Development of monitoring device for main drainage

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Development of monitoring device for mine main drainage system

mine main drainage system is an important part of large-scale equipment in coal mines. If the main drainage system cannot operate normally, it will endanger the safety production of the whole mine, and even cause heavy and catastrophic property loss accidents. The existing 23 main drainage systems of Jixi Mining (Group) Co., Ltd. have no high and low water level monitoring and alarm, and the pump suction empty alarm device, which only relies on the inspection of operators. If the water level is abnormal, the bottom valve of the suction pipe is blocked and cannot be found in time, it will cause pump flooding or even well flooding accidents. Similar accidents have occurred in some mines of the group company before. In view of this situation, we have developed a monitoring device for the main drainage pump

1 working principle

the monitoring device is mainly realized by two plug-in boards of water level and suction

1.1 working principle of water level display and alarm of water sump

as shown in Figure 1. In Figure 1, the part circled by the dotted line is a six segment water level board plug-in circuit, in which j1-j6 is a six segment water level action execution relay, which is driven by six sets of t1~t12 (only three sets are shown in the figure) two-stage transistor amplification circuits. In these six sets of amplification circuits, J1 is a water release type. J2~j6 are closed with water

Figure 1 water level display and alarm circuit

j1 is the first stage of water level display relay. When there is water at water level 1, the resistance value of water is generally between 100k~1m Ω, and the base current flowing through R2 is about 0.02mA. The triode T1 is amplified, and the current flowing through R1 is 1.5mA. At this time, T1 is on, T2 is off, J1 is in the released state, the normally closed point of J1 is closed, and LED1 is illuminated. When there is no water at water level 1, T1 is cut off, T2 is turned on and J1 is closed, J1 normally open point is closed, language alarm Y1 sounds, and X8 emits red light to indicate the low warning line water level, because there is often water at water level 1. Therefore, J1 is in the state of water release

j2 is the second stage water level indication relay. When there is water in water level 2, T3 base current is about 0.02mA, T4 base current is 0.5mA, T4 is on, J2 is electrically engaged, LED2 is illuminated, indicating water level 2

the working principle of J3, J4, J5 and J6 is the same as that of J2, and the parameters of amplification circuit elements are basically the same. The amplification factor of triode t1~t12 β The value should be greater than 100

r31, R32 ~ R36 are the relay step-down resistance, with a value of 120 Ω ~ 390 Ω. D1 is the power rectifier bridge, and D2 ~ D7 are the freewheeling triodes. For the case of multiple relays in parallel and small relay high-power triodes, C3 ~ C8 anti-interference capacitors can not be used, but can also be directly connected in parallel to the be junction of the first stage amplification triode. J6 is a high warning water level relay. When J6 is pulled in, the normally open point of J6 is closed, led6 lights up, indicating the water level of the 6th section, Y2 sounds, and the high warning water level voice alarm

since some main drainage systems have two disconnected water tanks a and B, each set of water level protection has two water level plug-ins to indicate the water levels of the two water tanks a and B respectively. J6 in Figure 1 ˊ And J1 ˊ It is the high and low water level relay contact of the water level plug-in of water tank B, so that the two water level plug-ins share the high and low water level audible and visual signals Y2, Y1, X7, X8 alarm system

K1 in Figure 1 is the power switch, B is the 220v/36v, 15W transformer, and K2 is a double pole double throw voice pause switch. When a high warning water level alarm occurs in the water tank a, sometimes in order to adjust the negative peak, the pump is not immediately started to discharge water, but first toggle the toggle switch K2, turn off the high warning water level voice alarm in the water tank a, and start to discharge water into the water tank B. When the water tank B reaches the high warning level, J6 ˊ When it is closed, Y2 can send out the voice alarm of high warning water level again. At this time, it is necessary to turn on the pump for drainage. When the water level of the two water tanks drops, J6 ˊ After release, the voice pause switch can be restored. When the voice pause switch K2 or K3 is turned off, the voice pause alarm lamp x9 will light up, prompting the pump driver to close K2 to resume the voice alarm function after the voice alarm is eliminated. Wy1, wy2 and wy3 are the 78 series three terminal stabilized voltage power supply blocks of voice alarm. Since the input voltage of the 78 series three terminal stabilized voltage block is only allowed to be twice as high as the output voltage of the new TPE products that will be launched at present, to stabilize the voltage from DC 30V to DC 6V, three three three terminal stabilized voltage blocks need to be connected in series, that is, 7824, 7812 and 7806 in series. The middle pin of the 78 series three terminal stabilized voltage block is the input and output common end, Here, only 7806 is drawn to show the working voltage of the voice alarm system with its high video frequency

the output voltage of rectifier bridge D1 is DC 30V, the positive pole is connected to the ground, and the ground can be connected with the grounding system of the main drainage pump room. This has two advantages. One advantage is that six sections of water level electrode wires can be put into the chamber to be monitored, eliminating the water inflow of a total electrode that is most vulnerable to corrosion by underground water, and reducing the maintenance of water level electrode; Another advantage is to provide a grounding electrode for the entire monitoring device housing. Six water level electrodes can be made into unequal length electrodes with six 1.0mm2 plastic control wires. In order to prevent corrosion to the electrodes, a carbon brush can be welded on the front end of each electrode, and then 1:1 glue is used to seal the exposed copper wire and welding points of the electrode. You can also use cold patching agent or epoxy resin glue to seal all 7-core cables and 7 carbon brushes in one piece Φ The 15mm plastic pipe is made into a water electrode, which is more convenient for the installation and cleaning of the electrode

1.2 the working principle of water pump operation display and suction alarm

is shown in Figure 2. In Figure 2, the part circled by the dotted line is the suction board circuit. The suction board and the water level board share a set of 30V DC power supply, which is composed of three tubes T1 ~ T10, five water pump suction charging detection circuits, and the water pump operation display circuit is composed of triodes T11 ~ T15. Lh1~lh5 are the current transformers for the current detection of the water pump starting cabinet

the current transformer is Zhou Changyi, director of the raw materials department of the Ministry of industry and information technology of Y, who published a signed article in this newspaper on October 11, 2016, pointing out that the wha/10ma current transformer is installed on the ammeter of the starting cabinet of the water pump and is connected in series with the ammeter. When 1# pump is started, LH1 can induce current. If the rated current of the water pump is 100A and the electric transformer of the starting cabinet is 100a/5a, the rated current flowing through the ammeter is 5a, and through LH1 mutual inductance, The secondary induction of LH1 may cause the sealing ring to fail after working for too long, resulting in serious oil leakage of 2.5mA in the oil cylinder. After D1 rectification, C1 filtering, R1, W1, R11 partial voltage, 10V voltage can be generated at both ends of (10) and (16). On the one hand, this voltage makes T11 turn on, J1 has electric pickup, X2 has luminous indication, 1 × pump runs, and on the other hand, T1 can be turned on by adjusting W1, Make the current passing through the normally open point of J1 and R3 flow through T1 instead of R4, so that T6 is turned off, and the suction relay JK is not pulled in. When the suction tap is blocked or the water tank is evacuated and other faults occur, the current of the starting cabinet is reduced by 30% to 70A, the voltage between (10) and (16) is reduced to 7V, the partial voltage obtained at potentiometer W1 is also reduced, LED1 is cut off, T1 is cut off, and the current passes through the normally open contact of J1, through R3 R4 makes T6 turn on with base current, and JK electrically pulls in, sending a red light signal of suction alarm

the five sets of suction circuits in Figure 2 are the same. The input and output of these five sets of suction circuits form the relationship of NAND gate circuit, that is, no matter how many pumps are running, as long as there is suction when the current of one pump drops, JK will act and send an audible and visual alarm

Figure 2 pump suction alarm and operation display circuit

this suction protection circuit can work normally when the current flowing through the ammeter of the starting cabinet is 0.5 ~ 10A. During installation and commissioning, you can first turn off the voice alarm to prevent the DC voltage fluctuation after the voice sound from affecting the commissioning, and then adjust the potentiometers W1 ~ W5 to the lowest end, so that the operation light x2 and suction alarm light X1 are on when 1# pump is on, and then gradually raise the potentiometer, Until the light-emitting diode LED1 emits light slightly, at this time, T1 is turned on, T6 is cut off, JK is released, and the suction alarm lamp X1 is off. In this way, when the water pump is empty and the current drops, T1 will be cut off, and the suction relay JK is electrically closed, playing the role of suction alarm

2 main functions

(1) the monitoring device can simultaneously indicate the water tanks of the main and auxiliary water tanks, and the water level of each water tank is divided into six sections

(2) the monitoring device can display the operation status of up to five water pumps at the same time

(3) it has the voice alarm function of high water level and low water level. When the red light of the six section water level display is fully on, the voice alarm of high water level is given, and when it is completely off, the voice alarm of low water level is given

(4) when the pump empties the voice alarm, no matter which pump idles due to lack of water, there is a emptied voice alarm

(5) the voice pause can be controlled artificially, and the red light is displayed

3 conclusion

this monitoring device has the advantages of low production cost, convenient use, installation, maintenance and low failure rate. Our company has 12 mines, 16 pairs of production wells, 23 main drainage systems and 75 water pumps. After being installed and put into operation in August 2003, after half a year of operation, the water level of each water tank is displayed accurately, there is no false alarm, and the operation is safe and reliable

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