JPS59177155A - Method for raising temperature of fluid - Google Patents

Abstract

PURPOSE:To uniformize temp. distribution and to dispense with an external heat source, by raising the temp. of a fluid by forcibly flowing the fluid through an orifice while pressurizing the same. CONSTITUTION:A pressure gauge 5, for example, three orifices 6, a valve 7 and a spray gun 8 are provided to a supply pipe 3 in the order near to a pump 4. The paint 2 in a tank 1 is sent into the supply pipe 3 by the pump 4 and when it is confirmed by the pressure gauge 5 that the pressurizing force to the paint 2 is predetermined pressure, the valve 7 is opened to flow the paint 2 to the direction shown by the arrow. The pressure of the paint is lowered every time it passes the orifices 6 by the throttling resistances of said orifices 6 and, at the same time, the temp. of said paint 2 is raised. In this case, a fluid is not limited to the paint and this method can be applied to other fluid.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a method of increasing the temperature of a fluid.

As is well known, the viscosity of a fluid is related to temperature, with lower viscosity at higher temperatures and higher viscosity at lower temperatures. These characteristics are the same for spray paints that are mainly made of resin or pigments, but when the temperature of this type of paint is low and its viscosity is high, the sample becomes a mist and is sprayed from the nozzle. There is a problem that the so-called sprayability deteriorates, a large amount of paint adheres to the tip of the spray nozzle, and the painted surface becomes rough. For this reason, in order to lower the viscosity of the paint, paint has been heated to raise its temperature, and the method shown in FIG. 1 is known as a heating method. That is, in a feeding device configured to send paint 2 in a tank 1 to a spray nozzle (not shown) via a feeding pipe 3 and a pump 4, a nichrome wire is attached to the outer circumferential side of the feeding pipe 3. An electric heater 5 consisting of etc. is provided,
The paint 2 is heated by an electric heater 5 while flowing through the feed pipe 3. However, the conventional temperature raising method described above has the following problems.

In other words, while a large amount of flammable organic solvent is generally used in the painting process, the conventional electric heater 5 generates heat at a temperature higher than the flash point of the organic solvent. The container 5 must have an almost completely explosion-proof structure, and even if it has an explosion-proof structure, it is difficult to completely eliminate the risk of fire. In addition, the paint 2 has a low thermal conductivity and the flow velocity within the feed pipe 3 is faster at the center. On the contrary, if the temperature of the electric heater 5 is raised to sufficiently raise the temperature of the paint 2 flowing through the center of the feed pipe 3, 3
There is a problem in that the paint 2 in contact with the inner circumferential surface of the tank gels, clogging the feed pipe 3 and nozzles, and further increases power consumption. Furthermore, as mentioned above, if there is a large temperature difference between the inner wall and the center of the feed pipe 3, and a correspondingly large difference in viscosity, there will be a difference in the particle size of the paint mist.
As a result, there were problems such as uneven painting and roughening of the painted surface.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a method in which the temperature distribution is substantially uniform and the temperature can be safely raised without using an external heat source.

The present invention is characterized in that the temperature of the fluid is increased by pressurizing the fluid and forcing it to flow through the orifice.

An embodiment of the present invention will be described below with reference to FIG. FIG. 2 is a schematic diagram of an apparatus for carrying out the present invention.
The same reference numerals as in FIG. 1 are given to the figures. In other words, in the feed pipe 3,
Pressure gauges 5, multiple (3 in Figure 2) in order of proximity to pump 4
An orifice 6, a valve 7, and a spray gun 8 are installed in this order. Therefore, in the above-mentioned apparatus, the paint 2 in the tank 1 is fed into the feed pipe 3 by the pump 4.

At this time, it is confirmed by the pressure gauge 5 whether the pressure applied to the paint 2 is a predetermined pressure. When the paint 2 at a predetermined pressure flows through the feed pipe 3 in this manner, the flow of the paint 2 is throttled by the orifice and the chair 6. Therefore, the pressure of the paint 2 decreases due to the throttle resistance of the orifice 6, and at the same time the temperature of the paint F31-2 increases. This is thought to be caused by friction between the paint 2 and the feed pipe 3, a change in the state of the paint 2, or both, but in any case, the paint 2 passes through the first to third orifices 6. Each time, the pressure decreases slightly and the temperature increases slightly. Note that the temperature increase caused by the orifice 6 varies depending on factors such as the initial pressure, the outside temperature, and the inner diameter of the orifice, as will be described later. The number of orifices, etc. may be determined experimentally.

Next, Table 1 shows the results of an experiment using a vinyl chloride sol with a viscosity of 300 P/at 20° C. as a sample.

As is clear from Table 1, it was strongly recognized that the temperature of the sample increased by using the orifice, and it was also recognized that the increased temperature became higher as the initial pressure was higher.

It goes without saying that the present invention can also be applied to cases in which fluids other than paint are heated.

As is clear from the above explanation, this invention [well, since the fluid is pressurized and forced to flow through the orifice, there is no need for a high-temperature external heat source such as an electric heater. If the temperature is increased, the risk of fire can be eliminated.

In addition, since the fluid substantially generates heat by itself and raises its temperature, the fluid itself can be raised evenly, and there is no risk of overheating as in conventional methods using an external heat source.
Therefore, when using fluid force 1 spray paint, there may be problems such as uneven temperature (this may cause deterioration of the spray quality, gelation of the feed pipe, blockage of the spray nozzle, or spots on the painted surface, etc.). This can be prevented.

[Brief explanation of drawings]

FIG. 1 is a schematic system diagram of an apparatus for implementing the conventional method, and FIG. 2 is a schematic system diagram of an apparatus for implementing the method of the present invention. 2...Paint, 3...Feeding pipe, 5...Pump,
6... Orifice. Applicant Toyota Motor Corporation Representative Patent Attorney Yutaka 1) Hisashi Take (one idiot)

Claims (1)

[Claims] By pressurizing the fluid and forcing it through the orifice,
A method for increasing the temperature of a fluid, characterized by increasing the temperature of the fluid.