set threshold, an alarm will be sounded, the first valve of the exhaust pipe will be closed, the fan will be started, so that the smoke will be discharged from the auxiliary exhaust pipe, and the sprinkler will be turned on to remove dust and cool the smoke.

[0021] The present invention is not limited to the above-mentioned specific embodiments. Changes, modifications, additions or substitutions made by ordinary technicians in this field within the essential scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A monitoring system for a cast iron heat exchanger, characterized in that: It includes a temperature sensor and a smoke sensor arranged at the exhaust port of the cast iron heat exchanger, the exhaust port is connected to the exhaust pipe, a first valve is arranged on the exhaust pipe, the pipe between the first valve and the exhaust port is also connected to the auxiliary exhaust pipe, a fan is arranged on the auxiliary exhaust pipe, a dust removal pipe is arranged at the outlet of the auxiliary exhaust pipe, a dust collection filter box is arranged below the dust removal pipe, and the dust collection filter box is connected to the water circulation pipeline of the cast iron heat exchanger; the temperature sensor and the smoke sensor are respectively connected to the PLC controller, and the PLC controller is connected to the fan; The dust removal pipe includes a collection area, a mixing area and a dust removal and cooling area. The collection area is arranged below the mixing area, and the dust removal and cooling area is arranged above the mixing area. The collection area is conical, and a dust collection filter box is arranged below the conical collection area. The mixing area is connected to the auxiliary smoke exhaust pipe. The dust removal and cooling zone includes a plurality of cross-arranged inclined plates, the inclined plates are inclined downward, and the front end of each inclined plate exceeds the center line of the dust removal and cooling zone. A sprinkler is arranged at the top center of the dust removal and cooling zone, and the sprinkler is connected to a water supply pipe. A solenoid valve is arranged on the water supply pipe, and the solenoid valve is connected to a PLC controller. The sprayer comprises a plurality of circular spray pipes with water outlets, each circular spray pipe has a different diameter, and the circular spray pipes are concentric circles; A thermistor is arranged on the top of the dust removal pipe, and the thermistor is connected to an alarm circuit, which includes a transistor VT1, The collector of transistor VT1 is connected to the negative electrode of the power supply through the thermistor RT, the collector of transistor VT1 is connected to the positive electrode of the power supply through the sliding rheostat RB and the resistor R1, the emitter of transistor VT1 is connected to the negative electrode of the power supply, the collector of transistor VT1 is connected to the positive electrode of the power supply through the resistor R2, the collector of transistor VT1 is connected to the input end of NOT gate IC1, the output end of NOT gate IC1 is connected to the input end of NOT gate IC2, the output end of NOT gate IC2 is connected to the input end of NOT gate IC3, the output end of NOT gate IC2 is connected to the negative electrode of the power supply through the indicator light L1 and the resistor R3, the output end of NOT gate IC3 is connected to the negative electrode of the power supply through the indicator light L2 and the resistor R4, the output end of NOT gate IC3 is connected to the base of transistor VT2, the emitter of transistor VT2 is connected to the negative electrode of the power supply, the collector of transistor VT2 is connected to the positive electrode of the power supply through relay J, a diode D is connected in parallel with relay J, and the normally open contact J-1 of relay J is connected in series with alarm B.

2. The monitoring system for cast iron heat exchanger according to claim 1, characterized in that: A filter screen for filtering impurities is arranged in the dust collecting filter box.

3. A method for a monitoring system for a cast iron heat exchanger based on any one of claims 1 or 2, characterized in that The steps include: 1) Conduct temperature and smoke detection on the exhaust port of the cast iron heat exchanger; 2) If the temperature is between the set upper and lower limits, no action will be taken. If the temperature exceeds the upper limit, an alarm will be sounded and the first valve of the smoke exhaust pipe will be closed to allow smoke to be discharged from the auxiliary smoke exhaust pipe. The sprinkler will be turned on to cool and remove dust from the smoke. If the temperature is lower than the lower limit, the fan and sprinkler will be turned on to assist in air discharge. 3) If the smoke exceeds the set threshold, an alarm will be sounded, the first valve of the smoke exhaust duct will be closed, the fan will be started to discharge the smoke from the auxiliary smoke exhaust duct, and the sprinkler will be turned on to remove dust and cool the smoke.

4. The method according to claim 3, characterized in that: In step 2), when the temperature exceeds the set upper limit temperature, the temperature of the flue gas discharged from the auxiliary exhaust pipe is also monitored. If the temperature still exceeds the set upper limit temperature, the cast iron heat exchanger is stopped.

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