JPH03217284A - Heater for vapor cleaning tank - Google Patents

Abstract

PURPOSE:To stably keep the temp. of a liq. phase at a set temp. by providing two lines of a heater tube for passing a heating medium and sizing one line for raising the temp. of the liq. phase and the other for keeping the temp. of the liq. phase. CONSTITUTION:When the liq. phase 6 is heated close to the b.p. from room temp. at the start, etc., a large-heat-quantity solenoid valve 3 and a small-heat- quantity solenoid valve 5 are fully opened. A heating medium is then passed through a large-heat-quantity heater tube 2 and a small-heat-quantity heater tube 4. When the heating of the liq. phase 6 is completed, the solenoid valve 3 is fully closed. The solenoid valve 5 is fully opened based on a signal from a temp. switch when the temp. is lowered, and fully closed when the temp. is raised. A simple control loop is formed in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application] The present invention relates to a heating device for a steam cleaning tank. More particularly, the present invention relates to an apparatus for heating a liquid phase of a cleaning medium using a heating medium.

[Conventional technology] As a pre-treatment for painting resin products, etc.
The object to be coated is steam cleaned.

The cleaning medium used in steam cleaning is one that cleans the surface of the object to be coated to remove dirt and activates the surface of the object to improve the adhesion of paint. For example, it has a low boiling point (74.
1.1.1-}lichloroethane (hereinafter simply referred to as T
Steam cleaning agents such as CP) are used.

The cleaning medium is heated in a steam cleaning tank, and the object to be coated is introduced into the generated steam and steam cleaned.

FIG. 2 is a schematic cross-sectional view showing a steam cleaning tank and a conventional heating device.

At the bottom of the steam cleaning tank 01), one system of heater tubes Oz through which the heating medium is passed is arranged, and the liquid phase 0 of the cleaning medium is heated so that the liquid level is at the height where the heater tube a2J is immersed. It is formed.

Although not shown, a temperature detector is disposed in the liquid phase ae, and a temperature regulating valve U whose opening degree is controlled based on the detected temperature is provided in the heater tube. The vapor of the cleaning medium that has been heated to near its boiling point and evaporated is in the vapor phase O.
However, the rising steam is cooled by the cooling water pipe located at the top of the steam cleaning tank (formerly) and recondensed, forming a liquid phase O.
flows down to e. In this way, a steam surface 0g is formed at the upper part of the steam cleaning tank 01), and the height of the steam surface 09 is maintained within a predetermined range by controlling the temperature of the liquid phase aG described above.

The heater tube C2J and the temperature control valve (self) constitute a heating device for a steam cleaning tank. A heating medium such as water vapor is passed through the heater tube (+21), and the amount of heat supplied is controlled by changing the flow rate of the medium by a temperature control valve 031 according to the liquid phase Oe temperature.

However, compared to the amount of heat required to heat the liquid phase Oe at room temperature to the boiling point within a desired time at the start of work, for example, the amount of heat required to maintain the liquid temperature after reaching the boiling point is Since it is much smaller, the temperature control valve 0
31 is too large for maintaining the liquid temperature, and the liquid phase temperature fluctuates greatly across the set temperature.

In addition, a temperature control valve requires a controller in addition to a temperature detector (transmitter), making system adjustments complicated.

[Problems to be Solved by the Invention] The present invention has been made in view of the problems with the conventional heating device for a steam cleaning tank, and has a simple structure that can stably maintain the liquid phase temperature at a set temperature. An object of the present invention is to provide a heating device for a steam cleaning tank.

``Means for Solving the Problems'' The present invention has two systems of heater tubes that are installed in the liquid phase of the cleaning medium and pass the heating medium through them, one for increasing the liquid phase temperature and the other for maintaining the liquid phase temperature, respectively. The present invention relates to a heating device for a steam cleaning tank, in which the two heater tubes are each provided with an on-off valve for fully opening or fully closing a heating medium flow path.

Note that when the liquid temperature rises, if not only the liquid temperature raising system but also the liquid temperature maintaining system is used, the time required to raise the temperature will be shortened, so sizing may be performed with such an operating method in mind.

[Function] In the heating device of the present invention, the system for maintaining the liquid temperature is provided independently from the system for increasing the liquid temperature, so that the sizing can be optimized.

In addition, the liquidus temperature in the case of liquid temperature maintenance is determined by the liquid temperature maintenance system (
Since this is done by fully opening or fully closing the on-off valve of the small calorific value system, the return to the set value is quick and the liquid phase temperature does not fluctuate greatly.

Furthermore, since no regulating valve is used, a controller is not required, and the on-off valve can be fully opened or closed using a temperature switch or the like, resulting in a simple configuration.

In addition, in the event that one system's heater tube becomes unusable due to a fire, etc., it can be backed up by the other system.

[Embodiment] Next, a heating device for a steam cleaning tank according to the present invention will be explained based on the drawings.

FIG. 1 is a schematic sectional view showing an example of a heating device for a steam cleaning tank according to the present invention.

The steam cleaning 11 (11 itself is not particularly different from that shown in FIG. 2; a liquid phase (6) of the cleaning medium is formed at the bottom, and a vapor phase (6) of the cleaning medium is formed above the liquid level (7). 8)
The steam level (9) is maintained near the height of the upper cooling water pipe.

The heating device of the present invention shown in FIG. 1 is used as a heater tube that is installed in the liquid phase (6) of a cleaning medium such as TCP and passes a heating medium such as water vapor for use in large amounts of heat (for increasing the temperature of the liquid phase). It has two systems: a heater tube (2) and a heater tube (4) for a small amount of heat (for maintaining liquidus temperature). Furthermore, these two systems of heater tubes are respectively provided with a large heat quantity solenoid valve (3) and a small heat quantity solenoid valve (5) as on-off valves that are fully opened or fully closed.

When raising the liquid phase (6) temperature from room temperature to near the boiling point, such as when starting work, both the large heat quantity solenoid valve (3) and the small heat quantity solenoid valve (5) are fully opened, and the large heat quantity heater tube C2 and Flow the heating medium through the small heat quantity heater tube (4).

After completing the heating of the liquid phase (6), close the large heat solenoid valve (
3) is fully closed. Although not shown, a temperature switch is disposed in the liquid phase (6) and is set to operate at a temperature slightly higher and slightly lower than the desired liquid temperature. Based on the signal from this temperature switch,
The small heat quantity solenoid valve (5) is controlled to be fully open when the temperature is low and fully closed when the temperature is high. The small heat supply system is sized to supply slightly more heat than is necessary to maintain the liquid temperature (latent heat of vaporization and heat dissipation to the surroundings), so the temperature of the liquid phase (6) is maintained at the desired value. Stable and maintained.

[Effects of the Invention] As described above, the heating device of the present invention has a liquid temperature maintenance system that can supply a slightly higher amount of heat than the amount of heat required to maintain the liquid temperature, and this system prevents deviation from the desired liquid temperature. Since the liquid temperature is controlled by turning on and off based on the temperature, the liquid temperature is stably maintained without greatly deviating from the desired value.

Furthermore, since no regulating valve or controller is used, the control loop is easy to adjust and has a simple configuration.

Furthermore, even if the heater tube of one system becomes unusable due to cracks, etc., it can be backed up by the other system.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view showing an example of a heating device for a steam cleaning tank according to the present invention, and FIG. 2 is a schematic sectional view showing a conventional heating device. (Main symbols in the drawing) (2) Heater tube for two large amounts of heat (3) Solenoid valve for two large amounts of heat (4): Heater tube for small amount of heat (5): Solenoid valve for small amount of heat Solenoid valve for small amount of heat 1 Diagram small Heater for heat → Ubuo heater for silent use → Ubuo 2 diagram

Claims (1)

[Claims] 1 It has two systems of heater tubes that are installed in the liquid phase of the cleaning medium and allow the heating medium to pass therethrough.One system is sized for increasing the liquidus temperature and the other is sized for maintaining the liquidus temperature, and the heating medium is connected to the two systems of heater tubes. A heating device for a steam cleaning tank, which is provided with on-off valves that fully open or close a flow path.