JPH0332704B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) This invention relates to an air conditioner, and in particular, the required air volume is adjusted at a duct terminal using, for example, a VAV (variable air volume) unit, and the blower is rotated according to the required air volume. Related to air conditioners that control the number of air conditioners.

(Prior art) In blowers used in air conditioners,
It is generally known that "surging" occurs. Surging in a blower is when the air volume it handles drops below a certain limit, and air in the normal flow direction does not fill the flow path between the impeller blades, leading to a stall state or a backflow of air. This means that the airflow pulsates, resulting in unstable operation. If such surging occurs in the blower, noise and vibration will increase, and in extreme cases, it may cause damage to the impeller bearing or the impeller or blades themselves.

(Problems to be Solved by the Invention) Conventionally, air conditioners using a VAV unit, such as those disclosed in, for example, co-pending Japanese Patent Application Laid-Open No. 61-41842 filed by the present applicant, have been proposed. In the past, there was no effective device for preventing the surging of the blower as described above.

Therefore, the main object of the present invention is to provide a novel air conditioner that can effectively prevent surging of the blower.

(Means for Solving the Problems) Simply put, the present invention includes a blower having a suction port and a discharge port, a main duct connected to the discharge port of the blower, and a plurality of ducts branching from the main duct. An air conditioner comprising a branch duct and an air volume adjustment means provided in each of the plurality of branch ducts to adjust the air volume of the branch duct, and in which the rotation speed of a blower is controlled according to the state of the air volume adjustment means. , a bypass duct branched from the main duct and connected to the suction port of the blower, a bypass air volume adjustment means provided in the bypass duct to adjust the air volume of the bypass duct, and whether or not the blower is in a surging region. This is an air conditioner comprising a means for detecting the air flow rate, and a control means for controlling the bypass air volume adjusting means in accordance with the detection by the detection means.

(Function) Based on a signal from a wind speed sensor provided in the main duct, a signal representing the rotation speed of the blower, etc., the detection means detects whether the blower is in the surging region at the rotation speed. When it is detected that the surging region is present, the detection signal is given to the control means. The control means controls the bypass air volume adjustment means. In response, airflow from the blower flows through the bypass duct, the amount of air blown increases, and the blower escapes from the surging region.

(Effects of the Invention) According to the present invention, surging of the blower can be effectively prevented with a simple configuration.

The above objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

(Embodiment) FIG. 1 is a block diagram showing an embodiment of the present invention. For example, a blower 10 such as a Sirotskov fan is formed with a suction port 10a and a discharge port 10b. Blower 10 includes an impeller (not shown) driven by blower motor 12 . The blower motor 12 drives its impeller, the rotational speed of which is controlled by rotation control means, such as an inverter 14.

A main duct 16 is provided at the outlet 10b of the blower 10.
is connected to the main duct 16, and a plurality of branch ducts 18, 18, . . . are connected to the terminals of the main duct 16. Each branch duct 18, 18,... has a damper (not shown) as an air volume adjustment means.
Units 20, 20, . . . are provided.

The frequency of the inverter 14 mentioned above is controlled based on the opening degree of the VAV unit 20 provided in the branch duct 18. In other words, the amount of air blown from the blower 10 to the main duct 16 is
It is controlled according to the opening degree of 0, 20, . This is disclosed in detail in Japanese Patent Application Laid-Open No. 61-41842 cited above, etc. Therefore, here, we will discuss the air volume adjustment itself of the blower 10 according to the opening degree of the VAV unit 20. Explanation will be omitted.

The main duct 16 is provided with a wind speed sensor 22 for detecting the amount of air flowing through the main duct 16. This wind speed sensor 22 is also manufactured by JP-A-Sho.
A wind speed sensor using a Karman vortex as disclosed in Japanese Patent No. 61-41842 may be used.

A bypass duct 24 is connected between the main duct 16 and the suction port 10a of the blower 10. This bypass duct 24 is for forming another air flow path from the main duct 16 to the blower 10 so that the air volume of the blower does not fall below a certain level when surging occurs in the blower 10. and,
This bypass duct 24 has a VAV unit 2
Bypass air volume adjusting means such as 6 is provided.
The VAV unit 26 is provided with a damper drive circuit 27 for controlling the opening degree of the damper included therein.

The system further includes a surging prevention circuit 2.
8 is provided. This surging prevention circuit 28 is supplied with a frequency signal from the above-mentioned inverter 14 as well as a signal from the wind speed sensor 22. Simply put, the surging prevention circuit 28 detects the air volume that falls within the surging range at the current rotational speed of the blower 10 based on the frequency of the inverter 14 (in this specification, simply referred to as "surging air volume").
) and the amount of air blown from the blower 10 (actual air amount), it is determined whether the blower 10 is in the surging region, and if it is in the surging region, the VAV unit 26 of the bypass duct 24 is Controls the damper to open.

Referring to FIG. 3, the horizontal axis shows the air volume, and the vertical axis shows the static pressure of the blower. Blower 10
The area to the left of the surging line determined by the type of is the surging area, and the area to the right is an area where no surging occurs. In FIG. 3, the air volume on the surge line at the maximum rotational speed N ₀ of the blower 10 is shown as the maximum air volume Q ₀ . The blower 10 is
Normally, VAV units 20, 20,... (Fig. 1)
It is driven at a certain rotational speed N determined according to the opening degree of. The surging air volume at this rotation speed N is "Q'", and the actual air volume at the rotation speed N (which can be determined by the wind speed sensor 22) is "Q". Incidentally, point X in Fig. 3 is the blower 10.
is in the surging region, that is, Q'>Q.

Note that the actual air volume Q ₁ of the main duct 16 downstream of the bypass duct 24 is the air volume required for the system,
The actual air volume Q ₂ of the bypass duct 24 is ultimately controlled by Q=Q ₁ +Q ₂ .

To explain the surging prevention circuit 28 in detail with reference to FIG. 2, the surging prevention circuit 28
includes an inverter frequency receiving circuit 30 for receiving the frequency signal from the inverter 14. This inverter frequency receiving circuit 30 provides, for example, an AC signal according to the frequency of the inverter at that time to the fan rotation speed calculation circuit 32. The fan rotation speed calculation circuit 32 supplies data or signals corresponding to the fan rotation speed N at that time to the surging air volume, ie, Q' calculation circuit 34.

The Q calculation circuit 34 includes constant circuits 36 and 38.
, respectively, the maximum surging air volume Q ₀ mentioned above
Data or signal corresponding to and maximum rotation speed
Data or signals corresponding to N ₀ are given.
In the Q' calculation circuit 34, since Q ₀ /N ₀ =Q'/N holds true on the surge line,
Q′=(Q ₀ /N ₀ )×N, surging air volume
Find Q′.

Data or signals corresponding to the surging air volume Q' from the Q' calculation circuit 34 are given to the division circuit 40.

On the other hand, the signal from the wind speed sensor 22 is given to the wind speed sensor receiving circuit 42, and the wind speed sensor receiving circuit 42 outputs a voltage signal according to the wind speed. This signal is then given to the air volume calculation circuit 44. The wind speed and the air volume determined by the wind speed sensor 22 have a certain relationship, so the air volume calculation circuit 44 outputs data or a signal representing the actual air volume Q in accordance with this relationship. This actual air volume Q
The data or signal representing
is given as the other input.

The division circuit 40 performs division (=Q/Q') to determine which of the actual air volume Q and the air volume Q' on the surge line is larger. The results are provided to comparison circuits 46 and 48, respectively.

The comparison circuit 46 determines whether Q/Q' calculated by the division circuit 40 is less than "1", that is, whether Q'>Q.
The comparison circuit 48 determines whether Q/Q' is greater than "1.1", that is, Q/Q'≧1.1.

When the signal is output from the comparator circuit 46, Q'>Q (Q/Q'<1), and therefore the blower 10 is in the surging region, so a signal is given to the bypass damper open command circuit 50. It will be done. Accordingly, from this bypass damper open command circuit 50,
A signal for controlling a damper (not shown) included in the VAV unit 26 in the opening direction is output to the damper drive circuit 27. If a signal is obtained from the comparison circuit 48, the bypass damper closing command circuit 5
A signal is given to the bypass damper closing command circuit 52 to the damper drive circuit 27.
A signal is provided to control the damper included in unit 26 in the closing direction.

In this embodiment, the comparator circuit 46 has Q/
Q′<1 is detected, and the comparator circuit 48 detects Q/Q′≧1.1.
We are trying to detect this. Therefore, the two comparison circuits 46 and 48 calculate “0.1 (=1.1−
1)" dead zone is set. This dead zone is created by frequently opening and closing the damper of the VAV unit 26 of the bypass duct 24.
This is provided to prevent minute load fluctuations as much as possible. Therefore, in this dead zone, no signal is obtained from either of the command circuits 50 and 52, and therefore, the opening degree of the damper of the VAV unit 26 at that time is maintained as it is.

In operation, when the blower 10 is not in the surging region, the division result "Q/Q'" in the division circuit 40 is greater than "1.1"(Q/Q'≧1),
Therefore, a signal is output from the comparison circuit 48.
For this purpose, a signal is given from the bypass damper close command circuit 52 to the damper drive circuit 27, and therefore the damper of the VAV unit 26 included in the bypass duct 24 is closed. That is, the eighth
In the normal operating state shown in Figure A, the actual air volume Q is larger than the surging air volume Q', as shown at point A in Figure 8, and therefore, at this time, the damper of the VAV unit 26 of the bypass duct 24 is closed. It remains as it is.

For example, assume that part or all of the VAV unit 20 included in the branch duct 18 in FIG. 1 is closed. Then, the required air volume _Q1 necessary for the system becomes smaller, and the inverter 14 is controlled according to the required air volume _Q1 ,
Although the amount of air blown from the blower 10 is reduced, this control requires a relatively long time, for example, 10 to 15 minutes. If the loop is designed to respond too quickly, control hunting will occur, so it is common to set the response speed to a certain level.

However, the fully closed state of the VAV unit 20 is achieved within a relatively short period of time, for example, within two minutes, and if no control is performed during that time, surging will occur as described above. However, in this embodiment, since the bypass duct 24 is provided, such surging can be effectively prevented.

In other words, when a large number of terminal VAV units 20 receive a full-close command at the same time or when a sudden load change occurs, the terminal VAV units 20
It is assumed that the valve enters a rapid throttling operation (closing operation),
Assume that the final target air volume in this state is point C in FIG. 8A. In such a state, the inverter 14
Since the response of the fan is slow, the rotational speed N of the fan and the surging air volume Q' become too large.
As shown by point B in the figure, the blower 10 enters the surging region.

Specifically, when all or part of the VAV unit 20 suddenly becomes fully closed, the required air volume _Q1 of the entire system becomes smaller, and therefore the actual air volume Q of the main duct 16 from the blower 10 also becomes smaller. . On the other hand, the frequency of the inverter 14 is not yet completely controlled, so the blower 10 is
The VAV unit 20 is operated at the rotational speed before the fully closed state occurs. Therefore, the surging air volume Q' at that rotation speed N becomes larger than the actual air volume Q.

In such a state, the division result "Q/Q'" in the division circuit 40 becomes smaller than "1", and therefore a signal is output from the comparison circuit 46,
It is given to the bypass damper open command circuit 50. From this bypass damper open command circuit 50,
A signal is applied to the damper drive circuit 27, and the damper of the VAV unit 26 included in the bypass duct 24 is controlled in the opening direction. That is, when a signal from the bypass damper open command circuit 50 is given,
The damper included in the VAV unit 26 is opened by a certain opening degree.

If the damper opening degree of the VAV unit 26 is insufficient, a signal is still output from the comparator circuit 46, and the damper of the VAV unit 26 is further opened by a certain opening degree. Then, by repeating such control of the VAV unit 26, eventually
Q=Q', and the result "Q/Q'" in the division circuit 40 becomes "1" or more. Then, the comparator circuit 46 and therefore the bypass damper opening command circuit 50 no longer output a signal, and the VAV unit 26 of the bypass duct 24 maintains the opening state at that time.

That is, in the surging region of the blower 10, the VAV unit 26 of the bypass duct 24 is controlled by the signal from the bypass damper open command circuit 50 until Q/Q'=1 (Q=Q'). The damper continues to be driven in the opening direction. After that, Q=
Q', that is, the rotational speed N of the blower 10 decreases and the surging air volume Q' decreases,
When the actual air volume Q becomes equal to the previously reduced actual air volume Q, that is, when the point B moves to the point D as shown in FIG. 8B, the opening operation of the bypass damper is stopped.

Depending on the status of the VAV units 20, 20, ... of the terminal, the inverter 14 is gradually controlled by a control circuit (not shown), and eventually the rotational speed N of the blower 10 decreases, so that Q'=(Q ₀ / The surging air volume Q' given by N ₀ )×N becomes smaller. Then, the division result in the division circuit 40 is "Q/Q'"
exceeds "1.1", and the comparison circuit 48 outputs a signal. Accordingly, a signal is given from the bypass damper closing command circuit 52 to the damper drive circuit 27, and the VAV included in the bypass duct 24 is
The damper of unit 26 is closed by a certain opening.

In other words, by controlling the inverter 14,
When the rotation speed of the blower 10 further decreases, the target resistance curve is low as shown in Figure 8C, so the actual air volume Q becomes larger than the surging air volume Q', and as shown in Figure 8C, the previous point D moves to point E. The rotational speed of the blower 10 is further reduced, and the actual air volume Q shifts from point E as shown in FIG. 8D.
Eventually, the initially set target air volume, ie, point C shown in FIG. 8A, is reached. Then, the fan 10 enters a normal operating state with a reduced rotational speed, and the blower 10 exits the surging region.

When the blower 10 escapes from the surging area,
The damper of the VAV unit 26 is in the fully closed state, as described above. That is, if Q/Q'≧1.1 at point E in Figure 8C, then Q/Q'=
1.1, the bypass damper close command circuit 52
A signal is output from the VAV unit 26 and the damper of the VAV unit 26 included in the bypass duct 24 is closed.

From the above explanation, in the dead zone, no output is obtained from either of the comparison circuits 46 and 48;
It will be appreciated that the bypass damper (VAV unit 26) remains in its current state.

FIG. 4 is a circuit diagram showing a preferred circuit example of the embodiment of FIG. 2. Although not shown, the fan rotation speed calculation circuit 32 integrates the frequency signal from the inverter frequency reception circuit 30, for example, and calculates the magnitude of the voltage signal at the maximum rotation speed _N0 , as shown in FIG. For example, if it is 10V, a voltage corresponding to the fan rotation speed at that time, which is usually 10V or less, is output. A voltage representing this rotational speed N is applied to the Q' calculation circuit 34.

The operational circuit 34 includes an operational amplifier 34a, and a voltage signal corresponding to the rotation speed N is applied to the (-) terminal of the operational amplifier 34a. A predetermined voltage determined by resistors 34b and 34c is applied to the (+) terminal of operational amplifier 34a. Further, a feedback resistor 34d is connected between the (-) terminal and the output terminal of the operational amplifier 34a. Therefore, this operational amplifier 34a is configured as an inverting amplifier as a whole. The above-mentioned resistors 34b to 34d are the first
Acts as constant circuits 36 and 38 in the figure. Therefore, the output of the Q' calculation circuit 34, that is, the output of the operational amplifier 34a, is, for example, a voltage of 10V to 0V, which is the inversion of the voltage signal from the fan rotation speed calculation circuit 32, as shown in FIG. is output as a signal representing the surging air volume Q'.

On the other hand, a voltage signal from 0V to 10V corresponding to the wind speed in the main duct 16 is given from the wind speed sensor receiving circuit 42 . This voltage signal is transmitted to the air volume calculation circuit 44.
The converter 44a included in the actual air volume Q
It is output as a voltage signal representing . That is, in the air volume calculation circuit 44, the voltage signal from the wind speed sensor receiving circuit 42 is converted by the converter 44a into
For example, the voltage of the actual air volume Q with a predetermined proportional relationship
Converted to a 0V to 10V signal.

Then, the voltage signal V _Q ′ corresponding to the surging air volume Q′ from the Q′ calculation circuit 32 and the air volume calculation circuit 4
A voltage signal corresponding to the actual air volume Q from 4 is applied to each of the resistors 40a and 40b forming the divider circuit 40. The divider circuit 40 is configured as an averaging circuit in this embodiment, and performs the calculation (V _Q +V _Q ′)/2=V _Q/Q ′ based on the voltage signals V _Q and V _Q .

The voltage V _Q/Q from the divider circuit 40 is applied to the comparator circuit 46.
and the (+) terminal of an operational amplifier 48a included in the comparator circuit 48, respectively. operational amplifier 4
Resistors 46b and 46c are connected to the (+) terminal of 6a.
A constant voltage, for example 5V, determined by is applied. Similarly, a constant voltage, for example 5.5V, determined by resistors 48b and 48c is applied to the (-) terminal of operational amplifier 48a. That is,
The operational amplifier 46a of the comparator circuit 46 receives the input voltage
Determine whether V _Q/Q ′ is less than 5V. Conversely, operational amplifier 48a of comparison circuit 48 determines whether the applied voltage V _Q/Q ' is greater than 5.5V.

The output from the comparison circuit 46 is applied to a bypass damper open command circuit, ie, a relay 50, and the output of the comparison circuit 48 is applied to a bypass damper close command circuit, ie, a relay 52.

The contact 50a of the relay 50 is connected to the damper drive circuit 2.
7 (FIG. 1) is inserted into the drive circuit of the damper opening motor 27a. Similarly, relay 52
The contact 52a is inserted into the drive circuit of the damper closing motor 27b of the damper drive circuit 27. Therefore, when the relay 50 is turned on, its contacts 50
a is turned on, the damper opening motor 27a is driven, and the damper of the VAV unit 26 included in the bypass duct 24 is driven in the opening direction. If the relay 52 is turned on, the contact 52a is turned on,
The damper closing motor 27b is driven and its VAV
The damper of unit 26 is driven in the closing direction.

FIG. 9 is a block diagram showing another embodiment of the invention. In this embodiment, the bypass duct 24
A wind speed sensor 54 is provided in the main duct 16 on the downstream side, and a wind speed sensor 56 is also provided in the bypass duct 24.
will be provided. The signals from these two wind speed sensors 54 and 56 are then transmitted to the surging prevention circuit 2 along with the frequency signal from the inverter 14.
8'.

The surging prevention circuit 28' of this embodiment includes:
As shown in FIG. 10, a wind speed sensor receiving circuit 58 that receives a signal from the wind speed sensor 54 and a wind speed sensor receiving circuit 60 that receives a signal from the wind speed sensor 56 are provided. The data or signal from the wind speed sensor receiving circuit 58 is then given to an air volume calculation circuit 62 as shown in FIG. 4, for example.
Data or signals from the wind speed sensor receiving circuit 60 are given to the air volume calculation circuit 64. Since the wind speed sensor 54 is installed in the main duct 16, the output of the air volume calculation circuit 62 is based on the actual air volume required for the system.
Corresponds to Q ₁ . Furthermore, since the wind speed sensor 56 is provided in the bypass duct 24, the output from the air volume calculation circuit 64 corresponds to the actual air volume Q2 passing through the bypass duct ₂₄ . This embodiment utilizes the actual air volume Q ₂ of the bypass duct 24.

In FIG. 10, similar to the previous embodiment,
The signal from the Q' arithmetic circuit 34 is sent to the _Q2 ' arithmetic circuit 66.
given to. This Q ₂ ' calculation circuit 66 calculates the air volume Q ₁ required for the system and the surging air volume at that time.
Q ₂ ′ (=Q′−Q ₁ ) is calculated based on Q′.

Then, the data or signal from this Q ₂ ' calculation circuit 66 is given to the division circuit 40', and the calculation of Q ₂ /Q ₂ ' is performed in this division circuit 40'.
The results are provided to two comparison circuits 46' and 48', respectively. In the comparison circuits 46' and 48', the result "Q ₂ /Q ₂ '" of the division circuit 40' is "1".
Compare whether it is smaller than or larger than “1.1”. These comparison circuits 46'
and 48' outputs are as in the previous example,
They are given to a bypass damper open command circuit 50 and a bypass damper close command circuit 52, respectively.

In this way, in the embodiment shown in FIGS. 9 and 10, the air flow rate or actual air flow Q from the main duct 16 on the upstream side from where the bypass duct 24 is branched is determined, and the actual air flow is Q to Q=
While the actual air volume Q ₂ of the bypass duct 24 was determined according to the formula Q ₁ + Q ₂ ,
The actual air volume Q 1 in the main duct 16 on the downstream side from which the bypass duct ₂₄ branches and the actual air volume Q ₂ in the bypass duct 24 can be determined individually by the individual wind speed sensors 54 and 56, respectively.

According to the embodiments of FIGS. 9 and 10 described above,
Since the actual air volume Q ₂ flowing through the bypass duct 24 is detected, the control accuracy can be further improved compared to the previous embodiments shown in FIGS. 1 and 2.

It should be noted that all of the above embodiments were constructed using discrete circuits, as shown in FIG. 4, for example. However, in order to implement the present invention, it may be controlled by a microcomputer or a program for it.
Of course.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention. FIG. 2 is a block diagram showing an example of the surging prevention circuit in the embodiment of FIG. 1. Third
The figure is a graph for explaining the surging region of the blower, with the horizontal axis showing the air volume and the vertical axis showing the static pressure of the blower. FIG. 4 is a circuit diagram showing a specific example of the circuit of the embodiment shown in FIG. FIG. 5 is a graph for explaining the operation of the fan rotation speed calculation circuit. FIG. 6 is a graph for explaining the operation of the Q' calculation circuit. FIG. 7 is a graph for explaining the operation of the air volume calculation circuit. Figure 8A-8
Figure D is a graph for explaining the surging prevention operation. FIG. 9 is a block diagram showing another embodiment of the invention. FIG. 10 is a block diagram showing an example of the surging prevention circuit of the embodiment shown in FIG. In the figure, 10 is a blower, 14 is an inverter, 16 is a main duct, 18 is a branch duct, 20 is a terminal VAV unit, 22, 54, 56 are wind speed sensors, 24 is a bypass duct, and 26 is for bypass.
VAV unit 28, 28' indicates a surging prevention circuit.

Claims (1)

[Scope of Claims] 1. A blower having a suction port and a discharge port, a main duct connected to the discharge port of the blower, a plurality of branch ducts branching from the main duct, and a blower provided in each of the plurality of branch ducts. and an air volume adjustment means for adjusting the air volume of the branch duct, and the rotation speed of the blower is controlled according to the state of the air volume adjustment means. a bypass duct connected to the suction port; a bypass air volume adjustment means provided in the bypass duct to adjust the air volume of the bypass duct; a rotational speed N, a maximum rotational speed _N0 , and a maximum rotational speed of the blower; Based on the surging air volume _Q0 when , the surging air volume Q' at the rotation speed N is
A means for calculating Q′=(Q ₀ /N ₀ )×N, a wind speed sensor provided in the main duct upstream from where the bypass duct branches, and a means for converting the wind speed from the wind speed sensor into an air volume. a detection means for detecting whether or not the blower is in a surging region, the detection means comprising means for determining an actual air volume Q, and means for comparing the surging air volume Q' and the actual air volume Q based on the surging air volume Q; An air conditioner comprising: a control means for controlling the bypass air volume adjusting means in accordance with detection by the detection means. 2. A blower having a suction port and a discharge port, a main duct connected to the discharge port of the blower, a plurality of branch ducts branching from the main duct, and a plurality of branch ducts provided in each of the plurality of branch ducts and connected to the discharge port of the blower. In an air conditioner comprising an air volume adjusting means for adjusting air volume, and in which the rotation speed of the blower is controlled according to the state of the air volume adjusting means, the air conditioner is branched from the main duct and connected to the suction port of the blower. a bypass duct provided in the bypass duct, a bypass air volume adjusting means provided in the bypass duct to adjust the air volume of the bypass duct, a rotation speed N and a maximum rotation speed N ₀ of the blower, and a surging air volume Q ₀ at the maximum rotation speed. Based on, the surging air volume Q' at the rotation speed N is
means for calculating Q′=(Q ₀ /N ₀ )×N; a first wind speed sensor provided in the main duct downstream from where the bypass duct branches; and a second wind speed sensor provided in the bypass duct. calculation for calculating _Q2 '(=Q'- _Q1 ) based on the wind speed sensor, the surging air volume Q' of the blower, and the actual air volume _Q1 of the main duct based on the first wind speed sensor. and means for comparing the actual air volume Q ₂ of the bypass duct based on the second wind speed sensor with the Q ₂ ′, for detecting whether the blower is in a surging region. , and an air conditioner comprising: a control means for controlling the bypass air volume adjusting means in accordance with detection by the detection means.