JP2004016860A - Steam heating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steam heating method which can lower the heating temperature of steam with good response when the heating temperature of steam is lowered. <P>SOLUTION: A steam supply pipe 3 is connected to the jacket part 2 of a reaction vessel 1 and a steam control valve 4 is attached to the steam supply pipe 3. A suction means 8 is connected to the lower part of the jacket part 2 through a suction pipe 5. A steam trap 7 and an automatic on-off valve 6 are attached to the suction pipe 5. When the heating temperature of steam in the jacket part 2 is lowered, the pressure of steam supplied from the steam control valve 4 is lowered and the automatic on-off valve 6 is opened for a predetermined time to rapidly lower the heating temperature of steam of the jacket part 2. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for heating an object to be heated with steam, and more particularly to a steam heating method suitable for a case where the steam temperature is relatively low, such as about 40 ° C. to over 100 ° C. Specifically, it is a heating method such as a reaction kettle used for various chemical reactions and the like, a food distillation apparatus, a concentration apparatus, and a sterilization apparatus. In many cases, the objects to be heated of these apparatuses cause thermal damage or composition change due to a slight change in temperature, and it is necessary to accurately maintain the heating temperature.
[0002]
[Prior art]
As a conventional steam heating method, for example, there is a method using an apparatus disclosed in JP-A-10-2647. This involves connecting a steam supply pipe that supplies steam to the heating device, connecting a combination pump that sucks fluid in the heating device, and installing a steam trap and valve means in parallel between the combination pump and the heating device. Thus, when the heating temperature is changed, the heating can be performed with good responsiveness without causing a time delay.
[0003]
[Problems to be solved by the invention]
The above-described conventional steam heating method has a problem that it is not possible to change the heating temperature with good responsiveness when the heating temperature is changed. In particular, when the steam heating temperature is lowered, there is a problem that the response cannot be changed with good responsiveness.
[0004]
When lowering the steam heating temperature, the temperature of the steam supplied from the steam supply pipe to the heating device is reduced.However, since the high-temperature steam already supplied to the heating device before the reduction is left, the inside of the heating device is reduced. The steam temperature cannot be reduced without time delay, that is, with good responsiveness.
[0005]
The above-mentioned conventional heating device is connected to the combination pump, and the fluid in the heating device is sucked by the combination pump, but remains in the heating device because it is connected through a steam trap on the way. The high-temperature steam cannot be quickly sucked by the combination pump. The function of the steam trap is to pass and discharge only the condensed steam which is condensed without passing and discharging the steam to the downstream side.The steam in the heating device is sucked by the combined pump through the steam trap. You can't.
[0006]
Therefore, an object of the present invention is to provide a steam heating method capable of reducing the steam heating temperature with good responsiveness without causing a time delay when the steam heating temperature is reduced.
[0007]
[Means for Solving the Problems]
Means taken to solve the above problem is to connect a steam supply pipe for supplying steam to the heating device, attach a steam control valve to the steam supply pipe, and control the valve opening of the steam control valve. In addition to a control unit, the heating device is connected to a heating device and a suction unit for sucking a fluid in the device via a suction pipe, and a steam trap and a valve unit are attached to the suction pipe in parallel. When the steam heating temperature is lowered, the valve means is opened for a predetermined time when the steam heating temperature is reduced, and the valve opening of the steam control valve is controlled in accordance with the value detected by the temperature detecting means. .
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
By opening the valve means for a predetermined time when the steam heating temperature is lowered, the heating device and the suction device are connected, the high-temperature steam remaining in the heating device is quickly sucked into the suction device, and the steam heating temperature is reduced by the time. Can be reduced without delay.
[0009]
In addition, when the steam heating temperature is reduced, the temperature of the heating device is controlled by the steam by controlling the valve opening of the steam control valve according to the value detected by the temperature detecting means.
[0010]
【Example】
In the present embodiment, an example in which the reactor 1 is used as a heating device will be described. The object to be heated (not shown) placed in the reactor 1 is heated by steam supplied to the jacket portion 2.
[0011]
A jacket portion 2 is formed over substantially the entire circumference of the reaction vessel 1, and a steam supply pipe 3 is connected above the jacket portion 2 via a steam control valve 4. The suction pipe 5 is connected to the lower end of the jacket 2. An automatic opening / closing valve 6 as a valve means and a steam trap 7 are arranged in the suction pipe 5 in parallel, and connected to a suction section 9 of a suction means 8. The steam trap 7 is an automatic valve that automatically discharges only the condensed water flowing down the suction pipe 5 to the lower outlet side, but does not discharge steam.
[0012]
The suction means 8 includes an ejector 11 including a suction unit 9 having a built-in nozzle and a diffuser 10, a tank 12, and a circulation pump 13. When the circulation pump 13 is driven, fluid such as water in the tank 12 is ejected by the ejector 11. Then, the condensed condensate of the steam in the jacket portion 2 is suctioned by the suction portion 9.
[0013]
A circulating water supply pipe 14 is connected to the upper part of the tank 12, and a circulation path 15 of the suction means 8 is branched to connect a surplus water discharge pipe 16.
[0014]
A pressure sensor 17 for detecting the internal steam pressure and a temperature sensor 18 as temperature detecting means are attached to the jacket 2. Each of the sensors 17, 18, the steam control valve 4, and the automatic on-off valve 6 are electrically connected to a control unit (not shown). The control unit transmits an open / close control signal to the steam control valve 4 and the automatic open / close valve 6 based on the steam pressure value or the temperature value in the jacket portion 2 detected by the sensors 17 and 18.
[0015]
When heating an object to be heated (not shown) in the reaction vessel 1, steam having a temperature or pressure suitable for heating is supplied from the steam supply pipe 3 and the steam control valve 4 to the jacket section 2, so that the steam is supplied to the reaction vessel 1. Heat is given to the object to be heated inside.
[0016]
In the case of saturated steam, the relationship between the steam pressure and the temperature is uniquely determined as shown in FIG. 2, so that the steam temperature can be indirectly controlled by controlling the steam pressure. Usually, when performing steam heating, the steam pressure temperature is controlled by performing steam pressure control using the relationship between the pressure and the temperature.
[0017]
Condensed water generated by condensing steam by heating the object to be heated is drawn from the suction pipe 5 through the steam trap 7 into the suction section 9 of the suction means 8 and reaches the tank 12.
[0018]
The heating temperature is appropriately adjusted by adjusting the steam pressure, that is, the steam temperature, according to the valve opening degree of the steam control valve 4, and by appropriately adjusting the temperature of the fluid flowing down the suction force of the suction means 8 to the ejector 11. For example, the temperature can be set arbitrarily from about 20 ° C. to over 100 ° C.
[0019]
When lowering the steam heating temperature in the jacket portion 2, the steam pressure supplied to the jacket portion 2, that is, the temperature, is reduced by reducing the valve opening of the steam control valve 4 according to a signal from a control unit (not shown). By opening the automatic on-off valve 6 for a predetermined time in response to a signal from the control unit, the high-temperature steam remaining in the jacket portion 2 is quickly sucked into the suction means 8, and the steam heating temperature can be reduced without time delay. Can be reduced.
[0020]
When the steam heating temperature in the jacket portion 2 is reduced, the automatic opening / closing valve 6 is opened for a predetermined time, and the valve opening of the steam control valve 4 is controlled in accordance with the detection value of the temperature sensor 18. The heating device is temperature controlled by steam.
[0021]
By performing the temperature control in place of the pressure control as described above, when the heating temperature is, for example, about 60 ° C. or less, the heating temperature can be controlled more accurately. This is because, as shown in FIG. 2, when the steam temperature is as low as 60 ° C. or less, the rate of change of pressure with respect to a constant rate of change of temperature becomes a very small value. It becomes difficult to detect the change value with the pressure sensor 17, and even if it can be detected, it becomes difficult to control the pressure with the control valve. It is difficult to improve the temperature accuracy.
[0022]
On the other hand, since the rate of change of the temperature is constant whether it is below 60 ° C. or higher, the value does not decrease to detect and control even at a low temperature of 60 ° C. or less. Does not decrease.
[0023]
The time during which the automatic on-off valve 6 is opened depends on the volume of the jacket 2, the steam pressure or temperature in the jacket 2, the type of the automatic on-off valve 6, the effective passage cross-sectional area, or the suction force of the suction means. It can be set appropriately based on the above.
[0024]
【The invention's effect】
In the steam heating method of the present invention, when lowering the steam heating temperature, the valve means between the heating device and the suction means is opened for a predetermined time so that the high-temperature steam remaining in the heating apparatus is quickly sucked into the suction means. Thus, the steam heating temperature can be reduced without time delay.
[0025]
Further, in the steam heating method of the present invention, by controlling the temperature of the heating device after the valve means is opened, the steam heating temperature can be accurately controlled, particularly when the heating temperature is 60 ° C. or lower.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing an embodiment of a steam heating method of the present invention.
FIG. 2 is a relationship diagram showing a relationship between pressure and temperature of saturated steam.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Reactor 2 Jacket part 3 Steam supply pipe 4 Steam control valve 5 Suction pipe 6 Automatic opening / closing valve 7 Steam trap 8 Suction means 17 Pressure sensor 18 Temperature sensor

Claims (1)

A steam supply pipe that supplies steam to the heating device is connected, a steam control valve is attached to the steam supply pipe, and a control unit that controls the valve opening of the steam control valve is provided, and the heating device and the inside of the device are provided. In a heating device connected to a suction means for sucking a fluid through a suction pipe, and a steam trap and a valve means attached to the suction pipe in parallel, a temperature detection means for detecting a temperature of the heating apparatus is attached, and a steam heating temperature is set. A steam heating method comprising: opening the valve means for a predetermined time when the pressure is lowered; and controlling the valve opening of the steam control valve according to the value detected by the temperature detecting means.

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