JPH0138710Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a test device used for supplying smoke to a smoke detector to perform an operation test or a sensitivity test.

Used to test the operation or sensitivity of smoke detectors, such as ionization smoke detectors and photoelectric smoke detectors, which conventionally detect the occurrence of fire by detecting smoke, by exposing them to a smoke atmosphere. There is testing equipment. For example, there are methods that use smoke rising from incense sticks, or mist generated from a spray filled with Freon gas. However, the former type of incense sticks may be avoided due to their odor and cannot be used in places where open flames are strictly prohibited, and the latter type of incense sticks have recently been The toxicity of this gas has become a problem in the United States and other countries, and there is currently hesitation in its use.

Therefore, the present applicant first applied for patent application No. 1 in 1982.
In No. 61474 (Japanese Unexamined Patent Publication No. 59-186093), we proposed a new testing device to solve the above problems all at once.

Specifically, liquid paraffin, which is odorless and harmless at room temperature, is atomized by ultrasonic vibration, and the test is conducted by supplying the generated liquid paraffin mist to a smoke detector.

However, it was discovered that the liquid paraffin mist generated by the previously proposed test device had different characteristics from the real smoke obtained by smoking. This difference is not a problem in an operation test that simply tests whether the device operates regardless of the smoke concentration, but it becomes a serious problem in a sensitivity test where the smoke concentration at which the device operates is accurately determined. This difference is particularly noticeable in scattered light type smoke detectors. This is due to the fact that when measuring the characteristics of a scattered light type smoke detector, a transmitted light type smoke densitometer is used as a reference standard for measuring smoke concentration. In other words, the intensity of scattered light is proportional to the sixth power of the particle size according to Mie's law, whereas the liquid paraffin mist obtained by ultrasonic vibration contains particles as large as 0.5 μm. This caused a transmitted light smoke densitometer to obtain a large output signal with liquid paraffin fog, even if the smoke density was the same as real smoke.

Therefore, in the test device according to this invention, by providing a condensation section that removes coarse particles in the liquid paraffin mist, it is possible to obtain a mist that has properties almost the same as real smoke, thereby making it possible to conduct accurate sensitivity tests. This will be explained in detail below based on the drawings.

1 and 2 are a longitudinal cross-sectional view and a cross-sectional view taken along the line A-A' of an embodiment of the test device according to this invention. accommodating part 2 and this accommodating part 2
It consists of a mist generating section 3 that supplies a mist of liquid paraffin into the interior. A circulation fan 4, a rectifying plate 5, and a rectifying wire mesh 6 are provided inside the housing part 2 to circulate and rectify the air inside. Further, the accommodation section 2 is provided with a transmitted light type smoke densitometer consisting of a light emitter 7 and a light receiver 8, and is used for setting the measured smoke concentration of the test device. As is clear from FIG. 3, which shows a vertical cross-sectional view, the mist generating section 3 includes an atomizing section that atomizes the liquid paraffin 9 by ultrasonic vibration of a piezoelectric vibrator 10;
It consists of a delivery section consisting of an electric fan 12 that sends out liquid paraffin mist 11 generated in the atomization section to the storage section 2 . To explain in more detail, the atomizing section has liquid paraffin 9 in a liquid tank 14, which is supplied from a replenishment tank 13 and whose liquid level is always kept constant.
is atomized by ultrasonic vibration of a piezoelectric vibrator 10 provided at the bottom. The liquid paraffin mist 11 atomized in this way and staying in the space above the liquid tank 14 is transported by the transport air supplied from the transport air supply port 15 bored in the side wall at the top of the liquid tank 14. Storage part 2 from pipe 16
sent to. Note that the upper half of this conveying pipe 16 is separable, making it easy to attach and remove it from the storage section 2. Above electric fan 1
2 is installed at the bottom of the housing 17, and an oscillation circuit section 18 for driving the piezoelectric vibrator 10 is installed around it.

A suitable number of mesh screens 19 are installed in the conveying pipe 16 to allow only liquid paraffin mist having a particle size smaller than 0.2 μm to pass therethrough.

In order to conduct a sensitivity test of a smoke detector using the test device of this invention configured as described above, the oscillation circuit section 18 is activated to bring the piezoelectric vibrator 10 into an ultrasonic vibration state, and the inside of the liquid tank 14 is At the same time, the electric fan 12 is operated to supply conveying air from the conveying air supply port 15 into the liquid tank 14, and the liquid paraffin mist 11 staying in the liquid tank 14 is accommodated. Send to section 2. At this time, the liquid paraffin mist 11 passes through the mesh screen 19 in the conveying pipe 16, but the particle size is 0.2 μm.
Larger fog particles adhere to and condense on this mesh screen 19, and then the liquid paraffin 9 in the liquid tank 14
will be reduced to Therefore, the fog rising from the fog generating section 3 has a particle size smaller than 0.2 μm, and has properties almost the same as real smoke.

The mist sent from the fog generating section 3 into the storage section 2 in this way is sent to the rectifying plate 5 by the circulation fan 4, and after being rectified through the rectifying wire mesh 6, it is circulated within the storage section 2. I come to do it. This circulation makes the concentration distribution in the storage section 2 uniform. Therefore,
Measure the concentration using the transmitted light type smoke densitometers 7 and 8, and when the specified concentration is reached, the smoke sensor D to be measured is
is placed in the storage section 2 and measured.

In the above embodiment, a mesh screen 19 was used as the condensing section, but other structures are also possible, although there may be slight differences in efficiency and performance. For example, although the entire device is slightly larger, the conveyor pipe 1
6 is elongated and heavy particles with a large particle size are allowed to fall naturally, or the structure uses a plurality of concentrically arranged cylindrical bodies as shown in FIGS. 4 and 5.

That is, FIGS. 4 and 5 are a partial cross-sectional view and a plan view of another embodiment of the test apparatus according to this invention, and in the conveying pipe 16, three cylindrical bodies having mutually different diameters are shown. 20 are arranged concentrically to form a condensation section. When the liquid paraffin mist 11 atomized by the ultrasonic vibration of the piezoelectric vibrator 10 passes through the gap 21 formed between the cylindrical bodies 20, particles with large particle size Only those particles that adhere to the surface of the cylindrical body 20 and have a small particle size are delivered to the storage section. The number and length of the cylindrical bodies 20 to be installed are determined based on the total amount to be carried out.

As described above, according to the test device of this invention, it is possible to obtain liquid paraffin mist, which is odorless and harmless at room temperature, and whose properties are almost the same as real smoke, making it particularly suitable for sensitivity tests of smoke detectors. There is a lot to contribute.

[Brief explanation of drawings]

1 and 2 are a longitudinal cross-sectional view and a cross-sectional view taken along the line A-A' in one embodiment of this invention, FIG. 3 is a longitudinal cross-sectional view of the fog generating section 3 in the above-mentioned embodiment, and FIG. FIG. 5 is a partial sectional view and a plan view of a mist generating section in another embodiment of the invention, and the same parts are designated by the same reference numerals throughout the figures. D...Smoke detector, 2...Accommodation section, 9...Liquid paraffin, 10...Piezoelectric vibrator, 11...Fog of liquid paraffin, 12...Electric fan, 19...Mesh screen, 16... Conveyance pipe, 20...
Cylindrical body.

Claims (1)

[Claims for Utility Model Registration] (1) A storage unit that accommodates a smoke detector and an atomizing unit that atomizes liquid paraffin by ultrasonic vibration, and a liquid paraffin mist generated in the atomizing unit. A test device for a smoke detector configured to send liquid paraffin to the storage section, characterized in that a condensation section is provided between the storage section and the atomization section to remove coarse particles in the liquid paraffin mist. Smoke detector test equipment. (2) The test device for a smoke detector according to claim 1, wherein the condensation part is a mesh screen. (3) The test device for a smoke detector according to claim 1, wherein the condensing part is a long cylindrical body. (4) The test device for a smoke detector according to claim 1, wherein the condensing portion is a plurality of concentrically arranged cylindrical bodies.