JP2004163047A - Air heating apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an air heating apparatus for preventing condensate from residing inside the heating apparatus after operation stop. <P>SOLUTION: A steam supply pipe 2 is connected to an inlet header 8 of the heat exchanger 1. An air blow pipe 4 is connected to the side of the inlet header 8 of the steam supply pipe 2. A steam trap 5 is connected to an outlet header 9 of the heat exchanger 1. An on/off valve 6 is mounted in parallel with the steam trap 5. After the operation stop of the heat exchanger 1, the condensate residing in the heat exchanger 1 does not reside inside by blowing using high-pressure compressed air being supplied from the air blow pipe 4. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an air heating device that heats air using steam as a heat source, and more particularly to an air heating device that does not accumulate condensed water as steam condensed water inside the heating device.
[0002]
[Prior art]
[Patent Document 1] Japanese Patent Publication No. 51-31998 discloses an air heating apparatus using a fin tube type heat exchanger, in which the amount of steam supplied to the heating apparatus is controlled by an adjusting valve and the heating apparatus is checked. The valve and the thermal valve are used in combination to prevent the check valve from opening when the inside of the heating device is evacuated and sucking outside air into the heating device to prevent the condensate from being discharged.
[0003]
[Problems to be solved by the invention]
The conventional air heating device has a problem that the condensate in the heating device cannot be completely discharged. That is, when the inside of the heating device becomes a vacuum, the outside air is sucked in, and the differential pressure between the inlet side and the outlet side of the steam trap for discharging the condensate can be prevented from becoming a negative pressure. The pressure on the outlet side is both atmospheric pressure and the substantial differential pressure remains zero, so that the condensate remaining in the concave portion or the thin tube portion inside the heating device cannot be discharged to the outside.
[0004]
If condensed water stays inside the heating device, the condensate will continue to stay until the next operation of the heating device, corroding the inside of the heating device and possibly damaging the fin tube by making a hole in the fin tube.
[0005]
Accordingly, an object of the present invention is to provide an air heating device that does not cause condensate to stay inside the heating device after the operation is stopped.
[0006]
[Means for Solving the Problems]
Means for solving the above problem is to heat air passing through the heat exchanger with heating steam supplied through a control valve, and to condensate condensed by the steam being deprived of heat by a steam trap. In this system, an on-off valve is attached in parallel with the steam trap, and an air blow pipe for supplying compressed air to the inside of the heat exchanger and blowing it is connected.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
After the operation of the heating device is stopped, the on-off valve installed in parallel with the steam trap is opened, and compressed air is supplied from the air blow pipe to the inside of the heat exchanger. The condensed water that has been blown and remains in the concave portion and the thin tube portion is reliably removed to the outside.
[0008]
【Example】
In this embodiment, a heat exchanger 1 for heating the passing air, a steam supply pipe 2 for supplying steam to the heat exchanger 1, a control valve 3 attached to the steam supply pipe 2, An air blow pipe 4 connected to the inlet side, a steam trap 5 connected to the outlet side of the heat exchanger 1, an on-off valve 6 mounted in parallel with the steam trap 5, and an outlet side of the steam trap 5 and the on-off valve 6 And the vacuum pump 7 connected thereto constitute an air heating device.
[0009]
An inlet header 8 is arranged on the left side of the heat exchanger 1 and connected to the steam supply pipe 2, and an outlet header 9 is arranged on the right side and connected to the steam trap 5. The steam supplied from the steam supply pipe 2 passes through the entire fin tube (not shown) in the heat exchanger 1 from the inlet header 8, exchanges heat with air to be condensed, and flows through the steam trap 5 from the outlet header 9. Then, it is sucked by the vacuum pump 7 and discharged to the outside.
[0010]
A control valve 10 for controlling the amount of compressed air to be supplied is attached to the air blow pipe 4. In this embodiment, the example in which the air blow pipe 4 is connected to the heat exchanger 1 side of the steam supply pipe 2 has been described, but the air blow pipe 4 can be connected to the upper end of the inlet header 8.
[0011]
The control valves 3 and 10 and the opening / closing valve 6 are connected to a control unit (not shown), and the valve opening or the opening / closing of the valve is automatically controlled according to a signal from the control unit.
[0012]
When air is heated by the heat exchanger 1, the air flowing down the heat exchanger 1 is heated by steam at a predetermined pressure supplied from the steam supply pipe 2 and the inlet header 8. The steam deprived of heat by heating becomes condensed water and is removed from the steam trap 5 and the vacuum pump 7 to the outside of the system.
[0013]
When the supply of steam from the steam supply pipe 2 is stopped and the heat exchanger 1 is stopped, the on-off valve 6 is opened and compressed air of a predetermined pressure is supplied from the control valve 10 to the inside of the heat exchanger 1. As a result, the condensate remaining in the concave portion or the thin tube portion in the heat exchanger 1 is blown to the outside through the on-off valve 6 and the vacuum pump 7 without fail and does not remain in the heat exchanger 1. .
[0014]
In the present embodiment, an example is shown in which the vacuum pump 7 is connected to the outlet side of the steam trap 5 and the on-off valve 6. The vacuum pump 7 is not always necessary.
[0015]
【The invention's effect】
According to the present invention, by supplying compressed air from the air blow pipe to the inside of the heat exchanger, residual condensate remaining in the heating device after the operation is stopped can be reliably discharged to the outside of the system.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing an embodiment of an air heating device of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Heat exchanger 2 Steam supply pipe 3 Control valve 4 Air blow pipe 5 Steam trap 6 On / off valve 8 Inlet header 9 Outlet header

Claims (1)

The air passing through the heat exchanger is heated by heating steam supplied through a control valve, and steam is deprived of heat and condensed water is discharged from the steam trap to the outside. An air heating device, wherein an on-off valve is attached in parallel, and an air blow pipe for supplying compressed air to the inside of the heat exchanger and blowing it is connected.

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