JP3973064B2 - Deaerator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid deaeration device.
[0002]
[Prior art]
The dissolved gas in the liquid causes corrosion of the pipe, generation of bubbles, a decrease in the heat exchange rate, etc., so degassing is necessary depending on the purpose of use of the liquid. As an example of the degassing device, As shown in FIG. 3, the gas permeable tube 2 ′ is accommodated in a multiple-loop shape in a vacuum chamber-1 ′ having a liquid inlet 121 ′ and an outlet 122 ′ to be degassed at the upper part. Both ends of the tube 2 'are connected to the inflow port 121' and the outflow port 122 ', and the liquid to be treated is gasified while the inside of the chamber 1' is depressurized from the vacuum pulling port 11 'at the upper part of the chamber with a vacuum pump. A system is known in which the gas is circulated through the permeable tube 2 'and the dissolved gas is allowed to permeate into the chamber through the gas permeable tube during this flow. In order to increase the permeation surface area (membrane area) per unit volume of the tube, a small diameter of about several mm is used. Interview - using those focused several 10 to 100 present a drive.
[0003]
[Problems to be solved by the invention]
In the initial stage of the degassing, the amount of dissolved gas in the liquid that has passed through the degassing device is high due to the air trapped in the permeable tube, and until the dissolved gas in the passed liquid settles to a normal value. I need time.
[0004]
However, in the conventional deaeration device described above, it takes a long time to settle down to a normal value (it may reach nearly 1 hour), and it takes a long time to start up.
The reason for this is that it is difficult to evenly pass the liquid through the several tens to 100 parallel fine permeability tubes at the initial stage of the liquid passage, and the air from some of the fine permeability tubes is removed. It is estimated that the main cause is that it takes a long time for the air to completely escape from the entire parallel fine-permeability tube considerably later than other fine-permeability tubes.
[0005]
The objective of this invention is providing the deaeration apparatus which can raise the amount of dissolved gas of a deaeration liquid to a normal value at an early stage.
[0006]
[Means for Solving the Problems]
The degassing apparatus according to the present invention accommodates a plurality of parallel gas permeable tubes in a reduced pressure chamber in a loop shape, and provides a degassed liquid inlet and outlet at the upper portion of the reduced pressure chamber, The other end of the single tube connected to the inlet is connected to one end of the parallel gas permeable tube, the connection portion is located at the inner bottom of the decompression chamber, and the parallel gas permeable tube The other end is connected to the outlet.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an example of a deaeration device according to the present invention.
In FIG. 1, reference numeral 1 denotes a decompression chamber having a vacuum suction port 11, and a degassed liquid inlet gold 121 and an outlet metal fitting 122 are attached to the upper wall. Reference numeral 2 denotes a large number (several 10 to 100) of parallel gas permeable tubes (hereinafter sometimes referred to as a permeable tube bundle), and a coagulant is applied to each end of the bundle by heating and pressing. It is fused and integrated. Reference numeral 3 denotes a single tube connected to the inlet fitting 121. One end of the permeable tube bundle 2 and the single tube 3 are connected by a joint 4, and the joint 4 is connected to the inside of the decompression chamber-1. It is located on the bottom surface. The permeable tube bundle 2 is formed in a multiple loop shape upward from the inner bottom surface of the decompression chamber, and the upper end (the other end) of the permeable tube bundle 2 is connected to the outlet fitting 122. It is.
[0008]
Examples of the gas permeable tube include a polytetrafluoroethylene tube, a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer tube, an ethylene-tetrafluoroethylene copolymer tube, Polychlorotrifluoroethylene tube or the like can be used. The gas permeable tube has an inner diameter of several hundreds μm to several mm, a thickness of several tens of μm to several hundreds of μm, and a parallel number of several tens to several hundreds.
[0009]
Examples of the coagulant include polytetrafluoroethylene powder, tetrafluoroethylene-perfluoroalkylvinyl ether copolymer powder (PFA powder), ethylene-tetrafluoroethylene copolymer powder, and polychlorotrifluoroethylene powder. Etc. can be used.
[0010]
The single tube can be made of the same material as the gas permeable tube, and the cross-sectional area of the single tube can be larger than the cross-sectional area of the permeable tube bundle. preferable.
[0011]
For the decompression chamber, for example, metal (especially stainless steel), glass, plastic, etc. can be used. As the plastic, fluorine such as polytetrafluoroethylene or tetrafluoroethylene-perfluoroalkylvinyl ether copolymer is used. Resins, polypropylene, polyethylene and the like can be exemplified.
[0012]
For the connection between the single tube and the inlet fitting or the connection between the permeable tube and the outlet fitting, for example, as shown in FIG. 2, the fitting 121 is attached to the end of the tube 2 (3). (122) may be connected using a wedge 124 and a cap nut 125, and the metal fitting 121 (122) may be connected to the upper wall of the decompression chamber by a packing 126 and a nut 127. However, this configuration is merely an example, and an appropriate configuration can be obtained as long as a degassed liquid inlet and outlet for a parallel gas permeable tube can be provided in the upper part of the decompression chamber.
[0013]
In the deaeration device according to the present invention, the connection portion 4 between the single tube 3 and the permeable tube bundle 2 is positioned on the bottom surface in the decompression chamber 1, so that the permeation is performed at the initial stage of liquid passage. Even if the head in each permeable tube of the permeable tube bundle 2 is going to be unbalanced, the lowermost end in each permeable tube is communicated in the connecting portion 4 and the head height Therefore, the water head in each permeable tube is flush with the horizontal line, and the liquid flow proceeds, so that the air in each permeable tube is evenly timed. [On the other hand, in the conventional example in which the permeable tube bundle is directly connected to the inlet, each tube of the permeable tube bundle is positioned at the inner bottom surface of the decompression chamber. The vacuum chambers in each tube are separated from each other by a tube partition, and the inner bottom position and the inlet (intercommunication points) Since the water pressure acting resists equal height of water head described above between, it can not be expected rapidity of the].
[0014]
In order to degas the gas dissolved liquid by the degassing apparatus according to the present invention, the inside of the decompression chamber-1 is depressurized by driving a vacuum pump, and the inlet tube 121 passes through the single tube 3 to the permeable tube bundle 2. The liquid is circulated at a predetermined flow rate, and the dissolved gas of the liquid in circulation is permeated and degassed from the tube wall of the permeable tube into the decompression chamber.
The air in the permeable tube bundle 2 is pushed out at the beginning of the flow of the liquid, but as described above, the air can be uniformly extruded from the total permeable tube without imbalance, and a part of the permeability Since the delay of air extrusion from the tube can be eliminated, the amount of dissolved gas flowing out from the outlet 122 is a normal value obtained by subtracting the amount of permeated and degassed gas from the amount of dissolved gas in the inlet influent. In other words, the degassing treatment can be performed quickly by starting up to the true degassed dissolved gas amount that does not contain air in the permeable tube at the beginning of liquid passage.
[0015]
In the rapid deaeration process by the deaeration device according to the present invention, the upstream end of the permeable tube bundle is located at the lowest position of the multi-loop permeable tube bundle, -Based on the fact that the non-uniformity of the liquid flow state in the tube is quickly uniformized by the communication within the permeation tube (short circuit kit) at the lowest point, and in a multi-loop shape. The configuration of the embodiment using the above-mentioned single tube is not limited as long as the communication portion within the permeable tube can be formed at the lowest portion of the permeable tube bundle.
[0016]
【Example】
〔Example〕
130 polytetrafluoroethylene tubes having an inner diameter of 1.0 mm and a thickness of 0.1 mm are focused, and a metal mold is extrapolated to both ends of the tube and PFA powder is used as a coagulant for heating and pressurizing at 370 ° C. for 10 minutes. A gas-permeable tube bundle having a length of 3.0 m by fusing and integrating a heat-shrinkable fluororesin sleeve coated with FPA powder on the inner surface onto the integrated molding end The permeable tube bundle and the polytetrafluoroethylene simple tube are connected with a joint, and an inlet fitting is attached to the end of the single tube, and the outlet tube is attached to the end of the permeable tube bundle. The metal fittings are bound together, and the permeable tube bundle is formed into a multi-loop shape and accommodated in the vacuum chamber together with the single tubes. Each metal fitting is attached to the upper wall of the vacuum chamber, and the single tubes are attached. -Connection joint between the tube and the permeable tube bundle is located on the inner bottom of the vacuum chamber It was.
[0017]
[Comparative Example]
In contrast to the embodiment, the same procedure as in the embodiment was performed, except that a single tube was not used and an inlet fitting was attached to the upstream end of the permeable tube bundle and this fitting was attached to the upper wall of the vacuum chamber.
[0018]
For each of these Examples and Comparative Examples, pure water with a dissolved oxygen amount of 8 ppm was passed at 10 ml / min and a degassing test was performed by reducing the pressure in the vacuum chamber to approximately -720 mmHg. When the time required to reach 1 ppm was measured, it was 32 minutes in the example, but 60 minutes were required in the comparative example.
Therefore, for each of the examples and comparative examples, 200 ml / min of pure water was passed (in order to shorten the test time, the amount of water passed was larger than usual), and the time at which no gas appeared on the outlet side was set. When measured, it was 2 minutes in the example, whereas it was 4 minutes in the comparative example.
[0019]
【The invention's effect】
In the degassing apparatus according to the present invention, as can be confirmed from the above test results, the time for expelling air from the entire permeable tube bundle at the initial stage of liquid passing is short, and as a result, the amount of dissolved gas after degassing is reduced. The normal value can be raised early.
[Brief description of the drawings]
FIG. 1 is a view showing an example of a deaeration device according to the present invention.
FIG. 2 is a view showing an example of a connection structure between a permeable tube bundle and an outlet (single tube and inlet) in the deaeration apparatus according to the present invention.
FIG. 3 is a view showing a conventional deaeration device.
[Explanation of symbols]
1 Vacuum chamber
121 Degassed liquid inlet 122 Degassed liquid outlet 2 Gas permeable tube bundle 3 Single tube 4 Connection joint

Claims (1)

A plurality of parallel gas permeable tubes are housed in a loop in the decompression chamber, a degassed liquid inlet and outlet are provided at the top of the decompression chamber, and one end of the single tube connected to the inlet and the parallel gas permeation are provided. One end of the permeable tube is connected , and the connecting portion is positioned in contact with the bottom surface of the vacuum chamber so that the head height in each permeable tube of the permeable tube at the initial stage of liquid passage becomes equal to quickly. A degassing apparatus characterized in that the other end of the parallel gas permeable tubes is connected to the outlet.

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