JPH1019706A - Device for measuring vacuum pressure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for measuring vacuum pressure by which vacuum pressure in a pressure-reduced space can be measured accurately and simply. SOLUTION: This device is provided with a container 1 in which water is filled at a given water level, a heating means 2 which communicates the upper space within the container 1 with a pressure-reduced space subjected to pressure measurement and heats the water in the container 1, a temperature sensor 3 for detecting the temperature of the water in the container 1, and a pressure computing means 4 which computes a pressure according to a relation between previously stored saturation temperature and saturated vapor pressure, based on the detected temperature of a temperatures sensor 3 when the water in the container is heated up to the saturation temperature by the heating means 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring a vacuum pressure in a reduced-pressure space, and is used, for example, in a vacuum deaerator or a vacuum cooling device.

[0002]

2. Description of the Related Art A vacuum deaerator is designed to pass water to be treated through a gas-permeable hollow fiber membrane, to evacuate the outside of the hollow fiber membrane to a reduced pressure state, thereby passing through the membrane wall of the hollow fiber membrane. It is a device that removes dissolved gas in the water to be treated. In the vacuum line of this vacuum deaerator, a strain gauge type sensor is widely used as a sensor for measuring the vacuum pressure. However, since this sensor is expensive and requires calibration, Management was complicated, and it was difficult to maintain accuracy.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a vacuum pressure measuring device capable of accurately and easily measuring a vacuum pressure in a reduced pressure space.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has a container in which water is filled to a predetermined water level, and an upper space in the container is used as a decompression space in which pressure is to be measured. Communicating with a heating means for heating the water in the vessel, comprising a temperature sensor for detecting the temperature of the water in the vessel, wherein the heating means heats the water in the vessel to a saturation temperature; Based on the temperature detected by the sensor,
A first feature is that a pressure calculating means for calculating the pressure from the relationship between the saturated temperature and the saturated steam pressure stored in advance is provided. Further, according to the present invention, when the pressure calculation unit heats the water in the container by the heating unit, the temperature detected by the temperature sensor becomes a constant state, and when the constant state continues for a predetermined time, the water in the container A second feature is to have a function of determining that the saturation temperature has been reached.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION A container filled with water to a predetermined water level is installed, and the upper space of the container is connected to a reduced pressure space in which the pressure is to be measured. The container is provided with heating means such as a heater for heating the water in the container, and a temperature sensor for detecting the temperature of the water in the container. As the temperature sensor, a thermocouple or a thermistor is used. The heating means may be provided inside the container, or may be provided outside the container to heat water in the container from outside.

[0006] The relationship between the saturated temperature and the saturated steam pressure is stored in advance in the pressure calculating means, and when the water in the vessel is heated to the saturated temperature by the heating means, based on the temperature detected by the temperature sensor, The pressure is calculated by the pressure calculating means. The calculated pressure is displayed by appropriate display means.

[0007] Whether the water in the container has reached the saturation temperature is determined based on a change in the temperature of the water. That is, when the water in the container is heated by the heating means, the temperature of the water rises and reaches an equilibrium state when the temperature reaches the saturation temperature. When the equilibrium temperature constant state has continued for a predetermined time, it is determined that the saturation temperature has been reached. After the pressure measurement, the heating means is stopped.

The present invention can be applied to devices having a reduced pressure space, such as a vacuum cooling device and a vacuum drying device, in addition to the vacuum degassing device.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory diagram showing one embodiment of the present invention. A container 1 containing water up to a predetermined water level is provided, and an upper space in the container 1 is communicated with a vacuum line 7 as a reduced pressure space for measuring a pressure. In the illustrated embodiment, the container 1 is connected to the lower part of the vacuum line 7.

The container 1 is provided with a heating means 2 such as a heater for heating the water inside. In the illustrated embodiment,
The heating means 2 is inserted from the lower end of the container 1 and is heated from the inside. However, the heating means 2 is provided so as to cover the side wall of the container 1 and the water in the container 1 is heated from the outside. You can also. The operation / stop of the heating means 2 is controlled by the heating control device 6.

The container 1 is provided with a temperature sensor 3 for detecting the temperature of the water inside. As the temperature sensor 3, a thermocouple, a thermistor, or the like is used, and the temperature sensing portion at the tip is submerged below the water surface.

The relationship between the saturated temperature and the saturated steam pressure is stored in advance in the pressure calculating means 4, and when the water in the vessel 1 is heated to the saturated temperature by the heating means 2, the temperature detected by the temperature sensor 3 is detected. , The pressure is calculated by the pressure calculating means 4. The calculated pressure is displayed by the pressure display means 5.

The operation of the above embodiment will be described. When the water in the container 1 is heated by the heating means 2, the temperature of the water rises and reaches an equilibrium state when it reaches the saturation temperature. Therefore, when the constant temperature state that has reached the equilibrium continues for a predetermined time (for example, 20 seconds), it is determined that the saturation temperature has been reached. The pressure is calculated from the relationship between the temperature and the saturated steam pressure. The calculated pressure is displayed by the pressure display means 5. For example, if the detected temperature is 32.6 ° C., the pressure is 3
8 Torr.

After the pressure measurement, the heating means 2 is stopped in order to suppress water evaporation. In addition, when the amount of water in the container 1 becomes small, the water is appropriately supplied. The amount of water in the container 1 is about 10 cc. Since the saturation temperature is low during the reduced pressure state, the heat capacity of the heating means 2 may be small.

FIG. 2 shows an embodiment in which the present invention is applied to a vacuum deaerator. A degassing module 8 containing a large number of gas-permeable hollow fiber membranes 9 is provided. When water to be treated flows from one end of the hollow fiber membrane 9 to the other end, the outside of the hollow fiber membrane 9 is evacuated. By reducing the pressure, the dissolved gas in the water to be treated is removed through the membrane wall of the hollow fiber membrane 9. As a means for evacuation, a vacuum line 7 having a check valve 10 and a water-sealed vacuum pump 11 inserted therein is connected to the deaeration module 8. A water supply line 12 is connected to the water ring vacuum pump 11.

The vacuum pressure measuring device of the present invention is provided between the check valve 10 and the water-sealed vacuum pump 11 in the vacuum line 7. That is, a container 1 filled with water up to a predetermined water level is provided in communication with the vacuum line 7, and this container 1
A heating means 2 for heating the water in the container and a temperature sensor 3 for detecting the temperature of the water in the container 1 are provided. The pressure sensor 4 is connected to the temperature sensor 3, and when the water in the container 1 reaches the saturation temperature due to the heating of the heating unit 2, the relationship between the previously stored saturation temperature and the saturated steam pressure based on the detected temperature. Calculate the pressure from

The calculated pressure can be displayed by an appropriate display means, or inputted to an operation control device (not shown) of the vacuum deaerator to be used for operation control of the water ring vacuum pump 11. Can also.

Although the water in the container 1 gradually decreases due to evaporation, the water sealed by the water ring vacuum pump 11 is used as makeup water. When the water-sealed vacuum pump 11 is stopped after the vacuum deaeration treatment, the air and the sealed water flow back to the position immediately downstream of the check valve 10, so that the back-flowed sealed water can be supplied to the container 1.

Instead of the water ring type vacuum pump 11, another type of vacuum suction means can be used. Further, the vacuum pressure measuring device of the present invention can be applied not only to a film-type vacuum degassing device but also to a degassing tower type.

[0020]

Since the present invention has the above-described structure, the water in the container is heated to the saturation temperature, and the pressure is determined from the temperature of the water based on the relationship between the saturation temperature and the saturated steam pressure. Thus, the vacuum pressure in the reduced pressure space can be accurately and easily measured. In actual use, calibration is unnecessary, so that management is not complicated, and an inexpensive measuring device can be provided.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the present invention.

FIG. 2 is an explanatory view showing an embodiment in which the present invention is applied to a vacuum deaerator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Container 2 Heating means 3 Temperature sensor 4 Pressure calculating means

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Takuhiro Yamao 7, Horie-cho, Matsuyama-shi, Ehime Prefecture, Miura Kogyo Co., Ltd. Inventor Moto Abe 7-Horiecho, Matsuyama-shi, Ehime Miura Industrial Co., Ltd.

Claims (2)

[Claims] 1. A container 1 containing water up to a predetermined water level,
The upper space in the container 1 communicates with a decompression space in which the pressure is to be measured, a heating means 2 for heating water in the container 1 is provided, and a temperature sensor 3 for detecting the temperature of the water in the container 1 is provided. When the water in the vessel 1 is heated to the saturation temperature by the heating means 2, a pressure calculation is performed based on the temperature detected by the temperature sensor 3 to calculate the pressure from the relationship between the saturation temperature and the saturated steam pressure stored in advance. A vacuum pressure measuring device comprising means 4. 2. The vacuum pressure measuring device according to claim 1, wherein the pressure calculation means 4 keeps the temperature detected by the temperature sensor 3 constant when the water in the container 1 is heated by the heating means 2; A vacuum pressure measuring device having a function of determining that the water in the container 1 has reached a saturation temperature when the constant state continues for a predetermined time.