Air-liquid separation device

Abstract

To provide a gas-liquid separation device with superior gas-liquid separation capabilities compared to conventional technology. [Solution] The system comprises a raw water storage chamber with a circular cross-section for storing gas-liquid mixed raw water, a raw water supply pipeline connected to the upper part of the raw water storage chamber, a degassed water discharge pipeline connected to the lower part of the raw water storage chamber, a float chamber disposed above the raw water storage chamber and communicating with the raw water storage chamber via a communication hole, and a float valve disposed inside the float chamber which normally keeps the float chamber closed and opens when a predetermined amount of gas accumulates in the float chamber to discharge the gas to the atmosphere. The connection port of the raw water storage chamber to the raw water supply pipeline is directed tangentially to the inner surface of the circumferential wall of the raw water storage chamber, and the communication hole between the raw water storage chamber and the float chamber is shifted from the center of the cross-section of the raw water storage chamber toward the connection port of the raw water supply pipeline.

Description

Technical Field

[0001] The present invention relates to a gas-liquid separation device.

Background Art

[0002] There is disclosed in Patent Document 1 a gas-liquid separation device including a raw water storage chamber having a circular cross-section for storing raw water of gas-liquid mixture, a raw water supply pipe connected to the upper part of the raw water storage chamber, a degassed water discharge pipe connected to the lower part of the raw water storage chamber, a float chamber disposed above the raw water storage chamber and communicating with the raw water storage chamber through a communication hole, and a float valve disposed in the float chamber for normally closing the float chamber and opening by accumulation of a predetermined amount of gas in the float chamber to discharge the gas to the atmosphere side, wherein the connection port of the raw water supply pipe of the raw water storage chamber is directed in the tangential direction of the inner surface of the peripheral side wall of the raw water storage chamber, and the communication hole between the raw water storage chamber and the float chamber is positioned at the center of the cross-section of the raw water storage chamber. In the above gas-liquid separation device, when the water level in the float chamber rises and the float rises, the float valve closes, and when the water level in the float chamber drops and the float drops, the float valve opens. The water level in the float chamber increases or decreases according to the magnitude of the flow rate of the raw water of gas-liquid mixture flowing into the raw water storage chamber. When the above gas-liquid separation device operates, the raw water flowing from the raw water supply pipe into the raw water storage chamber flows in the tangential direction of the inner surface of the peripheral side wall of the raw water storage chamber to form a swirling flow, and the bubbles dispersed in the raw water gather at the central part of the cross-section of the raw water storage chamber by the centrifugal separation action of the swirling flow to form a bubble group. The bubble group rises in the raw water, flows into the float chamber from the communication hole, gas accumulates in the float chamber, the water level in the float chamber drops, the float drops, the float valve opens, and the gas separated from the raw water is discharged to the atmosphere side.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As a result of diligent research, the inventors of this application discovered, as can be seen in Figure 1, that when the bubble cluster rises in the center of the cross-section of the raw water storage chamber, it is drawn toward the connection port of the raw water storage chamber to the raw water supply pipeline. It is believed that the ejector effect of the raw water flowing into the raw water storage chamber draws the raw water above the connection port of the raw water storage chamber toward the connection port, and that the bubble cluster rising in the raw water is carried toward this raw water. In light of the above findings, in the gas-liquid separation device of Patent Document 1, since the communication hole between the float chamber and the raw water storage chamber is located at the center of the cross-section of the raw water storage chamber, the group of bubbles that rise towards the connection port of the raw water supply pipeline in the raw water storage chamber cannot be guided to the communication hole. As a result, the group of bubbles cannot be effectively introduced into the float chamber, gas cannot be effectively accumulated in the float chamber, and consequently, the gas separation function may not be effectively performed. The present invention has been made in view of the above problems, and aims to provide a gas-liquid separation device that has superior gas-liquid separation capabilities compared to the prior art, comprising: a raw water storage chamber with a circular cross-section for storing gas-liquid mixed raw water; a raw water supply pipeline connected to the upper part of the raw water storage chamber; a degassed water discharge pipeline connected to the lower part of the raw water storage chamber; a float chamber disposed above the raw water storage chamber and communicating with the raw water storage chamber through a communication hole; and a float valve disposed inside the float chamber, which normally keeps the float chamber closed and opens when a predetermined amount of gas accumulates in the float chamber to discharge the gas to the atmosphere, wherein the connection port of the raw water storage chamber to the raw water supply pipeline is directed tangentially to the inner surface of the circumferential wall of the raw water storage chamber. [Means for solving the problem]

[0005] To solve the above problems, the present invention provides a gas-liquid separation device comprising: a raw water storage chamber with a circular cross-section for storing gas-liquid mixed raw water; a raw water supply pipeline connected to the upper part of the raw water storage chamber; a degassed water discharge pipeline connected to the lower part of the raw water storage chamber; a float chamber disposed above the raw water storage chamber and communicating with the raw water storage chamber via a communication hole; and a float valve disposed inside the float chamber, which normally keeps the float chamber closed and opens when a predetermined amount of gas accumulates in the float chamber to discharge the gas to the atmosphere, wherein the connection port of the raw water storage chamber to the raw water supply pipeline is directed tangentially to the inner surface of the circumferential side wall of the raw water storage chamber, and the communication hole between the raw water storage chamber and the float chamber is shifted from the center of the cross-section of the raw water storage chamber toward the connection port of the raw water supply pipeline. In this invention, the communication hole between the raw water storage chamber and the float chamber is offset from the center of the raw water storage chamber's cross-section toward the connection port to the raw water supply pipeline. As a result, the group of bubbles rising in the raw water while being offset toward the connection port to the raw water supply pipeline can be guided to the communication hole and effectively introduced into the float chamber, allowing for effective accumulation of gas in the float chamber, effectively opening the float valve, suppressing water leakage from the float valve, and effectively discharging the gas separated from the raw water to the outside air.

[0006] In a preferred embodiment of the present invention, longitudinally extending float guide protrusions are dispersed at intervals in the circumferential direction on the inner surface of the circumferential side wall of the float chamber. The placement of float guide protrusions allows for smoother float movement and improves gas discharge functionality. In a preferred embodiment of the present invention, the shape of the communication hole between the raw water storage chamber and the float chamber is rectangular. By making the shape of the communication hole rectangular, the gas discharge function is improved compared to when the shape of the communication hole is circular. In a preferred embodiment of the present invention, the edge line of the communication hole between the raw water storage chamber and the float chamber that is close to and facing the inner surface of the circumferential side wall of the float chamber is an arc. By making the edge line of the communication hole between the raw water storage chamber and the float chamber, which is close to and facing the inner surface of the side wall of the float chamber, an arc is formed, the gas discharge function is improved compared to when the edge line is a straight line. In a preferred embodiment of the present invention, the arc-shaped edge line of the communication hole between the raw water storage chamber and the float chamber, which is close to and facing the inner surface of the circumferential side wall of the float chamber, does not come into contact with the inner surface of the circumferential side wall of the float chamber. When the edge of the communication hole between the raw water storage chamber and the float chamber, which is close to and facing the inner surface of the side wall of the float chamber, comes into contact with the inner surface of the side wall of the float chamber, the gas discharge function deteriorates. In a preferred embodiment of the present invention, the ratio of the area of ​​the communication hole between the raw water storage chamber and the float chamber to the inner diameter area of ​​the upper part of the raw water storage chamber, i.e., the area of ​​the communication hole / the inner diameter area of ​​the upper part of the raw water storage chamber, is 6.5% to 12.7%. By setting the ratio of the area of ​​the communication hole between the raw water storage chamber and the float chamber to the inner diameter area of ​​the upper part of the raw water storage chamber, i.e., the area of ​​the communication hole / the inner diameter area of ​​the upper part of the raw water storage chamber, to 6.5% to 12.7%, good leak prevention and gas discharge functions can be obtained. [Brief explanation of the drawing]

[0007] [Figure 1] These are photographs showing the operation of a conventional gas-liquid separation device made of transparent material. (a) is a photograph of the overall appearance of the device, and (b) is a photograph focusing on the bubbles. [Figure 2] This is a structural diagram of a gas-liquid separation apparatus according to an embodiment of the present invention. (a) is a front view, (b) is a view taken along arrow bb in (a), (c) is a cross-sectional view taken along the cutting line cc in (a), (d) is a view taken along arrow dd in (a), and (e) is a view taken along arrow ee in (a). [Figure 3] This is a block diagram of the test apparatus for the gas emission rate verification test. [Figure 4] This is a top view of the bottom wall of the float chamber of a gas-liquid separation device. (a) shows the structure of the conventional product, and (b) to (l) show the structure of the improved product. [Modes for carrying out the invention]

[0008] A gas-liquid separation apparatus according to an embodiment of the present invention is described below. As shown in Figure 2, the gas-liquid separation device 1 comprises a raw water storage chamber 2 with a circular cross-section for storing raw water mixed with gas, a raw water supply pipeline 3 connected to the upper part of the raw water storage chamber 2, a degassed water discharge pipeline 4 connected to the lower part of the raw water storage chamber 2, a float chamber 5 disposed above the raw water storage chamber 2 and communicating with the raw water storage chamber through a communication hole 5a, and a float valve 6 having a float 6a and a valve mechanism 6b, disposed inside the float chamber 5, which normally closes the float chamber 5 and opens when a predetermined amount of gas accumulates in the float chamber 5 to discharge the gas to the atmosphere. The connection port 2a of the raw water storage chamber 2 to the raw water supply pipeline 3 is directed tangentially to the inner surface of the side wall surrounding the raw water storage chamber 2, and the connection port 2b of the raw water storage chamber 2 to the deaerated water discharge pipeline 4 is directed tangentially to the inner surface of the side wall surrounding the raw water storage chamber 2. The communication hole 5a between the raw water storage chamber 2 and the float chamber 5 is offset from the center C of the cross-section of the raw water storage chamber towards the connection port 2a of the raw water storage chamber 2 to the raw water supply pipeline 3.

[0009] The operation of the gas-liquid separation device 1 will be explained. As shown in Figures 2(c) to 2(e), the raw water flowing from the raw water supply pipeline 3 into the raw water storage chamber 2 flows tangentially to the inner surface of the circumferential side wall of the raw water storage chamber 2, forming a swirling flow SF. The bubbles dispersed in the raw water gather near the center of the raw water storage chamber cross-section due to the centrifugal force of the swirling flow SF, forming a bubble cluster. As shown by the white arrow A1 in Figure 2(c), the bubble cluster rises in the raw water near the center of the raw water storage chamber cross-section. Due to the ejector effect of the raw water flowing from the raw water supply pipeline 3 into the raw water storage chamber 2, the raw water above the connection port 2a between the raw water storage chamber 2 and the raw water supply pipeline 3 is drawn towards the connection port 2a. This raw water carries the group of bubbles rising in the raw water near the center of the raw water storage chamber's cross-section, causing the upward flow of the bubble group to be directed towards the connection port 2a, as shown by the white arrow A2 in Figure 2(c). Since the communication hole 5a between the raw water storage chamber 2 and the float chamber 5 is offset from the center C of the raw water storage chamber cross-section toward the connection port 2a of the raw water storage chamber 2 to the raw water supply pipeline 3, the rising bubbles that are offset toward the connection port 2a accumulate directly below the communication hole 5a and enter the float chamber 5 through the communication hole 5a. The gas accumulated in the float chamber 5 pushes down the water level in the float chamber 5, causing the float 6a to descend. When the amount of gas accumulated in the float chamber 5 reaches a predetermined value, the float valve 6 opens due to the operation of the valve mechanism 6b, and the gas is discharged into the outside air. As can be seen from the above explanation, in the gas-liquid separation device 1, the communication hole 5a between the raw water storage chamber 2 and the float chamber 5 is shifted from the center C of the cross-section of the raw water storage chamber toward the connection port 2a of the raw water storage chamber 2 with the raw water supply pipeline 3. Therefore, the group of bubbles rising in the raw water is guided to the communication hole 5a, effectively introducing the group of bubbles into the float chamber 5, effectively accumulating gas in the float chamber 5, effectively opening the float valve 6, suppressing water leakage from the float valve 6, and effectively discharging the gas separated from the raw water to the outside air.

[0010] If the communication hole 5a is too small, the inflow of gas into the float chamber 5 is restricted, reducing the amount of gas discharged. On the other hand, if the communication hole 5a is too large, the float 6a becomes unstable due to the turbulence of the raw water in the raw water storage chamber 2, causing the operation of the float valve 6 to become unstable, the closed float valve 6 to open, and the raw water to leak out through the float valve 6. Therefore, in order to select the optimal communication hole 5a that balances gas discharge efficiency and leakage prevention, several gas-liquid separation devices 1 with different areas, positions, and shapes of communication holes 5a were prototyped, and the gas discharge efficiency and the maximum raw water flow rate at which leakage could be prevented were measured. The test conditions were as follows.

[0011] 1. Leakage confirmation test (1) Test method Water was supplied to the raw water inlet pipeline 3 of the prototype gas-liquid separator 1 for 150 seconds at a predetermined water pressure and varying flow rates, and the water flow rate at the time of leakage from the float valve 6 was measured. (2) Test conditions (a) Applied water pressure: 300 kPa (considering that the maximum value of the internal pressure of the circulation path connecting the heat source unit having a heat pump of a storage water heater and the storage unit having a storage tank where the gas-liquid separation device 1 is expected to be used is expected to be less than 300 kPa) (b) Water flow rate: Gradually increase the water flow rate from 45 L / min to 70 L / min in 5 L / min increments, and detect the presence or absence of water leakage at each water flow rate. (Considering that the hot water flow rate of the above-mentioned circulation path is 50 - 65 L / min) (c) Judgment criterion: The maximum water flow rate at which water leakage can be prevented (hereinafter referred to as the allowable water flow rate) is 65 L / min or more. (Considering that the maximum value of the hot water flow rate of the above-mentioned circulation path is 65 L / min)

[0012] 2. Gas discharge rate confirmation test (1) Test device The block diagram of the test device is shown in Figure 3. (2) Test method Supply gas-liquid mixed water to the raw water introduction pipeline 3 of the gas-liquid separation device 1 of the prototype at a predetermined water pressure, water flow rate, and air inflow rate, measure the flow rate of the air discharged from the float valve 6, and measure the air discharge rate (air discharge flow rate / air inflow rate). (3) Test conditions (a) Gas used: Air (b) Applied water pressure: 300 kPa (c) Water flow rate: 50 L / min (d) Air inflow rate: 30 NL / min (considering that the maximum flow rate of the refrigerant gas that may be mixed into the hot water of the above-mentioned circulation path is expected to be less than 30 NL / min) (e) Judgment criterion: The air discharge rate is 90% or more.

[0013] 3. Test results[[ID=​​The ratio of the area of ​​the connecting hole to the area of ​​the inner diameter part above the raw water storage chamber in a conventional gas-liquid separator installed in the circulation path of a heat pump type hot water heater (the structure is the same as gas-liquid separator 1, but the circular connecting hole between the raw water storage chamber and the float chamber is positioned at the center of the cross-section of the raw water storage chamber. More specifically, the center, which is the area centroid of the circular connecting hole, is positioned at the center of the cross-section of the raw water storage chamber), i.e., the area of ​​the connecting hole / the area of ​​the inner diameter part above the raw water storage chamber (in the following text, the connecting hole area / Considering that the through-hole area ratio is approximately 12%, a prototype of a conventional product (Figure 4(a)) was manufactured with the communication hole 5a of the gas-liquid separator 1 positioned at the center C of the raw water storage chamber cross-section and the communication hole area ratio set to 12% (circular hole with a diameter of 20 mm). A leak test was conducted, and the allowable water flow rate was 45 L / min, which did not reach the lower limit of 50 L / min for the hot water flow rate in the circulation path of the heat pump type storage water heater in which the gas-liquid separator 1 is planned to be used. Therefore, an improved product 1 (Figure 4(b)) was manufactured with the communication hole positioned at the center of the raw water storage chamber cross-section and the communication hole area ratio set to 8.7% (circular hole with a diameter of 17 mm). A leak test was conducted, and the allowable water flow rate increased to 55 L / min, which fell within the hot water flow rate range of 50-65 L / min for the heat pump type storage water heater in which the gas-liquid separator 1 is planned to be used.

[0014] (2) Leakage Improvement and Gas Emission Rate Improvement Test 1 Taking into account the results of the water leakage confirmation test, in order to improve product 1 (Figure 4(b)) based on the present invention, the area ratio of the communication holes was fixed at 8.7% (circular holes with a diameter of 17 mm), and improved product 2 (Figure 4(c)) was created by shifting the position of the communication holes 3 mm from the center C of the raw water storage chamber cross-section toward the connection port 2a between the raw water storage chamber 2 and the raw water flow pipeline 3. Improved product 3 (Figure 4(d)) was created by shifting the position of the communication holes 10 mm from the center C of the raw water storage chamber cross-section toward the connection port 2a between the raw water storage chamber 2 and the raw water flow pipeline 3. The allowable water flow rate and air discharge rate were measured for each prototype. As a result, improved product 1 had an allowable water flow rate of 55 L / min and an air emission rate of 62.9%, improved product 2 had an allowable water flow rate of 60 L / min and an air emission rate of 65.2%, and improved product 3 had an allowable water flow rate of 65 L / min and an air emission rate of 68.5%. Furthermore, in order to make the movement of the float 6a smoother, an improved product 4 (Figure 4(e)) was prototyped in which the float guide protrusions 5b extending in the longitudinal direction on the inner surface of the circumferential side wall of the float chamber 5 of improved product 3 were distributed at equal intervals in the circumferential direction. The allowable water flow rate and air discharge rate were measured, and the results showed that compared to improved product 3, the allowable water flow rate was maintained at 65 L / min and the air discharge rate increased to 73.4%.

[0015] (3) Leakage Improvement and Discharge Rate Improvement Test 2 Taking into account the results of Leakage Improvement and Discharge Rate Improvement Test 1, in order to further improve product 4 (Figure 4(e)), the distributed arrangement of float guide protrusions 5b on the inner surface of the side wall surrounding the float chamber was fixed, and the position of the communication hole 5a was shifted 10 mm from the center C of the raw water storage chamber cross-section toward the connection port 2a between the raw water storage chamber 2 and the raw water flow pipeline 3, and the area ratio of the communication hole was increased to 9.8% (circular hole with a hole diameter of 18 mm). We prototyped product 5 (Figure 4(f)), improved product 6 (Figure 4(g)) which has a communication hole area ratio of approximately the same as improved product 5 at 10%, a communication hole position (area centroid position) approximately the same as improved product 5, and a communication hole shape approximately square, and improved product 7 (Figure 4(h)) which has a communication hole area ratio of 9.9% in which the edge line facing the inner surface of the side wall of the float chamber of improved product 6 is changed from a straight line to a circular arc, and measured the allowable water flow rate and air discharge rate of each product. As a result, compared to improved product 4, the allowable water flow rate was maintained at 65 L / min for improved products 5, 6, and 7, while the air emission rate increased to 85.4% for improved product 5 and to 95.0% for improved products 6 and 7. Furthermore, 3D-CAD fluid analysis conducted in parallel with the leak improvement and discharge rate improvement test 2 revealed that the water flow velocity in the raw water storage chamber 2 at the communication hole location was slower in improved product 6 compared to improved product 5, and that the water flow velocity at the communication hole location was slower in improved product 7 compared to improved product 6. It is thought that a slower water flow velocity makes it easier for groups of bubbles to enter the float chamber through the communication hole. Therefore, the fluid analysis confirmed that improved product 6 is superior to improved product 5 from the viewpoint of improving the gas discharge rate, and improved product 7 is superior to improved product 6. Furthermore, the fluid analysis described above revealed that when the arc-shaped edge of the improved product 7 contacts the inner surface of the circumferential side wall of the float chamber, the water flow velocity at the communication hole increases. It is thought that a high water flow velocity makes it difficult for groups of bubbles passing through the communication hole to enter the float chamber. Therefore, from the viewpoint of improving the gas discharge rate, it is desirable that the arc-shaped edge of the communication hole does not contact the inner surface of the circumferential side wall of the float chamber.

[0016] (4) Leakage Improvement and Discharge Rate Improvement Test 3 Taking into account the results of Leakage Improvement and Discharge Rate Improvement Test 2, in order to further improve product 7 (Figure 4(h)), several prototypes were manufactured: improved product 7-A (Figure 4(i)) with the same communication hole position and shape as improved product 7 but with the communication hole area ratio reduced to 6.1%, improved product 7-B (Figure 4(j)) with the communication hole area ratio reduced to 6.5%, improved product 7-C (Figure 4(k)) with the communication hole area ratio increased to 12.7%, and improved product 7-D (Figure 4(l)) with the communication hole area ratio increased to 13.3%, while retaining the same communication hole position and shape as improved product 7; improved product 7-B (Figure 4(j)) with the communication hole area ratio reduced to 6.5%, improved product 7-C (Figure 4(k)) with the communication hole area ratio increased to 12.7%, and improved product 7-D (Figure 4(l)) with the communication hole area ratio increased to 13.3%. The allowable water flow rate and air discharge rate were measured for each prototype. As a result, compared to improved product 7, improved product 7-A increased the allowable water flow rate to 70 L / min but decreased the air emission rate to 84.7%, improved product 7-B increased the allowable water flow rate to 70 L / min but decreased the air emission rate to 90.0%, improved product 7-C maintained the allowable water flow rate at 65 L / min and the air emission rate at 95.0%, and improved product 7-D decreased the allowable water flow rate to 60 L / min and maintained the air emission rate at 95.0%. From Leakage Improvement and Discharge Rate Improvement Test 3, it was found that improved products 7, 7-B, and 7-C met the criteria for both the air discharge efficiency confirmation test and the leak confirmation test, demonstrating that they achieved both gas discharge efficiency and leak elimination. [Industrial applicability]

[0017] This invention is widely applicable to gas-liquid separation devices. [Explanation of Symbols]

[0018] 1 Gas-liquid separator 2. Raw Water Storage Chamber 2a Connection point between the raw water storage chamber and the raw water supply pipeline 2b Connection port between the raw water storage chamber and the deaerated water discharge pipeline. 3 Raw water supply pipeline 4 Deaerated water discharge pipe 5. Float chamber 5a Communication hole 5b Float guide protrusion 6. Float valve 6a Float 6b Valve mechanism A1, A2 Bubble Flow C Center of the raw water storage chamber cross-section SF swirl flow

Claims

1. A gas-liquid separation device comprising: a raw water storage chamber with a circular cross-section for storing gas-liquid mixed raw water; a raw water supply pipeline connected to the upper part of the raw water storage chamber; a degassed water discharge pipeline connected to the lower part of the raw water storage chamber; a float chamber disposed above the raw water storage chamber and communicating with the raw water storage chamber via a communication hole; and a float valve disposed inside the float chamber, which normally keeps the float chamber closed and opens when a predetermined amount of gas accumulates in the float chamber to discharge the gas to the atmosphere, wherein the connection port of the raw water storage chamber to the raw water supply pipeline is directed tangentially to the inner surface of the circumferential side wall of the raw water storage chamber, and the communication hole between the raw water storage chamber and the float chamber is offset from the center of the cross-section of the raw water storage chamber toward the connection port of the raw water supply pipeline.

2. The gas-liquid separation apparatus according to claim 1, characterized in that float guide protrusions extending in the longitudinal direction are dispersed at intervals in the circumferential direction on the inner surface of the circumferential side wall of the float chamber.

3. The gas-liquid separation apparatus according to claim 1, characterized in that the shape of the communication hole between the raw water storage chamber and the float chamber is rectangular.

4. The gas-liquid separation apparatus according to claim 3, characterized in that the edge line of the communication hole between the raw water storage chamber and the float chamber, which is close to and facing the inner surface of the circumferential side wall of the float chamber, is an arc.

5. The gas-liquid separation apparatus according to claim 4, characterized in that the arc-shaped edge line of the communication hole between the raw water storage chamber and the float chamber, which is close to and facing the inner surface of the circumferential side wall of the float chamber, does not come into contact with the inner surface of the circumferential side wall of the float chamber.

6. The gas-liquid separation apparatus according to claim 5, characterized in that the ratio of the area of ​​the communication hole between the raw water storage chamber and the float chamber to the inner diameter area of ​​the upper part of the raw water storage chamber, i.e., the area of ​​the communication hole / the inner diameter area of ​​the upper part of the raw water storage chamber, is 6.5% to 12.7%.

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