JP4894072B2 - Line cleaning method and apparatus - Google Patents

Description

  The present invention relates to a line cleaning method and apparatus capable of performing stationary cleaning.

  In food factories, beverage factories, etc., production facilities and equipment are washed when production varieties are switched or when operations are completed. In particular, pipes, tanks, etc. (lines), which are manufacturing facilities and equipment, cannot be disassembled and cleaned, so CIP (fixed cleaning) is performed. CIP is an abbreviation for “Cleaning In Place” and is a method of cleaning by flowing a cleaning agent without disassembling the line.

  A device (CIP device) that performs this CIP includes a cleaning agent tank, a heating device, an automatic switching valve for a detergent, and the like. And in order to wash | clean the line which was flowing the product, the CIP apparatus is flowing so that a washing | cleaning agent may be filled for a washing | cleaning and a cleansing water may be filled for a rinse. A general method for performing CIP of a line is performed by the following procedure. After the production of the product is completed, the inside of the line is first pre-washed with water to reduce the residue of the product. Thereafter, an alkaline detergent is poured into the line to dissolve and remove proteins and carbohydrates. Next, clean water for rinsing is poured into the line as an intermediate rinse to prevent the cleaning agent used in the first cleaning step from being mixed into the cleaning agent used in the next step. After this, an acid cleaning agent is flowed through the line to remove inorganic deposits. Finally, clean water is allowed to flow through the line as an acid cleaning agent rinse, and the CIP is terminated. After this, sodium hypochlorite may be sterilized and rinsed through the line. In addition, in the CIP process, a gas pipe may be installed in the CIP apparatus or the line for the purpose of removing the cleaning agent and fresh water in each step, thinning the cleaning agent, and collecting the first product.

  In order to improve the performance of such CIP, measures such as increasing the concentration of the cleaning agent, raising the temperature by heating the cleaning agent, and increasing the circulation flow rate can be taken. However, these methods have a problem of increasing costs.

The deodorizing and cleaning method disclosed in Patent Document 1 introduces gas into the piping line to generate a gas-liquid two-phase flow of gas and liquid when deodorizing and cleaning the inner surface of the pipe line by CIP, This is applied to the target site for CIP and deodorization. In this deodorizing and cleaning method, the flavor component is transferred from the inside of the packing to the bubbles using the vapor pressure of the flavor component penetrating into the packing.
JP 2006-181450 (pages 3-4 and 8-9)

  The deodorizing and cleaning method of Patent Document 1 described above evaporates the flavor component. Therefore, increasing the surface area of the bubbles (decreasing the bubble diameter) is considered effective for deodorizing and cleaning. However, when removing deposits (various deposits such as proteins and carbohydrates) adhering to the line, it is necessary to increase the bubble diameter and fluctuate the pressure to separate. Therefore, when removing the product adhering to the line, the invention described in Patent Document 1 may not be able to expect a sufficient effect.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a line cleaning method and apparatus that improves the cleaning performance of the line and shortens the cleaning time.

The line cleaning method according to the present invention supplies gas to the inside of the line from a plurality of gas pipes connected from the upstream side to the downstream side of the line, and supplies a cleaning liquid to the inside of the line. A line cleaning method for generating a phase flow and stationary cleaning the inside of the line, and when connecting a plurality of the gas pipes from the upstream side to the downstream side of the line, the gas is supplied from the gas pipes on the upstream side. A gas-liquid two-phase flow obtained by supplying the gas pipe into the line by connecting the gas pipe on the downstream side with respect to the upstream side of the location where the gas-liquid two-phase flow becomes an upper and lower two-phase flow, and the inflow of the gas into the line The inside of the line is washed by changing the amount . In this case, the gas can be intermittently flowed into the line, and the inside of the line can be cleaned alternately by the gas-liquid two-phase flow and the cleaning liquid . Further, among the gas pipe connected to the upstream side of the line and the gas pipe connected to the downstream side, gas is constantly supplied from one of the gas pipes, and gas is supplied intermittently from the other gas pipe. You can also. Further, the size of the bubbles constituting the gas-liquid two-phase flow can be changed by changing the pressure of the gas supplied from the gas pipe . In this case, the gas pressure can be periodically changed. Furthermore, a means for mixing a fluid flowing inside the line is provided between the gas pipe connected to the upstream side of the line and the gas pipe connected to the downstream side so as to generate a gas-liquid two-phase flow. Anyway.

The line cleaning apparatus according to the present invention is a line cleaning apparatus that performs stationary cleaning of the inside of a line, the means for supplying a cleaning liquid to the line, the gas to the line, and the interior of the line A first gas pipe that obtains a gas-liquid two-phase flow of the cleaning liquid and the gas, and the gas-liquid two-phase flow is an upper and lower two-phase flow downstream of the line from the connection point of the first gas pipe. A gas is supplied to the line on the upstream side of the portion, a second gas pipe that obtains a gas-liquid two-phase flow of the cleaning liquid and the gas inside the line, the first gas pipe, and the a downstream of said line than point where the line connecting the second gas pipe and the line than locations is connected is provided on an upstream side of the line, the fluid flowing inside the said line and means for mixing comprises, Serial wherein the first gas pipe second gas pipe is characterized in that varying the flow rate of gas into the line.

  According to the line cleaning method of a CIP device that automatically cleans a line, a gas-liquid two-phase flow can be obtained by adding gas to the cleaning liquid flowing in the line, and the line is formed using this gas-liquid two-phase flow. Washing can improve cleanability and shorten washing time. Also, when CIP is performed using a gas-liquid two-phase flow, if the gas supply amount is changed, a change in the flow of the gas-liquid two-phase flow can be caused. , Can improve the cleaning performance. Further, if gas is intermittently supplied to the line, it is possible to prevent gas accumulation in the line, so that it is possible to prevent a portion that is not cleaned from occurring.

  Further, if gas is supplied to the line from a plurality of locations, a change occurs in the flow of the gas-liquid two-phase flow, so that the cleaning of the inner surface of the line can be promoted and the cleaning time can be reduced. Therefore, the line can be reliably cleaned. Furthermore, if the pressure of the gas supplied from the gas pipe to the line is changed, the size of the bubbles constituting the gas-liquid two-phase flow can be changed. As a result, it is possible to change the portion where the cleaning effect of the line is high, and the line can be cleaned in a wide range. In addition, when the gas pressure is periodically changed, the wide range of the line can be cleaned uniformly.

  Also, if a line cleaning device that automatically cleans the line is used, the fluid flowing through the line can be mixed, so that the gas-liquid two-phase flow obtained with the cleaning liquid and the gas is separated into the cleaning liquid and the gas. Can be prevented.

Hereinafter, embodiments of a line cleaning method and apparatus according to the present invention will be described. First , an embodiment related to the present invention will be described. FIG. 1 is a schematic system diagram of a product production line equipped with a line cleaning device. The product production line 10 includes a product tank 14 for heating and mixing and reacting the product 12, a product pump 16 for sending the product 12 to the subsequent stage, a device for processing the product 12 (processing device 18), and a product. The first valve 20 disposed between the tank 14 and the product pump 16, the second valve 22 disposed between the processing equipment 18 and the next process, and these are connected and the product 12 is supplied to the next process. A product supply pipe 24 is provided.

  The line cleaning device 30 for performing CIP of the product manufacturing line 10 includes a CIP device 31, and a cleaning agent tank 32 for individually storing an alkaline cleaning agent, an acid cleaning agent, fresh water, and the like inside the CIP device 31. I have. The outlet side of the cleaning agent tank 32 is connected to a product supply pipe 24 between the first valve 20 and the product pump 16 via a liquid supply pipe 34. A liquid feed pump 36 is disposed in the liquid feed pipe 34, and a third valve 38 is disposed downstream of the liquid feed pump 36. Further, a first gas pipe 40 is connected to the liquid feed pipe 34 after the third valve 38. The first gas pipe 40 supplies gas to the liquid feed pipe 34, and collects the product 12, the alkaline cleaner, and the acid cleaner when performing CIP, and also performs the gas-liquid two-phase flow. Provided to get. The liquid supply pipe 34 branches between the liquid supply pump 36 and the third valve 38, and the end of the liquid supply pipe 34 is connected to the sprayer 44 disposed in the product tank 14 via the fourth valve 42. is doing. The CIP device 31, the liquid feed pump 36, the liquid feed pipe 34, and the like serve as means for supplying the cleaning liquid.

  Further, the line cleaning device 30 has a drainage pipe 46, one end of which is connected to the product supply pipe 24 between the processing device 18 and the second valve 22. A fifth valve 48 is disposed on the inlet side of the drainage pipe 46, that is, in the vicinity of a portion connected to the product supply pipe 24. The drainage pipe 46 is branched halfway, one after this branch is connected to the CIP device 31 via the sixth valve 50, and the other is connected to the drainage device via the seventh valve 52. Yes.

  In the product production line 10 equipped with such a line cleaning device 30, when producing the product 12, the product 12 is first heated and mixed and reacted in the product tank 14. Thereafter, the first valve 20 is opened and the product pump 16 is operated to send the product 12 from the product tank 14 to the processing device 18 through the product supply pipe 24. At this time, the third valve 38 is closed. When the processing of the product 12 is completed by the processing device 18, the second valve 22 is opened, and the product 12 is sent to the next process via the product supply pipe 24. At this time, the first valve 20 and the second valve 22 are opened, and the third valve 38 and the fifth valve 48 are closed.

  When the production of the product 12 is completed by such a process, CIP is performed using the line cleaning device 30 until the next production starts. Prior to this CIP, first, a gas such as air is caused to flow from the first gas pipe 40 to the liquid feed pipe 34 in order to collect the product 12 in the product production line 10. At this time, since the third valve 38 is closed, the gas is sent to the product supply pipe 24. As a result, the product 12 remaining in the product supply pipe 24 or the like is sent to the next process or the like by gas, and the product 12 is collected. After the product 12 is collected, the inflow of air from the first gas pipe 40 is stopped.

  The line cleaning method is as follows. First, clean water (cleaning liquid) is supplied from the CIP device 31 for rough cleaning. That is, the fourth valve 42 is opened and the third valve 38 is closed, and the liquid feed pump 36 is operated. Then, fresh water is sent from the cleaning agent tank 32 to the sprayer 44 in the product tank 14, and the fresh water flows from the sprayer 44 toward the inner surface of the product tank 14. As a result, the product 12 attached to the inner surface of the product tank 14 is removed. Further, since the fresh water flowing in the product tank 14 passes through the first valve 20, the product pump 16, and the processing equipment 18, the first valve 20, the product pump 16, the processing equipment 18 and the production for connecting them. The product 12 attached to the inner surface of the product supply pipe 24 is also removed.

  Then, the fresh water that has passed through the processing device 18 flows to the second valve 22 and the fifth valve 48 through the product supply pipe 24. The second valve 22 and the fifth valve 48 are alternately opened and closed, thereby eliminating a dead space where fresh water does not flow on the inlet side of the second valve 22 and the inlet side of the fifth valve 48. And when flowing fresh water through the 2nd valve | bulb 22, this fresh water flows into the following process and the product 12 of the next process is removed. When flowing fresh water through the fifth valve 48, this fresh water is sent to the sixth valve 50 and the seventh valve 52 through the drainage pipe 46. And the 7th valve | bulb 52 is opened and the fresh water which passed the drainage piping 46 is sent to a drainage device. At this time, since the inlet side of the sixth valve 50 becomes a dead space where fresh water does not flow, the sixth valve 50 is periodically opened to eliminate the dead space. The fresh water that has passed through the sixth valve 50 is also sent to the drainage device.

  When the cleaning of the product tank 14 is completed in this way, the fourth valve 42 is closed and the third valve 38 is opened to roughly clean the product supply pipe 24 after the portion where the liquid feeding pipe 34 is connected. To do. The rough cleaning may be performed in the same manner as the rough cleaning of the product tank 14 described above.

  When such rough cleaning is completed, an alkaline cleaner (cleaning liquid) is then flowed to perform CIP. This is because the liquid feed pump 36 is operated to allow the alkaline detergent to flow from the detergent tank 32, and a gas such as air is supplied from the first gas pipe 40 to the liquid feed pipe 34 so that the alkaline detergent and the gas are mixed. CIP is performed in a gas-liquid two-phase flow. In addition, since the conditions for inflowing the gas from the first gas pipe 40 can be changed as appropriate, the gas supply amount may be kept constant, the supply amount may be changed, or the gas may be supplied intermittently. it can. Moreover, the pressure of the gas supplied from the 1st gas piping 40 is fluctuate | varied, and the dimension of the bubble which comprises a gas-liquid two-phase flow can also be fluctuate | varied.

  As an example, the flow rate of the alkali cleaning agent is 1 to 3 [m / s], the gas supply amount is 0.001 to 0.1 [%] (volume ratio V / V of gas to the alkali cleaning agent), and gas What is necessary is just to fluctuate supply_amount | feed_rate of gas and an alkali cleaning agent so that a pressure may become in the range of 0.5 [MPa] or more larger than 0. The supply amount fluctuation condition can be set as appropriate by performing experiments and simulations according to the shape of the product production line 10 and the like.

  The interval at which the gas is intermittently supplied can be arbitrarily set, for example, in a range longer than 0 minutes and not longer than 5 minutes. That is, when the product supply pipe 24 is branched in the middle, and the gas-liquid two-phase flow gas is easily collected at the branched position, the gas is supplied at intervals such that the gas does not always accumulate at the branched position. May be supplied intermittently.

  When such a gas-liquid two-phase flow is caused to flow through the product supply pipe 24, the disturbance of the fluid flowing through the product pump 16, the processing equipment 18, and the product supply pipe 24 is promoted, and the cleaning with the alkaline detergent is promoted. To do. The cleaning by the gas-liquid two-phase flow obtained by mixing the alkali cleaning agent and the gas may be performed in the same manner as the rough cleaning described above, but depending on the concentration of the alkaline cleaning agent that has passed through the fifth valve 48. Thus, the opening and closing of the sixth valve 50 and the seventh valve 52 may be switched.

  That is, when the alkaline detergent is consumed by washing the product manufacturing line 10 and the concentration of the alkaline detergent is lowered, the seventh valve 52 is opened and the sixth valve 50 is opened to send the alkaline detergent to the drainage device. close. On the other hand, if the alkali concentration is higher than the predetermined concentration even after cleaning the product manufacturing line 10, the sixth valve 50 is opened and the seventh valve 52 is closed to return the alkaline cleaning liquid to the cleaning agent tank 32 for circulation. . When the cleaning in the gas-liquid two-phase flow obtained with such an alkali cleaning agent and gas is completed, the alkaline cleaning agent is removed by rinsing with fresh water.

  Then, CIP is performed by flowing an acid cleaning agent (cleaning liquid). This is because the liquid feed pump 36 is operated to flow the acid detergent from the detergent tank 32 and a gas such as air is supplied from the first gas pipe 40 to the liquid feed pipe 34 so that the acid detergent and the gas are mixed. CIP is performed in a gas-liquid two-phase flow. In addition, since the conditions for inflowing the gas from the first gas pipe 40 can be changed as appropriate, the gas supply amount may be kept constant, the supply amount may be changed, or the gas may be supplied intermittently. it can. The conditions for changing the gas supply amount and the timing for intermittently supplying the gas can be the same as in the case of performing the CIP by flowing the alkali cleaning agent. Moreover, the pressure of the gas supplied from the 1st gas piping 40 is fluctuate | varied, and the dimension of the bubble which comprises a gas-liquid two-phase flow can also be fluctuate | varied. When such a gas-liquid two-phase flow is caused to flow through the product supply pipe 24, disturbance of the fluid flowing through the product pump 16, the processing equipment 18, and the product supply pipe 24 is promoted, and cleaning with the acid detergent is promoted. To do. And the washing | cleaning by the gas-liquid two-phase flow obtained by mixing an acid cleaning agent and gas should just perform operation similar to the alkali washing | cleaning mentioned above. When the cleaning with the gas-liquid two-phase flow obtained with the acid cleaning agent and the gas is finished, the cleansing water is supplied from the cleaning agent tank 32 to remove the acid cleaning agent. When this final rinsing is performed, an operation similar to the rough cleaning may be performed.

  According to such a line cleaning method, a gas-liquid two-phase flow is obtained by flowing a gas such as air from the first gas pipe 40, and the product manufacturing line 10 is cleaned with this gas-liquid two-phase flow. The cleaning of the inner surface of the product manufacturing line 10 can be promoted, and the cleaning time can be reduced. That is, when air or the like is flowed from the first gas pipe 40 during alkali cleaning or acid cleaning, the product pump 16, the product supply pipe 24, and the processing equipment 18 promote flow disturbance due to the gas-liquid two-phase flow. And cleaning with a cleaning agent can be promoted.

  Further, when a gas-liquid two-phase flow is used for alkali cleaning or acid cleaning, it is conceivable that a gas pool is generated in the product manufacturing line 10 and that portion cannot be cleaned. However, by intermittently supplying the gas, it is possible to prevent the occurrence of gas accumulation, and it is possible to clean the product manufacturing line 10 reliably. Furthermore, when performing the CIP using the gas-liquid two-phase flow, if the gas supply amount fluctuates, the flow of the gas-liquid two-phase flow can be changed. Cleaning performance can be improved.

  Further, when the product manufacturing line 10 is cleaned using the gas-liquid two-phase flow, the cleaning effect of the product manufacturing line 10 can be increased by changing the pressure of the gas supplied from the first gas pipe 40. Can be changed, and a wide range can be washed. The gas pressure can be periodically changed. In this case, the wide range of the product production line 10 can be washed uniformly.

Next, a first embodiment according to the present invention will be described. In the first embodiment described above, the line cleaning method in the case where one gas pipe is provided in the line cleaning device 30 has been described. However, a plurality of gas pipes may be provided in the line cleaning device 30. This is to avoid the following situation. That is, in the case of flowing gas into a line from a normal gas inflow valve, when the amount of gas supplied to the product manufacturing line 10 is large, the gas (bubbles) are united on the downstream side, and the upper and lower parts separated into gas and liquid are separated. There is a possibility of becoming a two-phase flow. If it becomes like this, since it becomes impossible to wash | clean the product manufacturing line 10 reliably, in order to prevent generation | occurrence | production of an up-and-down two-phase flow, the line washing | cleaning apparatus 30 is provided with multiple inflow locations of gas.

  FIG. 2 is a schematic system diagram of a product production line equipped with a line cleaning apparatus provided with a plurality of gas pipes. FIG. 2 shows a form in which a first gas pipe 40 and a second gas pipe 60 are provided as an example of the line cleaning device 30 provided with a plurality of gas pipes. And FIG. 2 differs only in the point which provided the 2nd gas piping 60 compared with the form shown in FIG.

  The second gas pipe 60 may be provided on the upstream side of the location where the gas-liquid two-phase flow obtained by supplying gas from the first gas pipe 40 becomes the upper and lower two-phase flow. In addition, when there is a portion (dead space) where the gas-liquid two-phase flow does not flow in the product manufacturing line 10, as an example, when the product supply pipe 24 is branched, the gas-liquid is supplied to the branch portion. In the case where a two-phase flow does not flow in, the second gas pipe 60 may be provided upstream near this dead space. Thereby, before the gas-liquid two-phase flow flowing through the product manufacturing line 10 becomes the upper and lower two-phase flow, the gas-liquid two-phase flow is obtained by the gas supplied from the second gas pipe 60, and the upper and lower two-phase flow is obtained. It is possible to prevent the product production line 10 from being washed. Moreover, since the location (dead space) where a gas-liquid two-phase flow does not flow into the product manufacturing line 10 does not occur, the product manufacturing line 10 can be reliably cleaned.

  In the case shown in FIG. 2, the second gas pipe 60 is connected to the product supply pipe 24 between the product pump 16 and the processing equipment 18 so that a gas such as air is supplied to the product supply pipe 24. It has become. And the gas is supplied from the 2nd gas piping 60, when performing CIP using an alkali cleaning agent or an acid cleaning agent similarly to embodiment mentioned above. Thereby, also with the gas supplied from the 2nd gas piping 60, it mixes with an alkali cleaning agent or an acid cleaning agent, and a gas-liquid two-phase flow is obtained.

  Note that the gas may be supplied simultaneously from the first gas pipe 40 and the second gas pipe 60, or the gas may be supplied alternately from the gas pipes 40, 60. Further, among the first gas pipe 40 and the second gas pipe 60, gas is always supplied from one gas pipe, gas is supplied intermittently from the other gas pipe, or the gas supply amount is varied. Also good. The pressure of the gas supplied from at least one of the first gas pipe 40 and the second gas pipe 60 may be varied. Furthermore, these may be used in combination.

  In this way, when the plurality of gas pipes 40 and 60 are provided in the line cleaning device 30, a change occurs in the flow of the gas-liquid two-phase flow as compared with the case where the gas-liquid two-phase flow is obtained by supplying the gas from one place. Since the location can be changed, cleaning of the inner surface of the product manufacturing line 10 can be promoted, and the cleaning time can be reduced. That is, when the location where the gas flows into the product manufacturing line 10 or the liquid feeding pipe 34 is fixed at one location, the cleaning area is limited to some extent due to the change in the gas inflow ratio (the ratio of the gas to the cleaning liquid). Although it can be changed, as shown in FIG. 2, if the gas is allowed to flow into the product manufacturing line 10 or the liquid supply pipe 34 from a plurality of locations, the cleaning region can be further changed. When the gas is introduced from a plurality of locations, the cleaning region can be further changed by changing the inflow ratio of the gas from each location.

Next, a second embodiment will be described. As described in the second embodiment, the gas-liquid two-phase flow that flows through the product manufacturing line 10 may become an upper and lower two-phase flow separated into a gas and a liquid. In order to prevent the occurrence of such an upper and lower two-phase flow, the line cleaning device 30 can include a fluid mixer.

  FIG. 3 is an explanatory view of a part of a product production line equipped with a line cleaning device provided with a fluid mixer. The fluid mixer 70 has an element (not shown) provided inside the liquid feeding pipe 34 and the product supply pipe 24, and the fluid flowing inside is mixed by this element. Therefore, the fluid mixer 70 may be provided upstream from the location where the gas-liquid two-phase flow is separated from the gas pipe 70 into gas and liquid. Thereby, it can prevent that the gas-liquid two-phase flow which flows through the liquid feeding piping 34 and the product manufacturing line 10 turns into a two-phase flow. Further, another gas pipe 74 can be provided on the downstream side of the fluid mixer 70. Therefore, in the case where the two gas pipes 40 and 60 described in the second embodiment are provided, the fluid mixer 70 can be provided between the first gas pipe 40 and the second gas pipe 60, and the second gas. A fluid mixer 70 may be provided on the downstream side of the pipe 60.

  As such a fluid mixer 70, for example, a static mixer can be used. This static mixer has a plurality of elements arranged inside along the length direction of the liquid feeding pipe 34 and the product supply pipe 24, and the fluid flowing through the inside is mixed by this element. Yes.

It is a schematic system diagram of the product manufacturing line provided with the line washing apparatus. It is a schematic system diagram of the product manufacturing line which attached the line washing | cleaning apparatus provided with several gas piping. It is explanatory drawing of a part of product production line which attached the line washing | cleaning apparatus provided with the fluid mixer.

Explanation of symbols

10 ... Production line, 12 ... Production product, 16 ... Production pump, 18 ... Processing equipment, 20 ... First valve, 22 ... Second valve, 24 ... ... Product supply piping, 30 ......... Line cleaning equipment, 31 ......... CIP equipment, 32 ......... Cleaning agent tank, 34 ......... Liquid feeding piping, 36 ......... Liquid feeding pump, 38 ......... No. 3 valves, 40 ......... first gas piping, 42 ......... fourth valve, 46 ......... drain piping, 48 ...... 5th valve, 60 ......... second gas piping, 70 ......... fluid Mixing machine.

Claims (6)

A gas is supplied to the inside of the line from a plurality of gas pipes connected from the upstream side to the downstream side of the line, and a cleaning liquid is supplied to the inside of the line to generate a gas-liquid two-phase flow. a line wash method of the interior of the stationary cleaning,
When connecting the plurality of gas pipes from the upstream side to the downstream side of the line, upstream from the point where the gas-liquid two-phase flow obtained by supplying gas from the gas pipe on the upstream side becomes an upper and lower two-phase flow While connecting the gas pipe on the downstream side to supply gas to the inside of the line,
A line cleaning method , wherein the inside of the line is cleaned by changing the amount of gas flowing into the line.   2. The line cleaning method according to claim 1, wherein the inflow of gas into the line is intermittently performed, and the inside of the line is cleaned alternately with the gas-liquid two-phase flow and the cleaning liquid. Of the gas pipe connected to the upstream side of the line and the gas pipe connected to the downstream side, gas is always supplied from one of the gas pipes, and gas is supplied intermittently from the other gas pipe. The line cleaning method according to claim 1, wherein: The line cleaning method according to any one of claims 1 to 3 , wherein the size of bubbles constituting the gas-liquid two-phase flow is changed by changing a pressure of gas supplied from the gas pipe. A gas-liquid two-phase flow is generated by providing means for mixing fluid flowing in the line between the gas pipe connected to the upstream side of the line and the gas pipe connected to the downstream side. A line cleaning method according to any one of claims 1 to 4. A line cleaning device that performs stationary cleaning inside the line,
Means for supplying a cleaning liquid to the line;
Supplying a gas to the line, and a first gas pipe for obtaining a gas-liquid two-phase flow of the cleaning liquid and the gas inside the line;
Supplying gas to the line on the upstream side of the part where the gas-liquid two-phase flow becomes an upper and lower two-phase flow downstream of the line from the connection part of the first gas pipe, and cleaning the inside of the line A second gas pipe for obtaining a gas-liquid two-phase flow of the working liquid and the gas;
The first gas pipe and said line than locations is connected a downstream of said line, provided on the upstream side of the line than locations and the said second gas pipe line is connected, Means for mixing fluid flowing in the interior of the line ,
The line cleaning apparatus according to claim 1, wherein the first gas pipe and the second gas pipe vary the amount of gas flowing into the line.

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