JPH02146412A - Control device for blower - Google Patents

Abstract

PURPOSE:To prevent the deterioration of combustion performance of combustion equipment by detecting any fluctuation in the characteristics of a foreign matter on an air supply side or the adhesion of a foreign matter on an impeller based on the application of a current detector designed to detect a drive current of said blower. CONSTITUTION:A rotary speed control means 7 is adapted to feed back a rotary speed signal of a rotary speed detector 8 in order to supply combustion air equivalent to the combustion rate of a burner 2 present by a combustion control means 6. A current detector 9 detects a drive current iP of a motor 1b which comprises a blower 1. Combustion equipment controls a rotary speed N within the range between the maximum combustion quantity Qgm and the minimum combustion quantity Qgo. The drive current iP generally indicates a load characteristic value. For example, the motor drive current iP in the case of a certain combustion quantity Qga is iPo while the rotary speed N is No. However, when the blower 1 is subjected to the generation of air supply clogging or the adhesion of a foreign matter on an impeller, its performance moves to an abnormal load characteristic and the current value iP drops to iPa, but the rotary speed N maintains No by rotary speed control. Therefore, the operating state of the blower 1 is monitored by detecting the current of the blower motor. When the current iP reaches 1Pa or more specifically the abnormal load characteristic is, this invention will give a warning to indicate a failure of the ventilation system.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to blower control for combustion equipment, etc., in which air for combustion is supplied by a blower.

2. Description of the Related Art As shown in FIG. 4, a conventional blower control device of this type is comprised of a blower l that supplies combustion air, a proportional control valve 3 that adjusts the combustion amount of the burner 2, and the like. As shown in the figure, the number of revolutions of the air blower ml was controlled between the maximum combustion amount and the minimum combustion amount of the burner 2 according to the burner combustion amount.

Problem to be Solved by the Invention However, with the above configuration, the wind I shown in FIG.
From the air blowing characteristics of Q, pressure P, and rotation speed N, the normal load point O shown by the solid line moves to point A on the abnormal load line shown by the broken line due to air supply blockage of the blower, and the air volume changes from Qo to Qa.
Although the rotation speed N decreases from No to Na
increases to

Therefore, in the rotation speed control described above, in the blower load characteristic passing through point A on the abnormal load line, control is performed to return the rotation speed from Na to No, and the voltage applied to the blower 1 is lowered. As a result, the blower characteristics shown by the broken line are obtained, and the rotation speed N
When No' is equal to o, the air volume decreases further than Qa and Q
o'.

Therefore, as a combustion device, there is a problem in that the amount of air is insufficient and the combustion performance is deteriorated.

The present invention solves such conventional problems and aims to prevent deterioration of combustion performance of combustion equipment.

Means for Solving the Problems In order to solve the above problems, the blower control device of the present invention includes:
a rotation speed detection section that detects the rotation speed of the blower; a blower rotation speed control means that feeds back a signal from the rotation speed detection section; a current detection section that detects the drive current of the blower;
a comparison section that compares a blower drive current value at a set rotation speed by the rotation speed control means with a current value of a set current section determined according to the set rotation speed; and an output of the comparison section that issues an alarm. It is equipped with a configuration called notification means.

Effect of the Invention With the above-described configuration, the present invention detects blower characteristic fluctuations caused by foreign matter clogging in the blower air supply example, foreign matter adhering to the blower impeller, etc. by the current detection unit that detects the blower a drive current, and sets the current value. When the current drops below a set value determined according to the rotation speed, an alarm will be issued.

Embodiments Hereinafter, embodiments of the present invention will be described based on the accompanying drawings in the case of a forced air supply/exhaust type gas instantaneous hot water heater.

In FIG. 1, the same members as in the conventional example are given the same reference numerals. 2 is a blower consisting of an impeller 1a and a drive motor 1b; 2 is a burner whose combustion amount is adjusted by a proportional control valve 3; A heat exchanger 4 is heated by a burner 2, and constitutes a gas instantaneous water heater 5 that converts water supplied to the heat exchanger 4 into hot water to supply hot water.

Reference numeral 6 denotes a combustion control unit that detects the hot water temperature of the heat exchanger 4 (not shown), adjusts the combustion amount with the proportional control valve 3 so that the temperature reaches the set temperature, and controls the operation sequence of the water heater 5.

7 is a rotation speed detection unit 8 of the blower 1 to supply combustion air corresponding to the combustion amount of the burner 2 set by the combustion control unit 6.
The rotation speed control means of the blower is formed by feeding back the rotation speed signal of the blower, and the control law is configured by PID.

Reference numeral 9 denotes a current detection unit that detects the drive current P of the motor lb constituting the blower 1, and 10 a setting current unit that sets the drive current of the blower motor 1b at the set rotation speed controlled by the rotation speed fI1 means 7. Yes, it is set to a value determined in advance through experiments or the like depending on the load condition of the blower 1. 11 is a comparison unit that compares the current value iP of the current detection unit 9 and the set current value iS, and 12 is a notification means controlled by the output of the comparison unit 11, which is activated when the comparison unit 11 becomes iS≧iP. be done.

The notification means may be configured to notify the main body of the water heater 50 or the remote control with a display lamp or a buzzer sound, and any means that can be recognized by the user may be used.

The operation of the blower 1 in the above configuration will be explained using the air blowing characteristics shown in FIG. 2 and the combustion machine air blowing characteristics shown in FIG. 3.

From the airflow characteristics of the air volume Q, pressure P, and current iP shown in Figure 2, the current iPo at the normal load point Ko shown by the solid line is:
Abnormal load point K indicated by a broken line due to air intake clogging of blower 1, etc.
a, and the current P at that time decreases to iPa. In other words, the blowing load on the blower 1 is reduced.

This state can be explained using the combustor air blowing characteristics shown in Fig. 3. If the horizontal axis is the burner combustion amount Qg, and the vertical axis is the blower motor current iP and rotation speed N, then the combustor has the maximum combustion FJ Q g m
The rotation speed N is controlled between the minimum combustion IQgo and the current value iP, which is the value on the normal load characteristics shown by the solid line.For example, when a certain combustion amount Qga, the motor current iP is iPo and the rotation speed N is The answer is No. However, if air supply clogging of the blower 1 or foreign matter adhering to the impeller occurs, the load characteristics shift to the abnormal load characteristics shown in Fig. 2, and the current value iP decreases to iPa, but the rotation speed N is maintained at No by rotation speed control. become.

Therefore, it is possible to monitor the operating state of the blower 1 by detecting the current of the blower motor, and the current iP
When it reaches iPa, that is, the abnormal load characteristic is value, a warning can be issued to notify the abnormality of the air blowing configuration.

It goes without saying that the notification should be made until the worst limit characteristic id is reached based on the combustion characteristics of the combustor.

Effects of the Invention As described above, according to the blower control device of the present invention, the following effects can be obtained.

(1) By utilizing the characteristics of the blower's air blowing characteristics and notifying the deterioration of the air blowing characteristics of the blower in advance, it is possible to prevent equipment system failure.

(2) In combustion equipment, it is possible to prevent deterioration of combustion performance, eliminate wasted energy due to reduced efficiency, and
Since it is possible to avoid the situation where the device suddenly becomes unusable, it is possible to eliminate the inconvenience in daily life.

[Brief explanation of the drawing]

FIG. 1 shows how the blower is controlled in one embodiment of the present invention. 11 block diagram, Fig. 2 is a blower characteristic diagram of the same blower, Fig. 3 is a blower control characteristic diagram of the same combustion equipment, Fig. 4 is a schematic diagram of the conventional combustion equipment, and Fig. 5 is a control characteristic diagram of the same blower. , FIG. 6 is a characteristic diagram of the conventional blower. 1...Blower, 8...Rotation detection unit, 7
... Rotation speed control means, 9 ... Current detection section, 10 ... Setting current section, 11 ... Comparison section, 12 ... Notification means. Name of agent: Patent attorney Shigetaka Awano

Claims (1)

[Claims] A blower consists of a motor and an impeller attached to the motor shaft that blows air, a rotation speed detection section that detects the rotation speed of the blower, and a rotation speed detection section that feeds back a signal from the rotation speed detection section to detect the rotation speed of the blower. A rotation speed control means for controlling the rotation speed to a constant value, a current detection section for detecting a drive current of the blower motor, and a drive current value and a set rotation speed at a set rotation speed controlled by the rotation speed control means. What is claimed is: 1. A control device for a blower, comprising: a comparison section that compares a current value of a set current section determined accordingly; and a notification means that issues an alarm based on the output of the comparison section.