JPS5874120A - Clogging detector for air cleaner - Google Patents

Abstract

PURPOSE:To assure stable operation of a clogging detector for a long period of time without failure in conduction owing to corrosion by using a light emitting diode and a phototransistor to said detector. CONSTITUTION:Upon starting of an engine, a switch 25 of a circuit 20 is turned on and electric current flows to a light emitting diode 14 of the backing 11 for a luminous body 3, then said luminous body emits light. The ray by the light emission is shielded by a shielding body 4 and is prevented from arriving at a phototransistor 15. According to the clogging of a filter element, the inside of the negative pressure chamber 8 of a clogging detector 10 is evacuated and a bellows 2 is moved downward. When the negative pressure in the chamber 8 attains a set value, the top end of the plate 4 moves downward below the optical path connecting the diode 14 and the phototransistor 15. Then the ray arrives at the phototransistor 15 and electric current flows to a light emitting diode 22 for warning, thus allowing the diode to emit light and alarming that the detector is held clogged.

Description

DETAILED DESCRIPTION OF THE INVENTION The present application relates to a spot detection device for an air cleaner of an internal combustion engine.

The clogging detection device has a function of detecting the state of clogging of a filter element in an air cleaner and warning that it is time to replace the filter element. Conventionally used devices of this type correspond to the clogged state of the filter element with the negative pressure on the clean side of the filter element, and an actuating body such as a diaphragm connects the switching contact at a predetermined negative pressure value. It has a structure in which it is brought into contact with a terminal, conducts an electric circuit, and emits a warning lamp i. However, in devices such as 1, in which electrical circuits are made conductive by mechanical switching contacts, there is a risk that foreign matter may adhere to the switching contacts or corrosion may occur, resulting in poor continuity.

Therefore, in view of the above-mentioned book, this book (■) detects clogging in a detection device that conducts an electric circuit at a predetermined clogging state, that is, at a set negative pressure value to alert the clogging state. A detection device is provided.

To explain by way of an embodiment, FIG. 1 shows a clogging detection device 10''e of the present invention, which also includes a casing 1, a bellows 21, a light emitter 3, a shield 4, and a spring 5.The casing 1 has an atmosphere communication opening. 6 and a negative pressure inlet port, and the inside is connected by a bellows 2 to a negative pressure chamber 8, an atmosphere communication chamber 9, and a lζ
compartmentalized. Also, on the wall inside the casing, there are 3 light emitters.
The 6 light emitters 3 for which the
It has two supporting bodies 11 and 13 spaced apart from each other, and a light emitting diode 14 and a phototransistor 15 are disposed facing each other on each of these opposing surfaces 11m and 13m. An optical path is formed between the light emitting diode 14 and the phototransistor 15 as shown by the broken line. 16.17.1
8.19 are connection plugs, each of which has a light emitting diode 14.
, phototransistor 151, etc. are withdrawn.

The shielding body 4 has a thin plate shape, its lower end is in contact with the bellows 2, and it is inserted into the space between the supports 11 and 13 of the light emitter 3. This divides the space into two, with light emitting diode 1
The optical path connecting 4 and phototransistor 15 is cut off. A spring 5 is provided between the upper end of the shield 4 and the inner upper wall of the casing 1. The negative pressure inlet port of the casing 1 is connected to the clean side (not shown) of the filter element.

The connection plugs 16, 17, 18, 19 of the light emitter 3 are connected to a power supply and a warning light emitting diode, for example arranged in the driver's cab, to form a clogging alarm electrical circuit. FIG. 3 shows a clogging alarm electric circuit 20, which includes a light emitting diode 14.
, phototransistor 15, warning light emitting diode F22,
It consists of load resistors 23 and 24, a power supply 21 and a switch 25. Note that the portion surrounded by a broken line corresponds to the circuit of the light emitting body 3, and the broken line between the light emitting diode 14 and the phototransistor 15 indicates the above-mentioned optical path.

In FIGS. 1, 2, and 3, when the engine starts, the switch 25 of the circuit 20 is turned on, and current flows through the light emitting diode 14 of the support 11 of the light emitter 3, causing the diode to emit light. It is blocked by the body 4 and does not reach the phototransistor 15. In response to clogging of the filter element, the pressure inside the negative pressure chamber 8 of the clogging detection device 10 is reduced.

2, the bellows 2 is moved downward. When the negative pressure in the atmospheric pressure chamber 8 reaches a set value, the upper end of the shielding plate 4 moves below the optical path connecting the light emitting diode 14 and the phototransistor 15, and the light beam from the light emitting diode 14 reaches the phototransistor 15. . The phototransistor 15 illuminated with light starts to operate, and the warning light emitting diode 22
2. A current is supplied to cause the diode to emit light to warn of a clogging condition.

As described above, the clogging detection device St of the present invention has a structure that detects the clogging state by interrupting and communicating the optical path, and does not have a switching contact of a mechanical structure. No conduction failure occurs due to the number ζ, and stable operation can be achieved over a long period of time.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the clogging detection device of the present invention, FIG. 2 is a perspective view of the light emitter shown in FIG. 1, and FIG. 3 is a clogging alarm electric circuit. l--Casing 5--Spring 2--Bellows 14--Light emitting diode 3--Light emitter 15--Photo Transistor 4... Shield body O1 diagram

Claims (1)

[Claims] A bellows is disposed inside the casing to divide the inside of the casing into a negative pressure chamber and an atmosphere communication chamber, and a light emitting diode and a phototransistor are placed facing each other in the atmosphere communication chamber to form an optical path between them. A clogging detection device for an air cleaner, wherein a grounded shielding plate is disposed in the optical path, and a clogging state is detected by blocking and communicating the optical path by moving the bellows.