JP3290078B2 - Axial-flow blower and damper control method and device therefor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an axial blower and a method and apparatus for controlling the damper, and more particularly, to an axial blower having a plurality of variable-speed axial blowers arranged in parallel and its damper control. Method and apparatus.

[0002]

2. Description of the Related Art Axial blowers are mainly used for tunnel ventilation equipment and thermal power generation equipment. In tunnel ventilation,
As shown in FIG. 5, an axial blower 53 is provided to ventilate exhaust gas discharged from a vehicle 52 passing through a tunnel 51. In such equipment, a plurality of blowers are often arranged in parallel in order to secure a predetermined air volume and to provide a spare in case of a failure. When operating multiple blowers with the same output, basically the same rotation is performed so that the static pressure on the discharge side is the same for both blowers so that backflow from one blower to the other blower does not occur. Driving by number is performed. In addition, when starting a blower that is not operating in a state where some of the blowers are already operating, it is necessary to control the release timing of the discharge-side damper so as not to cause surging. As a conventional method for this purpose, a control method is adopted in which the rotation speed of the blower to be started is increased, and the damper on the discharge side is released at a time when it is considered that the rotation speed will be the same as the rotation speed of the one already in operation. Was.

[0003]

FIG. 4 shows the relationship between the difference between the suction-side static pressure and the discharge-side static pressure (hereinafter simply referred to as static pressure) and the flow path resistance with respect to the air volume when the blower is operating. , Respectively, so-called characteristic curves and resistance curves, respectively. Here, first, two variable-speed axial-flow blowers having the same performance and arranged in parallel are considered. The characteristic curve P (1, N1) shows the relationship between the air volume and the static pressure when only one blower is operating at the rotation speed N1. The resistance curve R indicates the relationship between the flow rate and the flow path resistance of a system including two blowers and the flow path. The pressure Pd at the intersection of the characteristic curve P (1, N1) and the resistance curve R is the operating point static pressure when only one fan is operating at the rotation speed N1. On the other hand, when both blowers are operated at the rotation speed N1, the characteristic curve becomes like the characteristic curve P (2, N1). This curve is obtained by extending the air volume (the value on the horizontal axis) of the characteristic curve P (1, N1) for one vehicle to twice. In the actually employed operating range, the operating point static pressure Pae of the characteristic curve P (2, N1) is designed to be smaller than the valley static pressure Pbe so as not to be unstable.

Here, only one blower is operated at the rotation speed N1, and the other blower, which is not operated, is started to operate, and N2 is increased while trying to increase the rotation speed to the rotation speed N1. Consider a transient state in which the number of rotations has increased. Naturally, N2 <N1. Rotation speed N in this case
The characteristic curve of one blower rotating at 2 is referred to as a characteristic curve P (1, N2). At this time, when the discharge side damper of the fan rotating at the rotation speed N2 is opened, the characteristic curve combined with the blower already operating at the rotation speed N1 is almost equal to the characteristic curve obtained by adding the air volumes of both the blowers. P
(2, N1, N2). When the operating point static pressure Pa of this characteristic curve is larger than the static pressure Pb2 'of the valley, if the discharge-side damper of the blower rotating at the rotation speed N2 is opened, this blower causes surging. .
Therefore, the timing of opening the discharge side damper is always Pa−Pb
2 '<0, but since the static pressure Pb2' of this valley is substantially equal to the static pressure Pb2 of the valley of the characteristic curve P (1, N2), the rotational speed at which the blower started later does not cause surging is set. If N2, the characteristic curve P (2, N1, N
2) The operating point static pressure Pa is

## EQU1 ## It is necessary that Pa <Pb2 is satisfied.

However, in the conventional control method described above, since the rotation speed of the blower is predicted according to time, the release timing of the discharge-side damper is controlled without knowing the actual static pressure value on the discharge side of the flow path. Means that. Therefore, the operating point static pressure Pa in the parallel operation is sufficiently lower than the static pressure Pb2 in the valley of the characteristic curve in the single-unit operation so that the condition of (Equation 1) is satisfied in a wide rotation speed range. We have to make a design with a certainty. To cope with this, the pressure that can be output from each blower is increased to cope with this. However, this has a problem in that the cost of the apparatus is increased.

SUMMARY OF THE INVENTION An object of the present invention is to provide an axial blower and a damper control method for the blower, which are provided with a function for more accurately predicting an operation state so that surging does not occur without imposing extra capacity on the blower. In providing the device.

[0007]

According to the present invention, there is provided a method for controlling a damper of an axial blower having two axial blowers, the method comprising: When operating with the discharge side damper of the blower both open, the operating point static pressure at the junction of the discharge side damper outlet, which is determined according to the rotation speed of each axial blower,
The valley static pressure at the valley of the change characteristic of the static pressure with respect to the air flow at the confluence, which is determined according to the rotational speed when only one axial flow blower is operated, is measured in advance for each rotational speed. The first axial fan of the two axial fans is operated at a first speed, the second axial fan is stopped, and its discharge-side damper is When starting the operation by increasing the rotation speed of the second axial blower from the closed state, the operating point static pressure at that time from the rotation speed of the first and second axial blowers, and The valley static pressure is read from the storage means from the rotational speed of the second axial blower, and the readout of the second axial blower is compared by comparing the read operating point static pressure with the valley static pressure. Axial-flow blower, characterized in that the timing of opening the side damper is determined. It discloses a damper control method.

The present invention is also a damper control device for an axial blower provided with two axial blowers, wherein the operation is performed when both discharge side dampers of the two axial blowers are opened. First storage means for previously measuring and storing the operating point static pressure at the junction of the discharge-side damper outlet, which is determined according to the rotation speed of each axial blower, and only one axial flow A second storage means for previously measuring and storing a valley static pressure in a valley of a valley of a change characteristic of a static pressure at the confluence with respect to an air flow, which is determined according to a rotation speed when the blower is operated; The second axial blower of the two axial blowers is operated at a first speed, the second axial blower is stopped and the discharge side damper is closed, and the second axial blower is closed. Parallel operation that starts operation by increasing the rotation speed of the axial blower First reading means for reading the operating point static pressure at that time from the first storage means from the rotation speeds of the first and second axial blowers at the start; and the second reading means at the start of the parallel operation. A second valley static pressure for reading the valley static pressure from the second storage means from the rotation speed of the axial blower
Timing of opening the discharge-side damper of the second axial-flow blower by comparing the operating point static pressure and the valley static pressure read by the first reading means and the first and second reading means. Comparison control means for determining
Disclosed is a damper control device for an axial blower, which is provided with: and an axial blower provided with the control device.

[0009]

Embodiments of the present invention will be described below. FIG. 2 shows an example of the axial blower according to the present invention, in which two blowers 1, 2 whose axes are arranged in parallel with the axial direction of the casing 5 are housed in a casing 5, and a motor is provided. 13 and 14, respectively. On the upstream side of the blowers 1 and 2, suction-side dampers 11 and 12 are provided.
Discharge-side dampers 3, 4 are arranged downstream of the blowers 1, 2, respectively. The suction side dampers 11 and 12 are
The discharge dampers 3 and 4 are opened and closed by motors 16 and 17, respectively. The air generated by the blowers 1 and 2 passes through the discharge-side dampers 3 and 4, and the two flows merge in the flow path 15.

The arithmetic unit 6 can input / output and calculate information by programming. The rotation speed of the motors 13 and 14 of the blower is controlled by sending a signal from the calculator 6 to a motor power supply 7 of the blower. The opening and closing of the damper for controlling the air volume is also controlled by sending a signal from the calculator 6 to the motor power supply 8 of the discharge-side damper. The pressure converter 9 detects the static pressure at the operating point of the system including the two blowers and the flow path 15, and sends the detection signal to the arithmetic unit 6. The storage device 10 stores a function table for control obtained in advance, so that the arithmetic unit 6 can extract a necessary amount.

FIG. 3 shows the input / output status of signals of a control system including the arithmetic unit 6, the storage device 10 and the like of the above-mentioned axial blower. The storage device 10 includes two blowers and a flow path. The rotation speed N (Pd) of one blower, which is a function of the operating point static pressure Pd in one-unit operation in the system including the above, is a function of the respective rotation speeds N1 and N2 when air is blown from two blowers. The static pressure Pa (N1, N2) at a certain operating point and the static pressure Pb (N) at the valley of the characteristic curve, which is a function of the rotation speed N of one blower, are obtained in advance by actual measurement and stored in a table format. Shall be

Next, in the above configuration, the blowers 1, 2
A description will be given below of a method of controlling the timing of releasing the discharge-side damper when starting the operation of one other unit from the operation of only one unit, assuming that the variable speed blowers have the same performance. FIG. 1 is a flowchart showing the control method.
It is assumed that only the blower 1 is operating at a certain rotation speed N1. At this time, the discharge side damper 3 is opened and the discharge side damper 4 is opened.
Is closed (step S0). In this state, the operation of another blower 2 is started (step S1). Then, in order to operate the blower 2 by finally increasing the rotation speed to the same speed as the blower 1, the computing unit 6 supplies the blower 2 to the blower motor power supply 7.
Is given (step S2). At this time, the discharge side damper 4 remains closed.
Next, the static pressure Pd1r in the flow path 15 where the flows from the two blowers join are detected by the pressure converter 9 (Step S).
3). Since this static pressure Pd1r represents the static pressure at the operating point of the system including the two blowers and the flow path during the operation of one fan, the computing unit 6 next determines the rotational speed N1r of the blower 1 with respect to the detected static pressure Pd1r. From the function N (Pd) stored in the storage device 10 (step S4). Note that the rotation speed N obtained here is
1r does not always match the rotation speed N1 indicated by the command signal for rotating the motor 13, but the command value N1
May be extracted in step S4. Alternatively, the actual rotation speed of the motor 13 can be detected. Next, using the rotation speed N2 (command value) of the blower 2 and the value of the rotation speed N1r of the blower 1 obtained in step S4, the computing unit 6 operates at both rotation speeds, and the operating point static pressure Pa
Is obtained from the function Pa (N1, N2) stored in the storage device 10 (step S5), and the rotation speed N2 of the blower 2 is further determined.
Using the (command value), the computing unit 6 calculates the static pressure Pb2 at the valley of the characteristic curve in the single-unit operation by the function Pb stored in the storage device 10.
(N) (step S6).

The operating point static pressure Pa thus determined is
And the valley static pressure Pb2 are compared (step S7).

If Pa−Pb2 <−δ, δ> 0 is satisfied, the arithmetic unit 6 sends a signal for opening the discharge damper 4 to the motor power supply 8 of the discharge side damper, and the two blowers 1, The second parallel operation state is set (step S8). In this way, instead of performing the damper control with the elapsed time after the start of the blower that was started later as in the conventional method, the damper is controlled by obtaining the operating point static pressure from the operating characteristics of the system. Accurate control becomes possible. Therefore, it is not necessary to provide a design having a margin for preventing the occurrence of surging even when the vehicle is operated at any speed as in the related art, and the facility can be realized economically. It should be noted that δ> 0 in (Equation 2) is a constant determined to give a certain margin, since even if the condition of (Equation 1) is satisfied, it is likely to be unstable if the static pressures Pa and Pb2 are substantially equal. is there. On the other hand, when the condition of (Expression 2) is not satisfied, the rotational speed N2 of the blower 2 is still insufficient, so the process returns to Step S5 and repeats until (Expression 2) is satisfied. When the discharge side damper 4 is released, the rotation speed N2 of the blower 2 is changed until the rotation speed N2 of the blower 2 becomes equal to N1.
And the damper control ends (steps S9 to S11).

In the above description, the number of the blowers is two, but it is obvious that the number of the blowers may be three or more.

[0015]

According to the present invention, when a plurality of variable-speed axial-flow blowers arranged in parallel are operated, the discharge-side damper release timing can be accurately controlled when the stopped blower is started. And the occurrence of surging can be reliably prevented. For this reason, it is not necessary to take the operating point static pressure low enough at the time of design, and there is an effect that the equipment cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a flowchart showing an example of a damper control method according to the present invention.

FIG. 2 is a sectional view showing an example of an axial blower according to the present invention and a diagram showing a control system thereof.

FIG. 3 is a diagram showing input / output states of signals in a control system.

FIG. 4 is a diagram showing a relationship between a difference between a suction-side static pressure and a discharge-side static pressure (hereinafter, simply referred to as a “static pressure”) and a flow path resistance with respect to an air volume of a blower.

FIG. 5 is a diagram illustrating an example of tunnel ventilation equipment using a blower.

[Explanation of symbols]

 1, 2 blower 3, 4 discharge side damper 5 casing 6 arithmetic unit 7 blower motor power supply 8 discharge side damper motor power supply 9 pressure converter 10 storage device 11, 12, suction side damper 13, 14, blower motor 15 flow path 16, 17, 18, 19 Motor 51 Tunnel 52 Vehicle 53 Axial blower

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F04D 27/00 F04B 49/00-49/24

Claims (5)

(57) [Claims] 1. A method for controlling a damper of an axial blower provided with two axial blowers, wherein each of the axial blowers is operated when both discharge side dampers of the two axial blowers are opened. The operating point static pressure at the junction of the discharge-side damper outlet, which is determined according to the number of rotations, and the junction, determined according to the number of rotations when only one axial blower is operated, The valley static pressure at the valley of the change characteristic of the static pressure with respect to the air flow in the valley is measured in advance for each rotation speed and stored in the storage means, and the first shaft of the two axial flow blowers is used. When the blower is operated at the first speed and the second axial blower is stopped and the discharge side damper is closed, and the operation is started by increasing the rotation speed of the second axial blower. Then, from the rotation speed of the first and second axial blowers, The operating point static pressure and the valley static pressure are read from the storage means from the rotation speed of the second axial blower, and the read operating point static pressure and the valley static pressure are compared by reading the valley static pressure. 2. A damper control method for an axial blower, wherein a timing for opening a discharge side damper of the axial blower is determined. 2. The damper control method according to claim 1, wherein when the read operating point static pressure is smaller than a value obtained by subtracting a predetermined margin value from the read valley static pressure, A damper control method for an axial blower, wherein the timing is such that a discharge-side damper of a second axial blower is opened. 3. A damper control device for an axial blower provided with two axial blowers, wherein each of the axial blowers is operated when both discharge side dampers of the two axial blowers are opened. The first storage means for previously measuring and storing the operating point static pressure at the junction of the discharge-side damper outlet, which is determined according to the number of rotations, and operating only one axial blower Second storage means for previously measuring and storing a valley static pressure at a valley of a change characteristic of a static pressure with respect to an air flow at the confluence, which is determined according to a rotation speed at the time; The first axial blower of the axial blowers is operated at the first speed, the second axial blower is stopped, and the discharge side damper is closed. At the start of parallel operation in which operation is started by increasing the First reading means for reading the operating point static pressure at that time from the first storage means from the rotation speeds of the first and second axial blowers; and Second reading means for reading the valley static pressure from the second storage means from the rotation speed; and the operating point static pressure and the valley static pressure read by the first and second reading means. And a comparison control means for determining a timing for opening the discharge-side damper of the second axial blower by comparing the damper control apparatus and the second axial blower. 4. The damper control device for an axial blower according to claim 3, wherein the comparison control means calculates the operating point static pressure from a value obtained by subtracting a predetermined margin value from the valley static pressure. A damper control device for an axial flow blower, wherein a time when the pressure is also reduced is a timing at which the discharge side damper of the second axial flow blower is opened. 5. An axial blower, comprising the damper control device for an axial blower according to claim 4 in a control system thereof.