JPH0784951B2 - Steam supply system - Google Patents

Description

TECHNICAL FIELD The present invention relates to a steam supply system for supplying steam to an indirect heating container to efficiently heat an object to be heated.

<Prior Art> In various manufacturing factories, heat treatment is widely performed. Such heat treatment heats an object to be heated at a high temperature of 100 ° C. or higher or at a low temperature of 100 ° C. or lower. When heating with positive-pressure steam, the high-pressure steam generated in the boiler is depressurized to a desired pressure via a pressure reducing valve and steam of 100 ° C. or higher is supplied to the indirect heating container. Also, when heating with negative pressure steam, a pressure reducing valve is placed on the primary side of the indirect heating container, a vacuum pump is placed on the secondary side, and suction is performed by the pump so that negative pressure is applied after the pressure reducing valve. Generates steam below 100 ℃ and supplies it to the indirect heating container. The pressure reducing valve here is a special pressure reducing valve, and performs the opposite operation of the pressure reducing valve for positive pressure. That is, when the secondary pressure is lower than the set pressure of the pressure reducing valve, the valve opening is opened against the pressure setting spring force to allow the steam to flow to the secondary side.

<Problems to be Solved by the Invention> The advantage of heating with steam in this way is that the enthalpy is larger than that of hot water, so that the heat transfer amount is large, and the heat transfer coefficient is large and heating at a uniform temperature is possible. Because there is. However, in chemical factories and food factories, it may be better not to heat the object to be heated remarkably due to safety of work and product quality. In other words, the above-mentioned advantages of steam are good, but on the other hand, there is a problem that the heating rate is too fast because the heat transmission coefficient is large. Heating with warm water causes uneven heating and is difficult to use.

Therefore, a technical problem of the present invention is to generate and supply steam that has a large heat transfer amount, can be heated at a uniform temperature, and can be softly and softly heated.

<Means for Solving the Problems> In the technical means of the present invention taken to solve the above technical problems, a pressure reducing valve is arranged on the primary side of an indirect heating container and a vacuum pump is arranged on the secondary side. In a system for heat-treating an object to be heated, an air introducing means consisting of a control valve and a temperature sensor is provided between the pressure reducing valve and the indirect heating container, the vacuum pump is connected to the ejector section, the tank, and the cooling water pipe to the tank. It is an ejector type vacuum pump consisting of a pump.

The fact that the introduction of air into the <action> vapor, by Bun'atsunohousoku, such as pressure of the fluid 2Kg / cm ^2, even the partial pressure ratio ratio of steam at 1.5 Kg / cm ^2, air 0.5 Kg / If it is cm ² , the temperature of the fluid will be the saturation temperature of steam of 1.5 kg / cm ² . By changing the air content ratio in this way, an arbitrary steam temperature can be generated.

Moreover, this steam has a small heat transmission coefficient due to the inclusion of air, and can be softly heated.

<Example> An example showing a specific example of the above technical means will be described.
(See FIGS. 1 and 2) The present embodiment is a heating system using negative pressure steam. FIG. 1 is a schematic diagram of an ejector type vacuum pump A used in the apparatus of the present invention. The tank 1 and the pump 2 are connected by a suction pipe 3 and a discharge pipe 4 to which a temperature sensor 10 is attached. The ejector portion 5 is provided in the discharge pipe 4, and the suction port 6 is formed. A cooling water pipe 7 is connected to the tank 1, and an electric valve 8 is provided to interlock with a temperature sensor 10. An electric valve 9 for fluid pressure feeding is provided between the discharge pipe 4 and the ejector unit 5, and the tank 1
It is interlocked with the electrode rod 11 built in.

The fluid in the tank 1 is sucked by the pump 2 from the suction pipe 3 and is pressure-fed to the discharge pipe 4 and the ejector unit 5, and the tank 1 is again fed.
It returns to the inside and circulates. At this time, a suction action is generated in the ejector unit 5, and the pressure thereof is saturated pressure with respect to the temperature of the fluid flowing therein. Therefore, by setting the temperature arbitrarily with the temperature sensor 10 provided in the suction pipe 3, the motor-operated valve 8 is opened and closed to allow the cooling water to enter the tank to maintain a desired fluid temperature, and as a result, the saturated pressure with respect to the set temperature is the ejector portion. It occurs at 5. Therefore, an arbitrary degree of vacuum can be obtained by adjusting the temperature sensor 10.

The vacuum pressure generated in the ejector unit 5 sucks fluid such as condensate or steam from the suction port 6 and pressure-feeds it to the tank 1. When the liquid level in the tank 1 reaches a high water level, the electrode 11 detects it and the electric motor valve 9 for pumping is opened to pump the fluid away. Then, when the predetermined low water level is reached, the motor-operated valve 9 is closed.

FIG. 2 shows a vacuum steam generating and heating device using the ejector type vacuum pump A. The pressure reducing valve 22 is connected to the primary side of the indirect heating container 21 and the vacuum pump A shown in FIG. 1 is connected to the secondary side to reduce the pressure of the system to a negative pressure. The pressure reducing valve 22 is a special pressure reducing valve, and when the pressure in the indirect heating container 21 becomes lower than the set pressure, the valve that has been closed until then starts opening the steam on the primary side into the indirect heating container 21. Supply. If it becomes higher than the desired value, it acts again in the valve closing direction to suppress the supply amount.

A pipe 23 connecting the indirect heating container 21 and the pressure reducing valve 22 is provided with an air introduction pipe 24 and a temperature sensor 26. A control valve 25 is attached to the introduction pipe 24, and based on a signal from the temperature sensor 26, the control pipe 25 is opened and closed so that a desired vapor temperature is reached, and air is introduced. These temperature controls are performed by a controller 27 equipped with set temperature input means.

If the secondary side of the pressure reducing valve 22 is sucked by the vacuum pump A and becomes negative pressure, the introduction pipe 24 is supplied at the same time as the supply of steam from the pressure reducing valve.
Air is introduced from. The temperature of the steam at that time becomes a saturation temperature corresponding to the partial pressure (pressure) of the contained steam, and since the steam contains air, the heat transmission coefficient becomes small.

In this system, the pressure reducing valve 22 is provided, and since the supply pressure of steam is stable, the temperature control by the controller 27 is very easily performed.

Further, as described above, the vacuum pump A can be set to an arbitrary degree of vacuum. Therefore, if the desired value of the pressure in the heating container, that is, the setting value of the pressure reducing valve, is set to the same value, the degree of vacuum in the heating container becomes excessive. It is possible to maintain a constant pressure without

<Effects of the Invention> According to the present invention, a large amount of heat can be conveyed, uniform temperature heating can be performed, and steam capable of being softly and softly heated can be generated and supplied, thereby improving productivity and product quality. Leads to improvement.

[Brief description of drawings]

FIG. 1 is a block diagram of an ejector type vacuum pump used in the apparatus of the present invention, and FIG. 2 is a system diagram of a vacuum vapor generating and heating apparatus of the present invention using the ejector type vacuum pump shown in FIG. . 1: Tank, 2: Pump 5: Ejector part, 10: Temperature sensor 20: Vacuum pump, 21: Indirect heating container 22: Pressure reducing valve, 25: Control valve 26: Temperature sensor, 27: Controller

Claims (1)

[Claims] 1. A system in which a decompression valve is arranged on the primary side of an indirect heating container and a vacuum pump is arranged on the secondary side to heat-process an object to be heated, and a control valve is provided between the decompression valve and the indirect heating container. A vapor supply system characterized in that an air introducing means including a temperature sensor is provided, and the vacuum pump is an ejector type vacuum pump including an ejector section, a tank, cooling water piping to the tank, and a pump.