JPH0222320B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a cooling tower blower device for fully automatically controlling the mechanical speed change of a blower fan as a load with a large moment of inertia.

[Prior art]

Conventionally, it has been considered to apply a mechanical transmission as a method of driving a blower fan, but none of them have reached practical use.

An example of this is disclosed in Japanese Patent Application Laid-Open No. 54-67251.

FIG. 1A shows its configuration diagram. In the figure, a cooling tower is shown.
2 is a water sprinkler, 3 is a filling material, 4 is a water tank, 5 is an inlet pipe for cooling water, 6 is an outlet pipe, and 7 is an air flow.
The principle is that heated cooling water is sprayed by a sprinkler 12, cooled by an air flow 7 from below, and then returned to the outlet 6. This is intended to control the speed of the blower in order to continuously change the amount of airflow 7.

10 is a stepless reducer, 11 is a blower motor, 12 is a gear reducer, 13 is a blower fan, 14 is a power source, 1
5 is a computer, and 16 is a sensor.

Here, the processing is performed by the computer 15 and a speed change signal is given to the stepless reducer 10 to control the rotational speed of the blower fan 13.

〔problem〕

Although those skilled in the art have come up with this type of idea many times in the past, all of them have remained beyond ideas, failed to put them into practical use, and have not been commercialized.
The reason for this was mainly due to the following two points.

The first reason is that the transmission part will be damaged in a short period of time because the continuously variable reducer 10 cannot withstand a large inertial load such as a blower fan, and the second reason is that the transmission part will be damaged in a short period of time. The problem was that no solution could be found as to whether the configuration should be automatically controlled.

For example, the description will be made using a conventionally well-known stepless reduction gear 10. FIG. 1B is a sectional view of a metal friction type transmission, which is an example of a static friction drive system. In this figure, only a cross-sectional view of the half side from the axis center is drawn. In the figure, A is the input shaft, B is the output shaft, C is the sun wheel, and the fixed side car C ₁ and the moving side car C ₂ constantly sandwich the planet wheel E with the spring D, while the planet wheel E and the carrier F are interlocked. do. G is a gear ratio control unit, which is sandwiched between a fixed ring _G2 and a moving cam _G1 , and enables the planetary wheel E to move in the radial direction. In this structure, the planet wheel E plays the role of a variable planet, and the gear ratio is controlled by the interval between the cracks by operating the moving cam _G1 .

However, when this type of friction transmission method between metal wheels C and E is applied to a large inertial load such as a blower,
The following phenomenon occurs.

In a blower, when transmitting power from input shaft A to output shaft B, in a planetary wheel, point Z is the fulcrum and contact point X
is rotated in the connection direction, thereby extracting output from the Y point, so torque is transmitted smoothly by the viscous drag in the lubricating oil. However, on the contrary, with a large inertia load, when the main motor 11 is stopped, or even if it is not stopped, especially when moving vehicle _G1 is operated to the deceleration side,
Since inertia remains on the load side, power transmission is not normally performed, but power is transmitted from the output shaft B side to the input shaft A side. During this reverse transmission, the planetary wheel E has its fulcrum as the Z point and the Y point as the point of action, so the original transmission point, the X point, receives an irregular external force, and as a result, the viscous transmission by the lubricating oil is not properly carried out. Does not work, planetary wheel E
Damage occurred instantaneously to each metal contact surface of the sun wheel C, and as this was repeated, it became scrap in a short period of time.

Furthermore, in addition to the inherent drawbacks of this continuously variable reducer 10, there is a second reason why the continuously reduced reducer 11
Mechanical speed change control of the blower has not been carried out because the technology for controlling the speed ratio of the blower has not yet been established.

〔the purpose〕

This invention solves the above-mentioned drawbacks by using an accelerating/decelerating type belt speed reducer as a power transmission method using line or surface contact using a belt, instead of transmitting power through point contact between metals as described above. Moreover, it is an object of the present invention to provide a cooling tower blower device that can be put to practical use by automatically controlling the speed ratio using a servo adjustment system.

[Technical means to solve problems]

In the present invention, in order to sandwich the speed change belt between fixed and sliding pulleys, a pulley device consisting of a pair of pulleys is attached to an input shaft and an intermediate shaft and housed in a single frame, and the input shaft is connected to a blower motor. The input shaft side pulley device is installed against a spring provided on the intermediate shaft side pulley device and installed on the frame body so as to engage with the coupled speed-up/deceleration type belt transmission and the input shaft side pulley device. Stable automatic control operation of the blower fan is achieved by the configuration of a pilot electric controller having a reversible electric motor for sliding, and a servo controller connected to the pilot electric controller and supplying an electric variable speed proportional output. In particular, the servo controller is connected to a cooling water temperature detector in an input circuit and to the pilot electric controller in an output circuit for increasing or decelerating commands, and further connects the reversible motor to the input circuit via a transmission device. This is a feedback circuit that is linked to each other.

[Effect]

According to this configuration, even when applied to a blower fan with large inertia, when the main motor is stopped or when a command is issued to the deceleration side during operation, the above-mentioned reaction is generated from the output shaft side via the belt. is applied to the input shaft, but at this time the belt itself slips against the pulley, but the elasticity of the belt material (synthetic rubber) momentarily absorbs this reaction, resulting in wear of the material itself. However, there is no damage to the basic mechanical structure.

[Embodiment] FIG. 2 shows a partial sectional view of a double suction type cross-flow cooling tower 10 as an embodiment. In the figure, 11 is a water tank, 12 is an air inlet louver, 1
Reference numeral 3 indicates a filler, 14 an eliminator, and 15 a partition wall. Cooling water is supplied from an inlet pipe 17 to a water sprinkling tank 16 above these. Further, a cylindrical fan tuck 24 is installed in the center, and an air outlet 20 is provided at the top of the cylindrical fan tuck 24, between which a blower fan 21 and a gear reducer 22 are installed in the center of a pipe stay 23 that is radially incorporated. Ru.

Furthermore, the top plate 2 adjacent to the fan stack 24
5 includes an induction motor 27, a pilot electric controller 29, and these electric motors 27 and controllers 29.
A variable power mechanism 26 is installed, which is comprised of an increase/decrease type belt transmission 28 which is integrally assembled with a variable power mechanism 26.
Further, the rotational output of the transmission 28 is coupled to the gear reducer 22 by a coupling 30 and a transmission body 31. In addition, the transmission 28 has a mechanism in which the air is circulated through the closed chamber of the transmission 28 from the cooling air inlet 35 through the piping 36 and then released from the exhaust port 37 in order to prevent frictional heat between the belt and the pulley. This is aimed at improving the belt life rate. 40 and 41 are wiring for power supply and control signals.

FIG. 3 is a configuration diagram of the speed-up/down type belt transmission 28. As shown in FIG. This transmission 28 includes a frame body 45 and a lid body 46.
A sealed chamber is formed to prevent moist air from entering, and the motor rotation shaft, that is, the input shaft 51 is located inside.
Fixed pulleys 54a and 55a for holding the speed change belt 53 are provided on the intermediate rotating shaft 52 and the intermediate rotating shaft 52, respectively.
A pair of pulley devices 54 and 55 consisting of sliding pulleys 54b and 55b are attached. The drive-side pulley device 54 includes an impeller 56b attached to a sliding pulley 54b, and a spiral casing 56a.
A vortex centrifugal blow device 56 consisting of a casing 56a is attached, and a portion of the casing 56a communicates with the pipe 36', which in turn communicates with the introduction pipe 36 shown in FIG.
This introduces heat-insulated air into the room, and
It is discharged from 7. Pilot electric controller 2
9 is connected to an adjusting hoisting screw 57, and as the adjusting hoisting screw 57 rotates in the forward or reverse direction, the guide ring 58 moves up and down, thereby causing the fixed pulley 54a to move up and down.
The gear ratio is controlled by adjusting the distance between the sliding pulley 54a and the sliding pulley 54a. A reversible electric motor 79, an adjustment hoisting screw 57, and a guide ring 58, which are interposed between the pilot electric controller 29 and the pulley device 54, perform an electrical/mechanical signal conversion function in the servo adjustment system.

That is, when the contact radius between the pulley device 54 and the variable belt 53 changes, the contact radius also changes on the driven side, which is simply held by the spring force, and the gear ratio is controlled by this cooperative operation. be done.
For belt replacement and maintenance, the intermediate shaft 52 is cantilever-supported by two bearings 59a and 59b, with one end being a free end, and the lid 46 is separable from the frame 45. The shaft support 60 has an adjustment mechanism using a bolt 62 and an elongated hole 6 so that it can be slid with respect to the frame 45.
1.

In the present invention, as described above, the first stage transmission is combined with an increasing/decelerating type belt transmission, and the second stage is combined with a constant reduction ratio speed reducer. Here, the increasing/decelerating type belt transmission is one that can change the speed of the intermediate shaft 52 both in the direction of increasing the speed and in the direction of decelerating the input rotation speed of the electric motor. Therefore, it is different from a continuously variable reducer that can only change speed in the direction of deceleration in response to input.

It has been found that such a combination of an increase/decrease type belt transmission and a speed reducer has the following synergistic effect, and works as a sufficiently stable and advantageous transmission even with a load of large inertia.

First, with a large inertial load, even if the large inertial power of the load is reversely transmitted when a deceleration command is issued from the pilot electric controller during operation, the elastic force of the belt itself and the spring of the driven pulley device It has the advantage of being able to relieve stress through the three actions of relief and slip between the belt and pulley, and this guarantees durability when continuously operating a large inertial load.

Second, in the combination of an increasing/decelerating type transmission and a reducer,
Particularly in the speed increase region, once the pulley devices 54 and 55 increase the input rotation speed, the speed reducer 2
Although it may seem like a waste of time to decelerate the speed in step 2, this has an advantageous effect on making the equipment smaller, more economical, and easier to maintain.

From the first point, when the electric motor 27 is stopped, the contact number 4R is stopped, as is clear from FIG. 4, so the pilot electric controller 29 is also stopped (described later). Therefore, the rotating force in the opposite direction applied from the blower fan 21 via the reducer 22 is simply the belt 5
However, when deceleration is commanded during operation, the fan maintains the high-speed inertia before the command, and on the other hand, the pilot electric controller 29 forcibly rotates the rotor of the electric motor 27. The electric motor 29 also applies a large rotational force to the input pulley 54 while acting on the input pulley 53 together with the spring 55c. Therefore, the speed stress between the high-speed inertia force of the load before the command and the rotational force of the electric motor is inevitably applied directly to the line or surface contact portion of the belt and pulley even in this case. In this case, the elastic force of the belt transmission, which is mainly made of synthetic rubber such as neoprene, absorbs this stress, and if this stress cannot be absorbed further, the pulley
Even if a slip occurs between the belt and the pulley due to the escape of the spring 55c, and the belt material wears out, this speed stress is absorbed. This is fundamentally different in principle from the metal friction reducer mentioned above, and the present invention does not involve a situation that would cause damage to the metal transmission wheel itself.
The warranty function takes advantage of the fact that the belt is a consumable item.

Furthermore, as a second advantageous condition, miniaturization and economy can be achieved. In other words, as a characteristic of the blower fan itself, its shaft horsepower W is proportional to the cube of the rotation speed N, and maximum power is required at maximum speed increase.
The capacities of the belt transmission and speed reducer may be selected based on the transmitted horsepower at this time. In other words, in a normal belt transmission, if the transmitted horsepower Wo is constant, the horsepower is proportional to the product (N・T) of the rotation speed N and belt tension T, so if a transmission that acts as a speed increaser is used, the rotation Since the number N is large, the tension T applied to the belt can be reduced accordingly. This means that the first stage transmission can use extremely small and inexpensive belts and pulleys. This has a great economic effect because it is placed on the top of the tower, which simplifies the structure of the tower itself and facilitates maintenance.

FIG. 4 is a block circuit connection diagram of the automatic cooling water temperature control and adjustment device. A temperature detector 67 is provided at a cooling water outlet 65 of the cooling tower 10 and connected to a servo regulator 70 . The servo controller 70 includes a bridge input circuit 71, an operational amplifier 72, and a filter 7.
3. Operational amplifier 74, positive feedback circuit 75, dead band circuit 76, speed increase and deceleration side output switch circuit 77
and 78. Further, the output switch circuits 77 and 78 have their contacts 77a
and the pilot electric controller 29 via 78a.
It is connected to the. On the other hand, the pilot electric controller 29 is connected to an input shaft side pulley device 54 in the speed-up/down type belt transmission 28. The cooling water temperature detector 67, the servo regulator 70, the pilot electric controller 29, the belt transmission 28, the speed reducer 22, and the blower fan form a first feedback circuit. Power supplies 8' and T' to the pilot electric controller 29 having the reversible motor 79 are supplied from the S and T terminals of the three-phase power supply line 83 to the blower motor 27. On the other hand, this power line 8
3 includes a start/stop control circuit 80 and a low temperature section control circuit 8.
1 is connected.

The operation of this servo adjuster 70 is as follows. When the start switch SW is pressed, normally closed contact 2R
2, the relay 3R is operated, and the contact 3R1 is self-held, and the power to the servo regulator 70 (not shown) is turned on, and the servo regulator 70 is operated, but the pilot electric controller 29 has the contact 4R2 open. It doesn't work because it is. Next, while the temperature of the cooling water is maintained within the proportional operation region of the servo controller 70, the contact of the mechanical temperature detector 68 for low temperature region control is closed, so the low temperature region control is controlled. The circuit 81 is activated when the contact 3R1 is closed, and at this time, the contact 3R2 is closed and the relay 4R is energized. Therefore, the blower motor 27 operates via the three contacts 4R1. At the same time, interlock contact 4R2
When the valve is closed, the pilot electric controller 29 operates and performs normal proportional control operation. As is clear from FIGS. 3 and 4, the pilot electric controller 29 has a built-in reversible electric motor 79 and a gear reducer, and a part of the electric motor 79 rotates the hoisting lead 58 in the normal or reverse direction according to the signal from the servo regulator 70. The speed change pulley 54
It is used to control the speed change by moving the sliding pulley 54b against the spring 55c. Further, this electric motor 79 also has a transmission device, that is, a gear reduction gear, in conjunction with a pre-switch circuit 71.
1, the state of the speed change ratio is detected by a variable resistor, and a second feedback circuit of the servo adjustment system is configured to arbitrarily control the fan rotation speed.

Although an example is shown in which the adjustment hoisting lead 57 is installed on the pulley device 54, other types may be used, and the adjustment hoisting lead 57 may be integrated with the reversible motor 79.

At this time, if the outside air wet bulb temperature is constant, the rotation speed of the fan will increase as the cooling water temperature rises, but even if the high limit switch HL of the pilot electric controller 29 closes, the fan will increase to the maximum speed. Operates continuously at high speed. Also, when the cooling water temperature drops, even if low limit switch LL closes and relay 1R closes, relay 3R still has contact 2.
Since it is excited by R2, the speed wind motor 2
7 continues to rotate, and the blower fan 21 rotates at the lowest speed.

At this time, when the cooling water temperature drops further as in winter, the liquid-filled inlet water or outlet water temperature detector 68 is activated, the relay 4R is deenergized, and the main motor 27 can be stopped. ing. That is, when the cooling water temperature is within the proportional band range of the servo controller 70, the fan rotation speed is proportionally controlled according to the temperature, and when the temperature falls below the proportional band range, automatic start/stop control of the main motor 27 is performed. It is configured so that it can be switched.

Next, to completely stop this device, press the stop switch SW, energize relay 2R, and contact 2R.
1 and 2R2 are inverted, and at the same time, the contacts of the bridge input circuit 71 of the servo regulator 70 (not shown)
, and sends out a signal that causes only the deceleration output switch circuit 78 to operate. Then, the pilot electric controller 29 receives this deceleration command and eventually lowers the speed.
Limit switch LL is closed, relay 1R is deenergized, contact 1R1 is opened, relay 3R is deenergized, regulator 70 stops operating, and relay 4R is stopped via contact 3R2. That is,
The start/stop control circuit 80 performs slow start control in this way, and when stopped, the belt 53 is stopped at its maximum deceleration, achieving ease of maintenance, and at the same time, at the next restart, the blower fan is always at the lowest In other words, the engine is started from the lightest load state based on the principle of the power cube reduction law mentioned earlier. For this reason, there is an advantage that auxiliary equipment such as a reactor starter is not required, especially for re-starting. Note that the slow start control performed in the start/stop control circuit 80 and the blow device 56 described above are both mere belt protection measures; the former is for relieving the belt impact at the time of start, and the latter is for preventing friction. This is a measure to prevent cutting due to softening of the belt material due to heat, and is merely an auxiliary measure to improve durability toward full automation, which is the gist of the present invention, and is not directly related to the gist of the invention.

[Other Examples]

FIG. 5 is a partial configuration diagram of a cooling tower blower system according to another embodiment of the present invention, in which a belt reducer 85 is added to the reducer 22 shown in FIG. are using. As mentioned earlier, this system has the property that the belt 31' of the reducer 29 also actively absorbs the stress caused by the difference between the rotational force returned from the large inertia load side and the rotational force from the electric motor when a deceleration command is issued. Therefore, it has a better effect against this stress, and has the advantage of reducing wear on the belt of the belt speed change on the acceleration/deceleration side.

[Effects of the present invention]

Conventionally, mechanical speed control has been considered extremely difficult for loads with large inertia such as blower fans, so electric systems such as inverter systems and eddy current motor systems, which have extremely low energy efficiency, have been used. However, in the present invention, by adopting an accelerating/decelerating type belt transmission that can transmit power through line or surface contact between the belt and the pulley, stable power transmission is achieved, and moreover, it is more efficient than the electric type. An ideal, inexpensive and highly efficient purely mechanical transmission can be achieved. On the other hand, by assembling a pilot electric controller to this speed-up/down type belt transmission and adjusting it with a servo adjustment system, it becomes possible to control the gear ratio purely electrically. This means that power transmission is configured mechanically and speed change control is configured electrically, so the advantages of both can be secured independently, resulting in high durability and reliability, and extremely high precision when controlling the temperature of cooling water. Controllability becomes not just an idea but a concrete reality.

Moreover, with large inertia loads, when deceleration control is commanded, the load itself retains the inertia power before the command.
At this time, the difference in rotational force between the electric motor and the load is directly applied as stress to the friction transmission part, but in an increase/deceleration type belt transmission, the action of the spring attached to the pulley, the slip action between the belt and the pulley, and the belt These three characteristics have the advantage of instantly absorbing these stresses, achieving extremely durable power transmission.

Also, when looking at the blower fan as a drive system configuration, the first stage is a speed increase/reduction type transmission that operates as both a speed increaser and a speed reducer, and the second stage is a fixed speed ratio speed reducer. Since the first stage transmission also functions as a speed increaser, a small belt transmission is sufficient to ensure the specified transmission horsepower, and the device itself that uses this is compact and extremely inexpensive variable air volume control. mechanism can be achieved.
Moreover, as a derivative effect of using such a variable air volume control mechanism, power consumption is reduced, and it is also possible to control state quantities such as the temperature of cooling water in a cooling tower with extremely high precision as a control target. Therefore, its industrial value is enormous, as it can achieve high-efficiency operation of refrigerators, etc.

[Brief explanation of drawings]

FIG. 1A shows a configuration diagram when a blower device, which was conventionally considered as a mere idea, is applied to a cooling tower, and FIG. 1B shows a partial cross-sectional view of an example of a stepless reducer used therein. Fig. 2 shows a schematic external view of a cooling tower according to an embodiment of the present invention, Fig. 3 shows a partial sectional view of an increase/decrease type belt transmission used in the cooling tower, and Fig. 4 shows: FIG. 5 shows a wiring diagram of a servo control circuit system for controlling the blower motor and belt transmission for the cooling tower, and FIG. 5 shows a schematic partial configuration diagram of a cooling tower according to another embodiment of the present invention. There is. In the figure, 10... cooling tower, 21... ventilation fan,
22... Constant speed ratio reducer, 27... Main blower motor,
28...Acceleration/deceleration type belt transmission, 29...Pilot electric control machine, 51...Input rotating shaft, 52...
Intermediate rotating shaft, 70... Servo adjustment circuit, 80...
Start/stop control circuit, 81...Low temperature section control circuit.

Claims (1)

[Scope of Claims] 1. A pulley device consisting of a pair of pulleys is attached to an input shaft and an intermediate shaft and housed in a single frame in order to sandwich the speed change belt between fixed and sliding pulleys, and the input shaft is A speed-up/deceleration type belt transmission connected to the blower electric motor, and a belt transmission on the input shaft side that is installed in the frame so as to engage with the input shaft side pulley device against a spring provided on the intermediate shaft side pulley device. A pilot electric controller having a reversible motor that slides the pulley device, a speed reducer coupled to the intermediate shaft and having a blower fan directly connected to the output shaft, and a reducer connected to the pilot electric controller to generate an electrically variable speed proportional output. The servo controller is connected to a cooled temperature sensor through an input circuit and to the pilot electric controller through an output circuit for speeding up or decelerating commands, and further connects the reversible electric motor to the pilot electric controller. A cooling tower blower device comprising a feedback circuit interlocked with the input circuit via a transmission device. 2. The cooling tower blower device according to claim 1, wherein the speed reducer is a belt-based pulley speed reducer. 3. The cooling tower blower device according to claim 1, wherein the speed reducer is a gear speed reducer, and the input shaft of the gear speed reducer and the intermediate shaft are connected by a transmission body. 4. In the cooling tower blower device according to claim 2 or 3, the speed-up/deceleration type belt transmission connects the input shaft from one plane side of the frame body and the intermediate shaft from the other plane side. Derive each
In the cooling tower blower device, the input and intermediate shafts to which the pulley device is attached are formed within the frame with one end being a free end.