JP2004016035A - Steam heating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steam heating method in which steam heating temperature can be maintained at a fixed value in high precision. <P>SOLUTION: This steam heating method comprises the following process: joining a steam supply tube 3 to a jacket part 2 of a reactor 1, attaching a steam controlling valve 4 to the steam supply tube 3, attaching a temperature sensor 18 to the jacket part 2, joining a suction means 8 to the lower side of the jacket part 2, and attaching a steam trap 7 and an automatic opening/closing valve 6 to a suction tube 5 in parallel. The steam heating temperature of the jacket part 2 can be maintained at a predetermined value by opening the automatic opening/closing valve 6 to subject the air to suction discharge when the temperature is lowered due to the mixing of air in 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, around 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 in that the temperature during heating cannot be accurately maintained at a constant value. In particular, when the heating is performed at a steam heating temperature of 100 ° C. or less and a vacuum steam pressure of the atmospheric pressure or less, there is a problem that the heating temperature cannot be maintained at a constant value due to air being mixed into the heating device.
[0004]
When heating at a vacuum steam pressure lower than the atmospheric pressure, air is mixed into the heating device from a plurality of hermetic joints of the heating device including various flanges and screws, thereby lowering the heating temperature. . Further, air may be mixed in the supplied heating steam, and in such a case, the heating temperature also decreases.
[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. The air cannot be quickly sucked by the combination pump. The function of the steam trap is to pass and discharge only the condensed steam condensed without passing and discharging the gas such as steam and air to the downstream side, and to remove the air mixed in the heating device through the steam trap. The combination pump cannot eliminate the suction.
[0006]
Accordingly, an object of the present invention is to provide a steam heating method capable of accurately maintaining a constant steam heating temperature at a constant value by quickly removing air mixed into a heating device.
[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. A control unit is provided, and a heating device is connected to a heating device and suction means for sucking fluid in the device via a suction pipe, and a steam trap and a valve means are attached to the suction pipe in parallel. A temperature detecting means for detecting a temperature is attached, and when the temperature detecting means detects a decrease in temperature in the heating device, the valve means is opened for a predetermined time.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
By opening the valve means for a predetermined time when the temperature detecting means detects that the temperature in the heating apparatus has decreased by a predetermined value, the heating apparatus and the suction means are connected, and the air mixed in the heating apparatus is removed. The steam is sucked together with some steam into the suction means, and the steam heating temperature can be maintained at a constant value.
[0009]
【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.
[0010]
A jacket portion 2 is formed over substantially the entire circumference except for the upper portion of the reactor 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 gas such as steam or air.
[0011]
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.
[0012]
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.
[0013]
A pressure sensor 17 for detecting the internal pressure and a temperature sensor 18 for detecting the temperature 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.
[0014]
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.
[0015]
In the case of saturated steam, since the steam pressure and the temperature are uniquely determined, the steam temperature can be indirectly controlled by controlling the steam pressure. That is, by controlling the steam pressure supplied from the steam control valve 4 based on the pressure value detected by the pressure sensor 17, the steam heating temperature can be controlled.
[0016]
When the object to be heated is heated, the steam is deprived of heat and condensed to become condensed water.
[0017]
The heating temperature is adjusted, for example, from about 20 ° C. by appropriately adjusting the set steam pressure at the steam control valve 4, that is, the steam temperature, and appropriately adjusting the temperature of the fluid flowing down to the ejector 11 by the suction force of the suction means 8. The temperature can be arbitrarily set up to a temperature exceeding 100 ° C.
[0018]
When air enters the jacket portion 2 and the temperature in the jacket portion 2 drops, the temperature sensor 18 detects the temperature drop and sends it to a control section (not shown). By transmitting a signal to open the valve only for a certain time, the automatic on-off valve 6 is opened and the air staying in the jacket 2 is sucked into the suction means 8 together with a part of the steam.
[0019]
When a part of the steam is sucked into the suction means 8 together with the air and the steam pressure in the jacket portion 2 becomes lower than the set value, the control section sends a signal from the pressure sensor 17 to the steam control valve 4. A signal for increasing the valve opening is issued, and steam is supplied into the jacket portion 2, so that the inside of the jacket portion 2 is maintained at a predetermined steam pressure, that is, a temperature.
[0020]
The time for opening the automatic opening / closing valve 6 depends on the volume of the jacket portion 2, the steam pressure or temperature in the jacket portion 2, the type of the automatic opening / closing valve 6, the effective passage sectional area, or the suction force of the suction means. It can be set as appropriate based on this.
[0021]
【The invention's effect】
In the steam heating method of the present invention, the heating device is connected to the suction device by detecting that the temperature in the heating device has decreased by a predetermined value by the temperature detecting device and opening the valve device for a predetermined time. The air mixed with the air is sucked together with a part of the steam into the suction means, and the steam heating temperature can be maintained at a constant value.
[Brief description of the drawings]
FIG.
BRIEF DESCRIPTION OF THE DRAWINGS The block diagram which shows the Example of the steam heating method of this invention.
[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 in the heating apparatus is attached, A steam heating method, wherein the valve means is opened for a predetermined time when a temperature decrease in the heating device is detected by the detection means.

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