JPH06186130A - Smoke generator - Google Patents

Abstract

PURPOSE:To provide a smoke generator wherein smoke used to measure the flow of a gas is generated steadily and in large quantities. CONSTITUTION:A liquid such as polypropylene glycol or the like is set to a pressurized and heated state, it is spouted to the space of a cooling tank 6 which has been cooled by a nozzle 5 and which contains the air, foggy fine particles are generated from the liquid which has been gasified and smoke is discharged from a spraying port 14 communicating with a measuring space. A liquid-collecting valve 13 and a blower 9 which sends the cooling air are attached to the cooling tank 6. The pressurized and heated state is maintained to be definite by a temperature sensor, a pressure sensor and an electric control device which are attached.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a smoke generator for generating smoke which is used to detect the flow of gas visually or by other means.

[0002]

BACKGROUND OF THE INVENTION Smoke generators of this kind are used for investigating the gas flow around an object of interest or in a room or space of a special building. In that case, by emitting smoke-like fine particles, it is possible to detect a gas flow (air flow) that is not normally visible under the above-mentioned circumstances.

In conventional smoke generators, heat is applied to specific oils such as ondina oil and kerosene to thermally decompose the oils, and fine particles of the decomposed substances, that is, smoke is released into the gas. It was Since this type of smoke generator is suitable for easily generating smoke, it has been widely used in wind tunnel tests, for example. Even if the above oil is already toxic or non-toxic, some of the various thermal decomposition components produced by thermal decomposition are toxic or harmful to the human body.

[0004] In addition, as unfavorable characteristics, there is a foul odor, which causes unpleasant pain to the human body and physical and mental health problems if it is continuously used, and it causes illness or sequelae because it is toxic. Adheres to the members around the air flow passage, but it is extremely difficult to remove or clean this pyrolyzed component, which causes serious damage or malfunction to the equipment used in air flow related tests and attached measuring instruments. Something that is feared is known.

[0005]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to easily clean smoke components adhering to equipment or attached measuring equipment without causing harmful smoke to be generated.
Moreover, it is an object of the present invention to provide a novel smoke generator capable of efficiently and constantly generating smoke.

[0006]

SUMMARY OF THE INVENTION According to the present invention, the above-mentioned problems are solved in the first part consisting of a storage container 1 for storing a liquid for smoke generation and a pressure pump 2 connected to this container, and the pressure pump 2. A second part consisting of a heating tank 3 containing a heater 4 connected via a conduit and a jet nozzle 5 connected to this heating tank 3, a cooling tank 6 having a jet nozzle on the side wall, and cooling on the side wall facing the jet nozzle. A block 7, a lower part of the cooling tank 6 is used as a drain tank for liquid recovery, and a drain recovery valve 13 and a spray port 14 for discharging the smoke of the liquid emitted in the cooling tank 6 are provided at the lowermost part thereof. A temperature sensor S _T and a pressure sensor S _P that are composed of three parts and a fourth part that introduces the air taken in through the blower 9 into the cooling tank 6 and that measures the temperature and pressure of the liquid in the heating tank 3. By liquid The above problem is solved by a smoke generator equipped with electric control units 20 and 22 attached to the pressurizing pump 2 and the heater 4 in order to heat the pressurizing unit to a predetermined temperature state that does not boil under a predetermined pressurizing state.

Further advantageous configurations according to the invention are described in the dependent claims.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail based on the illustrated embodiments. A smoke generator according to the invention is shown schematically in FIG. The main part can be divided into four parts which are connected to each other. That is, the first part that stores and supplies the liquid that becomes the raw material of smoke, the second part that heats the supplied liquid to spray it, and the third part that temporarily stores and discharges the sprayed smoke and becomes the generating container. And a fourth part having a ventilation function to assist the emission of smoke in the generating container part.

In the first part, there is provided a pressurizing pump 2 which is connected to a liquid storage container 1 which is a raw material for forming smoke through a liquid conduit. In the second part, the liquid is supplied from the pressurizing pump 2 to the heating tank 3 via the liquid conduit in a pressurized state. The heating tank 3 does not include air or a vaporized vapor phase component of the liquid of the raw material in a state where the liquid serving as the smoke raw material is completely sealed (in other words, an air layer is formed above the heating tank 3). Filled (without).
The heating tank 3 is provided with a heater 4 for heating the liquid introduced under pressure to a predetermined temperature and constantly maintaining this temperature. Further, the heating tank 3 is connected with a nozzle 5 for ejecting a liquid. The liquid in the heating tank 3 is heated to the extent that boiling or bumping does not occur under pressure.

In the third part, a cylindrical cooling tank 6 which is the main body of the smoke generator is provided, and the lower portion of this cooling tank 6 is a drain tank 12. The liquid to be discharged that has not become smoke can be discharged from the drain tank 12 to the outside of the cooling tank 6 via the drain recovery valve 13. According to the present invention, a considerable amount of the liquid ejected from the nozzle 5 attached to the side wall of the cooling tank 6 hits the facing portion of the side wall, that is, the cooling block 7 shown in the figure. The heated jet liquid hits the cooling block 7,
In order to prevent the heat of this liquid from being introduced into the cooling tank 6, the cooling block 7 is provided with cooling means 7 for forcibly cooling this portion. The heated liquid discharged from the nozzle 5 and the vaporized gas accompanying it are cooled in the internal space of the cooling tank 6 to generate a large amount of mist-like fine particles, that is, smoke. The generated smoke is guided to the spray port 14 by the air introduced with the help of the blower of the fourth part described below, and outside the cooling tank 6,
In other words, it is led to a space (not shown) in which the object to be tested is installed.

In the fourth part, a blower 9 is provided for sending air from the outside into the cooling tank 6. Further, in the case of this embodiment, a heat exchange section 10 for cooling the air is provided in order to generate a large amount of smoke. The air supplied from the blower 9 passes through the heat exchange section 10 and the attached air conduit,
The cooled air is introduced into the cooling tank 6. The cooled air is used to rapidly cool the gas generated from the heated liquid rapidly ejected from the nozzle 5 to form atomized fine particles. As is well known, the heat exchange section 10 can adopt a heat exchange method using gas or liquid, but since the resistance of the air flow in this section is large, a powerful fan or compressor is usually used as the blower 9.

The heat exchange section 10 described above can be omitted if the amount of smoke generated is relatively small. That is, the air may be sent directly from the blower 9 to the cooling tank 6 without using the heat exchange section 10 shown in FIG.

In order to control the discharge flow rate of the smoke sprayed by the smoke generator having the above-described structure, the heating tank 3 is properly operated to vary the smoke generation amount, as will be described later in detail. Alternatively, the flow rate of the air introduced from the blower 9 can be varied. If necessary, a valve for adjusting the flow rate or a slit having a variable aperture may be provided in the spray passage C ₁ of the spray port 14 to change the flow rate of smoke emitted.

Further, it is advantageous to add a filter and a dehumidifier known per se to the air suction port C ₂ so as to prevent unwanted dust, dust or the like from entering the air introduced from the blower 9.

In the above description, the size of the cooling block 7 is
Since the size of the region where the liquid directly sprayed from the nozzle 5 hits is sufficient, a material having a relatively large heat capacity and a high thermal conductivity, such as copper or its alloy, is suitable for this portion. The cooling means 8 used for forcibly cooling the cooling block 7 includes the cooling block 7
Water cooling system with a metal conduit for cooling water directly welded to the cooling block, an air cooling system in which air is blown to the cooling block 7 with an appropriate blower, or a Peltier element that converts electric current into heat is attached to the cooling block 7 to cool it electrically. A cooling method can be adopted.

Since high-temperature steam is ejected inside the cooling tank 6, the temperature of the wall of the cooling tank 6 easily rises. Cooling tank 6
When the temperature inside the tank rises, the vapor generated from the liquid ejected from the nozzle 5 is less likely to become a fog, so it is desirable to cool the wall of the cooling tank 6 as much as possible. When the flow rate of the generated smoke is relatively small, the wall of the cooling tank 6 is made of a material having a small heat capacity and a high thermal conductivity, such as aluminum, and natural heat dissipation by the outside air is sufficient. However, when a large amount of smoke is constantly generated, the above heat radiation method is not sufficient, and the wall of the cooling tank 6 must be forcibly cooled. For this purpose, a large number of fins may be attached to the wall of the cooling tank 6 and a blast cooling method in which cooled air is sent by a blower, or a water cooling method in which a jacket is attached to the wall of the cooling tank 6 and cooling water is circulated for cooling. .

Next, a mechanism for generating smoke in the smoke generator according to the present invention and a control method therefor will be described. As shown in FIG. 2, an electric control device is attached to control the pressurizing pump 2 and the heating tank 3. The main parts of this electric control device are a control arithmetic unit 20, a target value setting unit 22,
It is composed of a display unit 24 and an alarm unit 25.

A temperature sensor S _T and a pressure sensor S _P are mounted inside the heating tank 3 in order to maintain the temperature and pressure of the liquid inside the heating tank 3 at predetermined values.
The detection signals of both the sensors S _T and S _P are the conductors l _T and l, respectively.
It is introduced into the control arithmetic unit 20 via _P. On the other hand, target value signals corresponding to the target values of the liquid temperature and pressure are sent from the target value setting unit 22 to the conductors L ₁ and L, respectively.
₂ is introduced into the control arithmetic unit 20. The control calculation unit 20 compares the measured value and the target value relating to temperature and pressure, respectively, and outputs a drive signal to the heater 4 and the pressurizing pump 2 via the output leads L _H and L _P so that the difference between them is zero. Is constantly supplied to maintain the appropriate temperature and pressure.

The liquid in the heating tank 3 needs to be as hot as possible in order to vaporize as much as possible when ejected from the nozzle 5. However, if the liquid enclosed in the heating tank 3 boils or bumps, it becomes impossible to constantly supply and eject the liquid. Therefore, it is necessary to maintain the liquid in the heating tank 3 at a high pressure as much as possible. Further, according to this principle, there are certain limits on the required temperature and the required pressure. That is, if the temperature rises more than necessary or the pressure drops below the necessary amount, the heating tank 3
Boiling of liquid occurs inside. Further, when the temperature drops below the required level, the vaporization amount of the liquid ejected from the nozzle 5 decreases,
The amount of smoke generated is reduced. In addition, if the pressure rises more than necessary, the pressure resistance of the device will be exceeded, and damage may occur. In the target value setting unit 22, usable upper and lower limits for temperature and pressure are also inputted, and the conductors L ₁ and L _{2 are} similarly input.
Are respectively introduced into the control arithmetic unit 20 via.
When the measured temperature or pressure exceeds the upper limit value or the lower limit value, the control arithmetic unit 20 immediately sends an alarm signal to the lead wire L ₄
To the alarm unit 25, and at the same time, a control signal for instructing an emergency stop or interruption of the operation of the device is also supplied to the required device. The alarm in the alarm unit 25 is performed by any one of known acoustic means (for example, a speaker) and optical means (for example, an illumination lamp or a light emitting diode) or a combination thereof.

Incidentally, the actually measured temperature and pressure are introduced from the control arithmetic unit 20 into the display unit 24 through the conductor L ₃ , and if the values thereof can be visually observed,
It is particularly advantageous.

A part or all of the above-mentioned four functional blocks, the control arithmetic unit 20, the target value setting unit 22, the display unit 24 and the alarm unit 25 are replaced by a commercially available programmable control unit (an arithmetic operation mainly composed of EPROM). Unit). Also,
If necessary, a discrete element can be configured as a dedicated control unit. Control arithmetic unit 20
The comparison calculation function of (1) has a PID drive function, and performs feedback control of the fluctuation amount deviated from the target value toward the target value in an optimal state for the system. The target value setting unit 22 is composed of a keyboard, but simple numeric keys and some press keys (numerical signs and simple command keys)
Can be formed as a dedicated keyboard by itself.

As can be seen from FIG. 2, the pressure of the liquid in the heating tank 3 is determined by the outflow rate from the nozzle 5 and the supply capacity of the pressure pump 2. The outflow velocity of the nozzle 5 depends on the conductance of the nozzle (the inner diameter D _{N of} the nozzle, the length L _{N of the} nozzle).
And the viscosity of the liquid and the temperature of the liquid at that time). Taking these parameters into consideration, the pressure pump 2
It is necessary to design the heater 4 and the nozzle 5 to have an optimum size or capacity. In that case, it is necessary to make the amount of smoke generation appropriate according to the velocity of the measured airflow. For example, when measuring the air flow in a clean room, the flow velocity is 0.1 to 1 m / s.
However, the amount of smoke is relatively small. Also, when measuring the air flow around a moving vehicle, the flow velocity is usually 10-100.
It also becomes m / s, and the amount of smoke introduced increases accordingly.

The smoke generator according to the invention does not use smoke generation by pyrolysis. To the last, the atomized liquid is formed from the liquid that was initially charged, and this is used as smoke. It is particularly advantageous to use a water-soluble substance as the liquid used, for example propylene glycol (PEG: average molecular weight 70.09, boiling point 180 ° C. at atmospheric pressure). Then, in the heating tank 3, the propylene glycol liquid
It is used at 5 bar. Of course, propylene glycol is harmless to the human body, does not cause discomfort during use, and does not cause any damage to the equipment used. Above all, since it is water-soluble, it is possible to easily wash and remove the used substances attached to the equipment and auxiliary equipment during the experiment after the measurement.

The numerical values or specific examples used in the above description are not limited to them, but are used as examples for the sake of ease of description and specificity, and other various methods and configurations are possible. Is. Various modifications and changes can be made to the smoke generator described above. However, it goes without saying that all smoke generators having the configurations defined in the claims are within the scope of the present invention.

[0025]

As described above, the smoke generator according to the present invention can constantly and efficiently generate a large amount of smoke. Moreover, since the smoke generated by thermal decomposition is not used, the liquid itself used is harmless to the human body. Further, the raw material liquid used is water-soluble. It completely eliminates the various problems found in conventional smoke generators used in wind tunnel testing.

[Brief description of drawings]

FIG. 1 is a schematic layout diagram showing a main configuration of a smoke generator according to the present invention.

FIG. 2 is an accessory control circuit used to explain the mechanism of smoke generation and its control.

[Explanation of symbols]

1 Storage Container 2 Pressurizing Pump 3 Heating Tank 4 Heating Heater 5 Jet Nozzle 6 Cooling Tank 7 Cooling Block 8 Cooling Means 9 Blower 10 Heat Exchanger 11 Air Introduction Passage 12 Drain Tank 13 Drain Recovery Valve 14 Spray Port 20 Control Arithmetic Unit 22 Target value setting unit 24 Display unit 25 Alarm unit S _T Temperature sensor S _P Pressure sensor C ₁ Spray passage C ₂ Suction port

Claims (6)

[Claims] 1. A heating tank containing a first part consisting of a storage container 1 for storing a liquid for smoke generation and a pressurizing pump 2 connected to the container, and a heater 4 connected to the pressurizing pump 2 via a conduit. 3 and a second portion composed of the jet nozzle 5 connected to the heating tank 3, a cooling tank 6 having the jet nozzle on the side wall, a cooling block 7 on the side wall facing the jet nozzle, and a lower portion of the cooling tank 6 for collecting liquid. As the drain tank, the drain recovery valve 13 and the cooling tank 6 are provided at the bottom of the drain tank.
A spray port 1 for discharging the smoke of the liquid generated inside
A temperature sensor S _T that is composed of a third part including the fourth part and a fourth part that introduces the air taken in through the blower 9 into the cooling tank 6, and measures the temperature and pressure of the liquid in the heating tank 3.
And the pressure sensor S _P to heat the liquid to a predetermined temperature state in which the liquid does not boil under a predetermined pressure state.
And a smoke generator equipped with electric control devices 20, 22 attached to the heater 4. 2. A heat exchanger 10 for further cooling air is also attached to the fourth portion.
The smoke generator described in. 3. The cooling block 7 is provided with a cooling means 8 for any one of air cooling, water cooling, electrothermal conversion or a combination thereof for forced cooling. Or the smoke generator according to 2. 4. The outer wall of the cooling tank 6 is provided with other cooling means of air cooling or water cooling system different from the cooling means 8 for forced cooling.
The smoke generator according to any one of 3 above. 5. Further, a display unit 24 for displaying measured values of temperature and pressure being measured and a use limit range of liquid temperature and pressure are specified in the electric control devices 20, 22, and these The smoke generator according to any one of claims 1 to 4, further comprising an alarm unit which has a function of stopping the system when the limit value is exceeded and which issues an alarm. 6. The spray passage C ₁ of the spray port 14 is provided with variable flow rate means for controlling the flow rate of smoke to be emitted, according to any one of claims 1 to 5. Smoke generator.