CN201740451U - Automatic deicing control system for fan of cooling tower - Google Patents
Automatic deicing control system for fan of cooling tower Download PDFInfo
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- CN201740451U CN201740451U CN2009203532476U CN200920353247U CN201740451U CN 201740451 U CN201740451 U CN 201740451U CN 2009203532476 U CN2009203532476 U CN 2009203532476U CN 200920353247 U CN200920353247 U CN 200920353247U CN 201740451 U CN201740451 U CN 201740451U
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Abstract
The utility model provides an automatic deicing control system for a fan of a cooling tower. The automatic deicing control system comprises a double speed motor M, an MCC control cabinet and a PLC. A three-phase power supply is connected to the double speed motor M, and a power circuit of the three-phase power supply is connected to the MCC control cabinet by a current transformer. The MCC control cabinet is connected with a field operation box. The whole control system is also connected with the PLC. The system can automatically deice the cooling tower in cold climate and has low operation and maintenance cost.
Description
Technical field
The utility model relates to cold district blower fan of cooling tower automated de-icing system.
Background technology
In iron and steel metallurgical industry, cooling tower is a requisite heat-exchange apparatus in the circular water treating system.Yet at cold district, particularly in the winter time, the icing phenomenon of its blower fan is serious before the cooling tower operation, all brings many difficulties for safety in production and Operation and Maintenance.At China's cold district, can reach 5 wheat harvesting periods local annual ice period, and minimum temperature reaches subzero 40 ℃.Enter winter, it is serious to freeze on cooling tower air inlet shutter, make whole shutter form the ice curtain, almost sealed inlet and outlet, cause passing in and out the wind incoming air area and reduce, the turnover air quantity reduces, and influences the cooling effect of tower, ice curtain in addition and may throw away in that motor is in service, also have serious potential safety hazard.In order to guarantee the normal operation and the cooling effect of cooling tower, common way is to allow the operator make a hole in the ice, but might damage together with shutter in the process of making a hole in the ice, and has caused the significant wastage of human and material resources.In the coldest, even filler is frozen, after filler freezes, influence the efficient of filler, also influence the cooling effect of tower.What is more, and the loading of the ice that is increased after freezing may cause distortion on the cooling tower structure, cave in.The anti-icing method of common in the market cooling tower has methods such as anti-frozen pipe, shower are installed, but this all needs to increase construction, operation and the maintenance cost of cooling tower.
Summary of the invention
Technical problem to be solved in the utility model is: a kind of automatic deicing control system of cooling tower fan is provided, and can be the cooling tower automatic de-icing under cold climate by native system, and operation and maintenance cost are low.
The technical scheme that the utility model adopted is: comprise double-speed motor, MCC switch board and PLC; The three-phase electrical source of power is connected to double-speed motor, also is connected to the MCC switch board by current transformer on its motor circuit, is connected to the execute-in-place case on the MCC switch board, and The whole control system also is connected to PLC.
Advantage of the present utility model: after using this control system, only need selected automatic de-icing mode of operation on HMI (actual effect can be come on-the-spot the adjustment by setting the blower fan reversing time), the freezing various influences that cause just can be eliminated by system.It is the damage of making a hole in the ice and may cause equipment that the people had both been avoided in the application of this cover system, has saved manpower and materials, can also prevent from freezing equipment to be caused a series of influences.Compare with other technologies on the market, this programme is simple, and the deicing effect is comparatively obvious, efficiently solves the situation that winter, exclusive cooling tower seriously froze, and has improved the reliability of cooling tower self-operating.
Description of drawings
Fig. 1 is the power loop circuit diagram.
Fig. 2 is running control circuit figure.
Fig. 3 is state and indicating circuit figure.
Fig. 4 is the I/O of PLC system (input and output) some allocation plan.When at the enterprising line operate of HMI (man-machine interface), finish the supervision of motor status and and start and stop control by the input and output point of PLC.
Native system has been realized high-speed cruising, low cruise, three kinds of methods of operation of low speed and reverse operation of double-speed motor, and carries out start stop operation on control box and the HMI (man-machine interface) at the scene.Among the figure, M: double-speed motor; Q: breaker; K: contactor and auxiliary reclay; F: electrothermal relay; T: current transformer; S: selector switch and button; H: indicator lamp; PA: ammeter.
Fig. 5 is the operation principle flow chart.By timing program, no matter which kind of duty blower fan was in originally, can regularly allow blower fan of cooling tower automatically switch to the low speed and reverse operation, after finishing, deicing is back to former running status voluntarily.
The specific embodiment
The purpose of using cooling tower is to reduce the temperature of water in the tower.Pass through blower fan when using at ordinary times and just changeing the higher air of temperature in the extraction tower, through transmission of heat by contact and evaporative heat loss, airborne heat is pulled away, and water temperature also decreases.And the also source of our deicing system institute calorific requirement just of these heats, when blower fan reverses, the air of high temperature is not directly taken away in the tower, but depressed to diffusion all around by wind-force, hot blast can be discharged to outside the tower through shutter, similar employing hair dryer purges icicle in the tower, thereby reaches good deicing effect, can remove the ice curtain that generates in the cooling tower.This automatic deicing control system adopts double-speed motor to cooperate the electric control loop of band double speed and reverse function, by corresponding control programs, makes blower fan of cooling tower can finish the task of automatic de-icing.
Machine system double-speed motor power loop and control loop circuit diagram are not advanced for machine is other in Fig. 1～4, can satisfy 3 kinds of methods of operation of blower fan of cooling tower: the operation of a. high-speed cruising b. low cruise c. low speed and reverse.High-speed cruising reduces water temperature with the air quantity that low cruise can produce different sizes, and low speed and reverse then is the deicing special use.
The cooling tower automatic deicing control system, mainly form by electric control loop and automatic control program two parts:
(1) electric control loop: the hardware environment that is whole system.As shown in drawings, according to the requirement of heat exchange, blower fan of cooling tower generally adopts double-speed motor, divides at a high speed and low speed.At this motor is on the basis of double-speed motor, and we design the electric control loop that has high-speed cruising, low cruise, low speed and reverse operation function, can satisfy simultaneously by the machine, the function of centralized operation switches.
It comprises double-speed motor, MCC (Motor Control Center, Electric Machine Control center) switch board, PLC (programmable logic controller (PLC)) cabinet, HMI (man-machine interface), execute-in-place case.
The annexation of each parts is: all electrical controls and protecting component have been installed in the MCC switch board, and K01～04 is the operation contactor, and function is as follows separately for it: when K01 is closed, and low cruise; When K02 and K03 are closed, high-speed cruising; When K04 was closed, the low speed and reverse operation had the electrical interlocks function between each running status, had avoided a plurality of contactors while closures and damage equipment.On-the-spot selector switch, button, indicator lamp etc. are installed in the execute-in-place case, are convenient at the scene double-speed motor be operated.Selector switch can to by the machine, centralized operation switches, and when maintenance or on-the-spot emergency, selector switch is threaded to the other operation of machine, this moment, blower fan of cooling tower was in the other manual state of a control of machine fully, not influenced by any of PLC equipment and program.When selector switch is threaded to centralized operation, blower fan of cooling tower can carry out operations such as manual start and stop, automatic de-icing on HMI.
(2) automatic control program: generally just need carry out deicing operation in the season of cold every 24 hours.Do not need human intervention for the purpose that reaches automatic de-icing, use the logic control program of PLC to finish automatic control task.When after selecting the automatic de-icing pattern on the HMI, program flow diagram as shown in Figure 5.
Generally, double-speed motor the state of counter-rotating before the deicing nothing more than in high-speed cruising, low cruise, stop three kinds of states.For avoiding that double-speed motor is caused damage, we switch and directly switch can not be at motor rotation the time carrying out rotating, and must shut down earlier and could change the direction startup through the motors such as delay of certain hour again after static fully.When preparation beginning deicing is finished in the program timing; can detect earlier present motor is in which kind of duty (low speed or stop) at a high speed, and notes this duty; it is (at a high speed different with the time of repose of low speed then to shut down and leave standstill the back that remains static fully as motor in operation; can set according to actual conditions); open motor to low speed and reverse, the beginning deicing.Program autostop after deicing in about 30 minutes is finished, and on request motor is switched to former duty.This program is the Automatic Control program, does not need to think intervention fully.After using this control system, only need selected automatic de-icing mode of operation on HMI (actual effect can be come on-the-spot the adjustment by setting the blower fan reversing time), the freezing various influences that cause just can be eliminated by system.It is the damage of making a hole in the ice and may cause equipment that the people had both been avoided in the application of this cover system, has saved manpower and materials, can also prevent from freezing equipment to be caused a series of influences.Compare with other technologies on the market, this programme is simple, and the deicing effect is comparatively obvious, efficiently solves the situation that winter, exclusive blower fan of cooling tower blade seriously froze, and has improved the effect and the reliability of cooling tower self-operating.
Be described in further detail the utility model below in conjunction with embodiment.
As shown in Figure 1, automatic deicing control system of cooling tower fan comprises double-speed motor M, MCC switch board and PLC; Three-phase electrical source of power (alternating current 380V, phase line L1, L2, L3) is connected to double-speed motor M, and its power loop is equipped with current transformer Ta, Tc and Ta1, Tc1, and the corresponding cashier's office in a shop ammeter that is equipped with of MCC can show running current cashier's office in a shop at MCC.Electric Machine Control can be divided into the other and concentrated two kinds of control modes of machine, and the other control box of machine is installed in device context, moves by the button control motor on the control box; HMI is placed on the control room, by the operation of PLC control motor.
Three phase line L1, L2 of three-phase electrical source of power, L3 are divided into three the tunnel after by circuit breaker Q 01, and the first via is that contactor K01 often leaves main contact and is connected to double-speed motor M (earth connection PE, three- phase 1U, 1V, 1W), the control low cruise; The second the tunnel is that contactor K04 often leaves main contact and is connected to double-speed motor M (earth connection PE, three- phase 1U, 1V, 1W), the operation of control low speed and reverse; Third Road is controlled by K02 and two contactors of K03 and is realized, contactor K02 often leaves main contact and is connected to double-speed motor M (earth connection PE, three- phase 2U, 2V, 2W), the K03 contactor is closed simultaneously realizes that the motor internal wiring becomes Y-Y connection by delta connection, thereby realizes the high-speed cruising control of motor.Contactor K01 often leaves main contact and is connected to double-speed motor M and contactor K02 and often opens on the two-way powered wire that main contact is connected to double-speed motor M and also be connected to current transformer T respectively
a, T
cAnd T
a1, T
c1, the two ends of contactor K01 are connected to the reverse contactor K04 of three-phase and often open main contact, and contactor K01 often leaves and also is connected to the contactor K03 that three-phase is connected together between main contact and the double-speed motor M and often opens main contact.Current transformer T
a, T
cAnd T
A1, T
C1Be connected to the MCC switch board by electrothermal relay F01 thermal element, ammeter PA and electrothermal relay F02 thermal element, ammeter PA1 respectively.
Be installed in current transformer Ta, Tc on the power loop and Ta1, the Tc1 electric current after with conversion and send into electrothermal relay F01 thermal element, ammeter PA and electrothermal relay F02 thermal element, ammeter PA1 respectively, reach the purpose that overload protection and electric current show.
As shown in Figures 2 and 3, two line traffic control power supply (alternating current 220V, phase line L, zero line N) is connected to the MCC switch board by circuit breaker Q 11, comprises low cruise control loop, low speed and reverse operation control loop, high-speed cruising control loop, winding switching controls loop, low speed SBR control loop, high speed SBR control loop, Fault Control loop, indicating fault control loop in the MCC switch board, stop to indicate control loop, low cruise to indicate control loop, low speed and reverse operation indication control loop and high-speed cruising indication control loop.
Be connected between two lines of two line traffic control power supplys:
Chuan Lian relay K 10 normally closed interlocks, the normally closed auxiliary contact of contactor K03, relay K 11 normally open contacts, K22 normally closed interlock successively; Be connected to the execute-in-place case then, at first be button S3 by the band normally closed interlock, be divided into three the tunnel then, one the tunnel is connected to contactor K01 often opens auxiliary contact, another road is connected to the contact 1,2 of universal seclector S6 and the button S1 of band normally open contact, Third Road is connected to contact 5,6 and relay K 20 normally open contacts of universal seclector S6, this three the tunnel converge after more successively by the auxiliary normally closed interlock of contactor K04, contactor K01 coil, this loop is as the low cruise control loop;
Drawing a branch road between the button S3 of the band normally closed interlock in the low cruise control loop and the contact 5 of universal seclector S6 is connected to contactor K04 and often opens auxiliary contact, draw the button S2 that a branch road is connected to the band normally open contact between the button S1 of the contact 2 of universal seclector S6 and band normally open contact, draw a branch road between the contact 6 of universal seclector S6 and relay K 20 normally open contacts and be connected to relay K 21 normally open contacts, after converging, pass through these three branch roads the normally closed auxiliary contact of contactor K01 more successively, contactor K04 coil, control loop is moved as low speed and reverse in this loop;
Button S5, the universal seclector S6 of the button S4 of the button S3 of the button S2 of the button S1 of band normally open contact, band normally open contact, band normally closed interlock, band normally open contact, band normally closed interlock are positioned at the execute-in-place case;
Draw a branch road between the normally closed auxiliary contact of contactor K04 of high-speed cruising control loop and the contactor K02 coil and be connected to contactor K03 coil, this loop is as winding switching controls loop;
Chuan Lian circuit breaker Q 01 auxiliary contact OF, electrothermal relay F01 normally closed interlock, relay K 11 coils successively, this loop is as the lower-speed state control loop;
Draw a branch road between the circuit breaker Q 01 auxiliary contact OF of lower-speed state control loop and the electrothermal relay F01 normally closed interlock, this branch road is connected to electrothermal relay F02 normally closed interlock, relay K 12 coils successively, and this loop is as the fast state control loop;
The normally closed auxiliary contact of contactor K01, the normally closed auxiliary contact of K02, the normally closed auxiliary contact of K04 of series connection are connected to indicator lamp H1 and H2 in parallel then, and this loop is as stopping to indicate control loop;
Contactor K01 often leaves auxiliary contact and is connected to indicator lamp H2 and H3 in parallel, and control loop is indicated as low cruise in this loop;
Contactor K04 often leaves auxiliary contact and is connected to indicator lamp H3 and H4 in parallel, and this loop is as low speed and reverse operation indication control loop;
The contactor K02 of series connection often leaves auxiliary contact, K03 and often opens auxiliary contact, is connected to indicator lamp H4 and H5 in parallel again, and control loop is indicated as high-speed cruising in this loop;
Indicator lamp H1, H2, H3 and H4 are positioned at the execute-in-place case.
As shown in Figure 4, PLC comprises two modules (Siemens PLC C input/output module-ASI module) ASI1 and ASI2.NC1 among the figure～normally closed pin of 3 expressions, C1～3 expression common pin, pin is often opened in NO1～3 expressions, IN1～4 expression signal input pins.
The pin 14 and 15 of modules A SI1 is connected to relay K 20 coils, pin 17 and 18 is connected to relay K 21 coils, pin 19 and 20 is connected to relay K 22 coils, be connected to relay relay K 10 normally open contacts between the pin 2 and 8, be connected to contactor K01 between the pin 3 and 9 and often open auxiliary contact, be connected to contactor K04 between the pin 5 and 11 and often open auxiliary contact, the contactor K02 that is connected to series connection between the pin 6 and 12 often opens auxiliary contact, K03 and often opens auxiliary contact;
The pin 8 and 9 of modules A SI2 is connected to relay K 23 coils, and pin 10 and 11 is connected to relay K 24 coils, is connected to relay K 11 normally open contacts between the pin 5 and 2, is connected to relay K 12 normally open contacts between the pin 6 and 3.
As shown in Figure 5, the using method of automatic deicing control system of cooling tower fan may further comprise the steps:
1) after the timer of PLC is finished the preparation of deicing, begins to detect the blower fan duty, be divided into high-speed cruising, low cruise and stop three kinds of states;
2) if high-speed cruising is then shut down and delayed time a period of time, enter next step then; If low cruise is then shut down and delayed time a period of time, enter next step then; If halted state then directly enters next step;
3) described control system is carried out the low speed and reverse deicing, enters next step after continuing for some time;
4) described control system is shut down, and enters next step after time-delay a period of time;
5) described control system is switched to former duty, begin next step then;
6) timer of PLC is waited for deicing next time, returns step 1).
Be described in further detail its using method below.
At first with circuit breaker Q 01, Q11 main contact closure, system switches on; Enter step 1) then;
The method of step 1) system high-speed operation is divided into centralized operation and the other operation of machine; The method of centralized operation is: the contact 11,12 of universal seclector S6 is connected, with relay K 23 coil electricities of PLC modules A SI2, if must stop then relay K 24 coil electricities with PLC modules A SI2; The other method of operating of machine is: the contact 7,8 of universal seclector S6 connected, then will be with the button S4 closure of normally open contact, and if must stop then button S4 to be disconnected, the shutdown delay time of high-speed cruising is 600s.
The method of system's low cruise is divided into centralized operation and the other operation of machine; The method of centralized operation is: the contact 5,6 of universal seclector S6 is connected, with relay K 20 coil electricities of PLC modules A SI1, if must stop then relay K 22 coil electricities with PLC modules A SI1; The other method of operating of machine is: earlier the contact 1,3 of universal seclector S6 connected, again will be with the button S1 closure of normally open contact, and if must stop then button S1 to be disconnected, the shutdown delay time of low cruise is 300s.
Step 2) method of low speed and reverse operation is divided into centralized operation and the other operation of machine; The method of centralized operation is: the contact 5,6 of universal seclector S6 is connected, with relay K 21 energisings of PLC modules A SI1, if must stop then relay K 22 coil electricities with PLC modules A SI1; The other method of operating of machine is: the contact 1,2 of universal seclector S6 is connected, again with button S2 closure, if must stop then button S2 to be disconnected.
The duration of step 3) low speed and reverse deicing is 1800s.
It is 300s that step 4) is shut down delay time.
Claims (6)
1. automatic deicing control system of cooling tower fan, it is characterized in that: it comprises double-speed motor M, MCC switch board and PLC; The three-phase electrical source of power is connected to double-speed motor M, also is connected to the MCC switch board by current transformer on its motor circuit, is connected to the execute-in-place case on the MCC switch board, and The whole control system also is connected to PLC.
2. control system according to claim 1, it is characterized in that: three phase line L1, L2 of three-phase electrical source of power, L3 are divided into two-way after by circuit breaker Q 01, the contactor K01 of leading up to often opens main contact and is connected to double-speed motor M, another road is often opened main contact by contactor K02 and is connected to double-speed motor M, also is connected to current transformer T on this two-way powered wire respectively
a, T
cAnd T
a1, T
c1, the two ends of contactor K01 are connected to the reverse contactor K04 of three-phase and often open main contact, and contactor K01 often leaves and also is connected to the contactor K03 that three-phase is connected together between main contact and the double-speed motor M and often opens main contact.
3. control system according to claim 1 and 2 is characterized in that: current transformer T
a, T
cAnd T
A1, T
C1Be connected to the MCC switch board by electrothermal relay F01 thermal element, ammeter PA and electrothermal relay F02 thermal element, ammeter PA1 respectively.
4. control system according to claim 1 and 2, it is characterized in that: two line traffic control power supplys are connected to the MCC switch board by circuit breaker Q 11, comprise low cruise control loop, low speed and reverse operation control loop, high-speed cruising control loop, winding switching controls loop, low speed SBR control loop, high speed SBR control loop, Fault Control loop, indicating fault control loop in the MCC switch board, stop to indicate control loop, low cruise to indicate control loop, low speed and reverse operation indication control loop and high-speed cruising indication control loop.
5. control system according to claim 4 is characterized in that being connected between two lines of two line traffic control power supplys:
Chuan Lian relay K 10 normally closed interlocks, the normally closed auxiliary contact of contactor K03, relay K 11 normally open contacts, K22 normally closed interlock successively; Be connected to the execute-in-place case then, at first be button S3 by the band normally closed interlock, be divided into three the tunnel then, one the tunnel is connected to contactor K01 often opens auxiliary contact, another road is connected to the contact 1,2 of universal seclector S6 and the button S1 of band normally open contact, Third Road is connected to contact 5,6 and relay K 20 normally open contacts of universal seclector S6, this three the tunnel converge after more successively by the auxiliary normally closed interlock of contactor K04, contactor K01 coil, this loop is as the low cruise control loop;
Drawing a branch road between the button S3 of the band normally closed interlock in the low cruise control loop and the contact 5 of universal seclector S6 is connected to contactor K04 and often opens auxiliary contact, draw the button S2 that a branch road is connected to the band normally open contact between the button S1 of the contact 2 of universal seclector S6 and band normally open contact, draw a branch road between the contact 6 of universal seclector S6 and relay K 20 normally open contacts and be connected to relay K 21 normally open contacts, after converging, pass through these three branch roads the normally closed auxiliary contact of contactor K01 more successively, contactor K04 coil, control loop is moved as low speed and reverse in this loop;
Relay K 10 normally closed interlocks, draw a branch road between the normally closed auxiliary contact of contactor K03, again successively by relay K 12 normally open contacts, the K24 normally closed interlock, be divided into three the tunnel behind the button S5 of band normally closed interlock, one the tunnel is connected to contactor K02 often opens auxiliary contact, another road is connected to the contact 7 of universal seclector S6 successively, 8 and the band normally open contact button S4, Third Road is connected to the contact 11 of universal seclector S6 successively, 12 and relay K 23 normally open contacts, this three the tunnel converge after more successively by the normally closed auxiliary contact of contactor K01, the normally closed auxiliary contact of contactor K04, contactor K02 coil, this loop is as the high-speed cruising control loop;
Button S5, the universal seclector S6 of the button S4 of the button S3 of the button S2 of the button S1 of band normally open contact, band normally open contact, band normally closed interlock, band normally open contact, band normally closed interlock are positioned at the execute-in-place case;
Draw a branch road between the normally closed auxiliary contact of contactor K04 of high-speed cruising control loop and the contactor K02 coil and be connected to contactor K03 coil, this loop is as winding switching controls loop;
Chuan Lian circuit breaker Q 01 auxiliary contact OF, electrothermal relay F01 normally closed interlock, relay K 11 coils successively, this loop is as the lower-speed state control loop;
Draw a branch road between the circuit breaker Q 01 auxiliary contact OF of lower-speed state control loop and the electrothermal relay F01 normally closed interlock, this branch road is connected to electrothermal relay F02 normally closed interlock, relay K 12 coils successively, and this loop is as the fast state control loop;
Circuit breaker Q 01 Alarm contactor SD, electrothermal relay F01 normally open contact, electrothermal relay F02 normally open contact in parallel are connected to relay K 10 coils after these three branch roads converge again, and this loop is as the Fault Control loop;
Relay K 10 normally open contacts, the indicator lamp H1 of series connection, this loop is as the indicating fault control loop;
The normally closed auxiliary contact of contactor K01, the normally closed auxiliary contact of K02, the normally closed auxiliary contact of K04 of series connection are connected to indicator lamp H1 and H2 in parallel then, and this loop is as stopping to indicate control loop;
Contactor K01 often leaves auxiliary contact and is connected to indicator lamp H2 and H3 in parallel, and control loop is indicated as low cruise in this loop;
Contactor K04 often leaves auxiliary contact and is connected to indicator lamp H3 and H4 in parallel, and this loop is as low speed and reverse operation indication control loop;
The contactor K02 of series connection often leaves auxiliary contact, K03 and often opens auxiliary contact, is connected to indicator lamp H4 and H5 in parallel again, and control loop is indicated as high-speed cruising in this loop;
Indicator lamp H1, H2, H3 and H4 are positioned at the execute-in-place case.
6. control system according to claim 1 and 2 is characterized in that: PLC comprises PLC input/output module ASI1 and ASI2;
The pin 14 and 15 of modules A SI1 is connected to relay K 20 coils, pin 17 and 18 is connected to relay K 21 coils, pin 19 and 20 is connected to relay K 22 coils, be connected to relay relay K 10 normally open contacts between the pin 2 and 8, be connected to contactor K01 between the pin 3 and 9 and often open auxiliary contact, be connected to contactor K04 between the pin 5 and 11 and often open auxiliary contact, the contactor K02 that is connected to series connection between the pin 6 and 12 often opens auxiliary contact, K03 and often opens auxiliary contact;
The pin 8 and 9 of modules A SI2 is connected to relay K 23 coils, and pin 10 and 11 is connected to relay K 24 coils, is connected to relay K 11 normally open contacts between the pin 5 and 2, is connected to relay K 12 normally open contacts between the pin 6 and 3.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009203532476U CN201740451U (en) | 2009-12-29 | 2009-12-29 | Automatic deicing control system for fan of cooling tower |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009203532476U CN201740451U (en) | 2009-12-29 | 2009-12-29 | Automatic deicing control system for fan of cooling tower |
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| Publication Number | Publication Date |
|---|---|
| CN201740451U true CN201740451U (en) | 2011-02-09 |
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|---|---|---|---|
| CN2009203532476U Expired - Fee Related CN201740451U (en) | 2009-12-29 | 2009-12-29 | Automatic deicing control system for fan of cooling tower |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106522147A (en) * | 2016-09-08 | 2017-03-22 | 李俊杰 | Automatic deicing device for cooling tower |
-
2009
- 2009-12-29 CN CN2009203532476U patent/CN201740451U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106522147A (en) * | 2016-09-08 | 2017-03-22 | 李俊杰 | Automatic deicing device for cooling tower |
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