JP2008200564A - Wastewater sterilizing apparatus and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wastewater sterilizing apparatus which can be simply and inexpensively structured, obtain a sufficient sterilization effect on heating, has high safety without the risk of discharging unsterilized wastewater to be treated, and dispenses with a filter for sterilization attached to a vacuum pump to enable further cost reduction, and a wastewater sterilizing method. <P>SOLUTION: The wastewater sterilizing apparatus 10 for sterilizing experimental wastewater supplied into a sterilizing tank 20 by heating with an electric heater 30 installed in the sterilizing tank 20 is equipped with a vacuum pump 40 for changing pressure in the sterilizing tank 20. The temperature of the experimental wastewater is increased by actuation of the electric heater 30 to increase the pressure in the sterilizing tank 20 to a predetermined value or higher, and then the pressure in the sterilizing tank 20 is temporarily reduced by operation of the vacuum pump 40 to cause a pressure change therein, thereby forcibly generating convection in the experimental wastewater. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a wastewater sterilization apparatus and a wastewater sterilization method for heating and sterilizing a wastewater to be treated supplied in a sealed tank by a heating means.

  Conventionally, as this type of wastewater sterilization apparatus, for example, one having a sterilization tank (tank) for receiving infectious wastewater to be sterilized and a steam heating means for heating the infectious wastewater in the sterilization tank is known. (See Patent Documents 1 and 2). The steam heating means sends steam into a jacket installed on the outer periphery of the sterilization tank so that the heat of the steam acts on the infectious waste water inside through the wall surface of the sterilization tank. In the sterilization tank, no means for forcibly causing thermal convection was provided, and it was left to natural convection only by raising the temperature of infectious wastewater.

  In the waste water sterilizer, waste water after sterilization by heating was drained by opening a valve provided in a drain pipe connected to the bottom of the sterilization tank. In the sterilization tank, infectious wastewater once stored in a drainage pit (drainage tank) is vacuum-sucked by a vacuum pump. In order to connect the vacuum pump and the sterilization tank, a filter for trapping bacteria that may be contained in the suction air when the air in the sterilization tank is sucked is interposed in the pump pipe.

JP 2003-53326 A JP 2004-313979 A

  However, in the conventional wastewater sterilization apparatus as described above, since the heating method for sterilization is an indirect heating method using steam heating means for feeding steam into a jacket installed on the outer periphery of the sterilization tank, The overall structure is complicated and large, the number of parts increases, the number of assembling steps increases, and there is a problem that the cost increases.

  Further, at the time of heating in the sterilization tank, the temperature of the infectious waste water in the sterilization tank was increased only by natural convection even in the indirect heating method. Therefore, the temperature distribution of infectious wastewater is poor and the upper part of the sterilization tank rises to a predetermined temperature, whereas the lower part does not rise sufficiently to the predetermined temperature, causing temperature unevenness and the sterilization effect is reduced. There was a problem.

  In particular, in the case of a conventional general apparatus configuration in which a heater is installed in a sterilization tank and heated directly, for example, instead of the indirect heating method, the configuration of the entire apparatus can be simplified. In the sterilization tank, there is a problem that the temperature does not rise unless it is above the heater arrangement position. It is presumed that this is because convection does not occur because the pressure of the upper air layer in the sterilization tank rises to prevent the flow of infectious wastewater.

  In addition, since the drainage after sterilization was drained from the drainage pipe connected to the bottom of the sterilization tank, infectious wastewater stored in the bottom of the sterilization tank and the drainage valve pipe did not cause convection during heating. Moreover, since the heat of the steam heating means was not transmitted, the predetermined sterilization temperature was not reached. Therefore, there is a problem that infectious waste water that has not been sterilized is drained and is not safe.

  Furthermore, since the vacuum pump is equipped with a filter for trapping bacteria that may be contained in the suction air from the sterilization tank, extra and expensive parts are required and the filter is clogged. In such a case, the vacuum pump is overloaded, and there is a problem that the drainage sterilizer stops or causes a failure.

  The present invention has been made paying attention to the problems of the prior art as described above, and the entire apparatus can be constructed simply and inexpensively, and sufficient sterilization can be achieved by forcibly causing convection during heating. It is possible to obtain an effect, and there is no risk that untreated wastewater to be treated is discharged, and the safety is high. Furthermore, a sterilization filter attached to the vacuum pump is unnecessary, and the cost can be further reduced. It aims at providing a drainage sterilizer and a drainage sterilization method.

The gist of the present invention for achieving the object described above resides in the inventions of the following items.
[1] In a wastewater sterilization apparatus (10) for heating and sterilizing the wastewater to be treated supplied into the sealed tank (20) by the heating means (30),
Pressure changing means (40) for changing the pressure in the tank (20),
After the temperature of the wastewater to be treated rises due to the operation of the heating means (30) and the pressure in the tank (20) becomes a predetermined value or more, the inside of the tank (20) is activated by the operation of the pressure changing means (40). A drainage sterilizer (10) characterized by forcibly generating convection in the wastewater to be treated by temporarily reducing the pressure and changing the pressure in the tank (20).

  [2] When the temperature of the wastewater to be treated rises due to the operation of the heating means (30) and the pressure in the tank (20) becomes a predetermined value or more, the operation of the heating means (30) is temporarily stopped and predetermined After a lapse of time, the pressure in the tank (20) is temporarily reduced by the operation of the pressure changing means (40) to change the pressure in the tank (20), thereby forcing the wastewater to be treated. [1] characterized in that after generating convection and stopping the operation of the pressure changing means (40), the heating means (30) is operated again to raise the temperature of the wastewater to be treated to a predetermined temperature. The wastewater sterilizer (10) as described.

[3] It has a vacuum pump (40) for vacuum suctioning the wastewater to be treated stored in the drainage tank (1) and feeding it into the tank (20),
The drainage sterilization apparatus (10) according to [1] or [2], wherein the vacuum pump (40) is also used as the pressure changing means (40).

[4] The vacuum pump (40) is composed of a casing and an impeller rotatably disposed therein, and continuously introduces sealing liquid into the casing to rotate the impeller, thereby continuously It consists of a water-sealed vacuum pump (40) that can be inhaled,
According to [3], when the sealing liquid mixed with the air sucked from the tank (20) in the casing is discharged, the sealing liquid is introduced into the drainage tank (1) without a filter. Waste water sterilizer (10).

[5] The upstream end side of the drain pipe (55) is introduced into the tank (20) so as to extend from the top to the bottom, and the downstream end of the drain pipe (55) is the upstream end. It is arranged to open at a position lower than the opening on the side,
The treated waste water sterilized in the tank (20) is discharged out of the tank (20) by the siphon principle through the drain pipe (55), [1], [2], The drainage sterilizer (10) according to [3] or [4].

  [6] The pressure in the tank (20) is used when filling the drainage pipe (55) to be treated with sterilized wastewater to start the siphon. Waste water sterilizer (10).

[7] In the wastewater sterilization method for heating and sterilizing the wastewater to be treated supplied into the sealed tank (20) by the heating means (30),
A suction step, a temperature raising step, a sterilization step, and a drainage step,
The suction step is a step of sucking the wastewater to be treated stored in the drain tank (1) into the tank (20) by vacuum suction by the operation of the vacuum pump (40),
The temperature raising step temporarily stops the operation of the heating means (30) when the temperature of the wastewater to be treated rises due to the operation of the heating means (30) and the pressure in the tank (20) exceeds a predetermined value. Then, after a predetermined time has elapsed, the operation of the vacuum pump (40) temporarily depressurizes the tank (20) to change the pressure in the tank (20), thereby forcing the wastewater to be treated. Convection is generated, and after the operation of the vacuum pump (40) is stopped, the heating means (30) is operated again to raise the temperature of the wastewater to be treated to a predetermined temperature,
The sterilization step is a step of sterilizing the wastewater to be treated while maintaining the predetermined temperature,
In the draining step, the upstream end side is introduced into the tank (20) so as to extend from the top to the bottom, and the downstream end is opened at a position lower than the opening on the upstream end side. By the drainage pipe (55) thus formed, the treated wastewater in the tank (20) is discharged out of the tank (20) by the siphon principle, and the drainage pipe (55) is used to start the siphon. ) Is a step of utilizing the pressure in the tank (20) when filling the sterilized wastewater to be treated.

Next, the operation based on the above solution will be described.
In the wastewater sterilization apparatus (10) according to the present invention, in order to simplify the configuration of the wastewater sterilization apparatus (10) and realize cost reduction, the heating means (30) for sterilization is replaced with the conventional steam heating described above. For example, it is effective to use a heater built in the tank (20) instead of the indirect heating method. However, in the case of the direct heating method using a heater, natural convection of the wastewater to be treated hardly occurs in the tank (20), so the temperature did not rise unless it was above the heater placement position.

  In order to solve such a problem, it is necessary to generate convection in the wastewater to be treated in the tank (20) during heating. According to the research by the inventors, the wastewater sterilizer described in [1] above As in (10), after the temperature of the wastewater to be treated rises due to the operation of the heating means (30) and the pressure in the tank (20) becomes a predetermined value or more, the tank ( 20) It was found that convection can be forcedly generated in the wastewater to be treated by temporarily reducing the pressure in the tank and changing the pressure in the tank (20).

  Thereby, even if it is a case where the structure of the whole apparatus is simplified as a heater equipped in the tank (20), for example, the said heating means (30) is forced regardless of the kind of heating means (30). Since convection can be generated, the cost can be reduced, the water temperature distribution in the tank (20) can be made uniform, and temperature unevenness in the wastewater to be treated does not occur, and a desired sterilization temperature can be obtained in the entire region. It becomes possible to heat to.

  More specifically, as in the drainage sterilization apparatus (10) described in [2] above, the temperature of the wastewater to be treated rises due to the operation of the heating means (30), and the pressure in the tank (20) exceeds a predetermined value. When a predetermined time has elapsed after the operation of the heating means (30) is temporarily stopped, the pressure in the tank (20) is temporarily reduced by the operation of the pressure changing means (40). By changing the internal pressure, convection can be forcibly generated in the wastewater to be treated. After the operation of the pressure changing means (40) is stopped, the heating means (30) is operated again to raise the temperature of the wastewater to be treated to a predetermined temperature.

  By the way, like the drainage sterilization apparatus (10) of the above [3], the wastewater to be treated stored in the drainage tank (1) is vacuum-sucked by the vacuum pump (40) into the tank (20). In this case, the vacuum pump (40) may be used as the pressure changing means (40). Thereby, it is not necessary to prepare the pressure changing means (40) separately, and the configuration of the entire apparatus can be further simplified by using the vacuum pump (40) which is an essential configuration as it is.

  Here, the vacuum pump (40) is specifically composed of a casing and an impeller rotatably disposed therein as described in [4], for example. It is good to comprise from the water-seal type | formula vacuum pump (40) which can be inhaled continuously by introduce | transducing and rotating an impeller.

  In this case, when the sealing liquid mixed with the air sucked from the tank (20) in the casing is discharged, it is introduced into the drainage tank (1) without passing through a filter. Thereby, since the water for water sealing is heat-sterilized, the filter for sterilization becomes unnecessary. Therefore, the drainage sterilization device (10) is not stopped due to the clogging of the filter, there is no risk of failure, and the maintenance of the filter is not necessary.

  Further, according to the drainage sterilization apparatus (10) described in [5], the upstream end side of the drainage pipe (55) is introduced into the tank (20) so as to extend from the top to the bottom. The drainage pipe (55) is arranged so that the downstream end side is opened at a position lower than the opening part on the upstream end side, and the sterilized treated wastewater is the drainage pipe (55 ) Is discharged out of the tank (20) by the siphon principle.

  As a result, conventionally, a drainage pipe is generally connected to the bottom of the tank (20) so as to communicate with it, or a drainage valve that opens and closes in the middle of this connection or drainage pipe. However, these configurations are unnecessary. Become. In addition, there is no possibility of discharging the wastewater to be treated which is insufficiently heated and stored in the bottom of the tank (20) and the drain pipe, and safety and reliability can be improved. The drainage is from the bottom of the tank (20) until air is sucked and the siphon action is interrupted, and the treated wastewater at the bottom of the tank (20) that may not be sterilized is not discharged.

  Here, as described in [6] above, when filling the wastewater to be sterilized in the drainage pipe (55) to start the siphon, the pressure in the tank (20) is used as it is. This eliminates the need for a special suction operation or device for starting the siphon. If the pressure in the tank (20) is immediately after sterilization by heating, the wastewater to be treated or the upper layer air in the tank (20) is heated to increase pressure from the normal atmospheric pressure due to volume expansion. It has become a state.

  Furthermore, the drainage sterilization method described in the above [7] is suitable as a specific treatment using the drainage sterilization apparatus (10) described in the above [1] to [6]. That is, as a cycle of sterilization treatment, at least a suction step, a temperature raising step, a sterilization step, and a drainage step are performed, and control is performed so that all can be performed automatically.

In the suction step, the wastewater to be treated stored in the drain tank (1) is vacuum-sucked by the operation of the vacuum pump (40) and sent into the tank (20).
In the temperature raising step, when the wastewater to be treated is heated by the operation of the heating means (30) and the pressure in the tank (20) becomes a predetermined value or more, the operation of the heating means (30) is temporarily stopped. After a predetermined time has elapsed, the tank (20) is temporarily depressurized by operating the vacuum pump (40) to change the pressure in the tank (20), thereby forcibly convection to the wastewater to be treated. After the operation of the vacuum pump (40) is stopped, the heating means (30) is operated again to raise the temperature of the wastewater to be treated to a predetermined temperature.

In the sterilization step, the wastewater to be treated is sterilized while maintaining the predetermined temperature.
In the draining step, the upstream end side is introduced into the tank (20) so as to extend from the top to the bottom, and the downstream end is opened at a position lower than the opening on the upstream end side. The treated waste water in the tank (20) is discharged out of the tank (20) by the siphon principle by the drainage pipe (55) thus made. Here, in order to start the siphon, when the drainage pipe (55) is filled with the sterilized wastewater to be treated, the pressure in the tank (20) is used.

  According to the waste water sterilization apparatus and the waste water sterilization method of the present invention, the pressure in the tank is changed by the operation of the pressure changing means, thereby forcibly generating convection in the treated waste water regardless of the type of the heating means Therefore, it is possible to reduce the cost and to make the water temperature distribution in the tank uniform, and it is possible to heat to the desired sterilization temperature in the entire area without causing temperature unevenness in the wastewater to be treated. Become. Here, in addition to the pressure changing means, there is no need for any special means (air mixing, stirring propeller, etc.) for forcibly causing convection.

  The vacuum pump also serving as the pressure changing means is a water-sealed vacuum pump, and when discharging the sealing liquid mixed with the air sucked from the tank in the casing of the water-sealed vacuum pump, Since the water for sealing is heat sterilized by introducing it into the drainage tank, no filter for sterilization is required, and there is no risk of equipment shut down or failure due to filter clogging. Is also unnecessary.

  Furthermore, the waste water to be treated in the tank is discharged outside the tank using the siphon principle by drainage piping, so that a drain pipe connected to the bottom of the tank is generally unnecessary, and the tank bottom Therefore, there is no risk of discharging the wastewater to be treated which is insufficiently heated, and safety and reliability can be improved.

In the following, an embodiment representing the present invention will be described with reference to the drawings.
1 to 8 show an embodiment of the present invention.
FIG. 1 is a conceptual diagram of a wastewater sterilization apparatus according to an embodiment of the present invention. FIG. 2 is a perspective view schematically showing a main part of the drainage sterilizer. FIG. 3 is a front view showing the appearance of the main part of the drainage sterilization apparatus.

  The drainage sterilization apparatus 10 according to the present embodiment includes a heater (heating means) 30 in which experimental wastewater (treated wastewater) supplied in a sterilization tank (sealed tank) 20 is built in the sterilization tank 20. This is a device for heating and sterilizing by means of. Hereinafter, the case where it applies to the apparatus for heat-sterilizing the experimental waste_water | drain (to-be-processed waste water) which comes out in a gene recombination experiment is demonstrated to an example.

  As shown in FIG. 1, the drainage sterilizer 10 includes a sterilization tank 20, an electric heater 30, a vacuum pump 40, a control panel (not shown), and the like housed in a housing 11 (see FIG. 2) that constitutes the apparatus body. A pipe and an experimental drainage tank (drainage tank) 1 and a drainage tank 2 disposed outside the housing 11 are provided. The experimental drainage tank 1 is a water tank for storing the experimental wastewater drained from the laboratory to a specified water level, and the drainage tub 2 is a tank for receiving sterilized experimental wastewater.

  The sterilization tank 20 is a simple pressure vessel constructed in a sealed manner as a cylindrical can with a single wall structure. The upper surface is a flat plate and the bottom is a hemispherical end plate. In order to keep warm, a glass wool layer may be attached to the outer periphery. In the sterilization tank 20, two water level sensors 21 and 22 are provided for detecting different height positions of the supplied experimental waste water. In addition, an electric heater 30 is disposed in a substantially horizontal height position in the sterilization tank 20 so as to extend substantially horizontally just below the water level sensor 22 positioned below.

  Specifically, for example, a round bar-shaped flange heater or a plug heater may be used as the electric heater 30. The position of the electric heater 30 in the sterilization tank 20 is preferably provided at the bottom of the tank in terms of heating efficiency, but the electric heater 30 is not at the bottom of the tank because there is a maintenance problem such as periodic replacement. It is disposed at a substantially intermediate height position in the tank shown in FIG. A temperature sensor 23 is disposed near the bottom of the sterilization tank 20. Thus, it can be determined that the vicinity of the bottom in the sterilization tank 20 has reached a predetermined temperature.

  Further, a vacuum pump 40 is connected to the sterilization tank 20 through a pipe. The vacuum pump 40 is a water-sealed type, and is composed of a casing and an impeller rotatably disposed therein, and the impeller is attached at a position eccentric to the casing. By introducing the sealing liquid into the casing and rotating the impeller, the sealing liquid is set to be pressed against the inner wall of the casing by centrifugal force to form a water ring.

  In the casing, the volume of the space surrounded by the inner wall of the ring of water and the blades of the impeller is attached at a position eccentric from the casing, so that the volume changes as the impeller rotates. . Utilizing this volume change, the suction, compression, and exhaust operations can be performed continuously.

  Furthermore, as shown in FIG. 1, various pipes are connected to the sterilization tank 20 and the vacuum pump 40 so as to communicate with each other. The pipes constituting the drainage sterilization apparatus 10 according to the present embodiment include a water supply pipe 51, a vacuum pump intake pipe 52, an experimental drain suction pipe 53, a vacuum pump drain pipe 54, and a sterilized drain pipe 55. Etc. are arranged in place. In addition, as will be described later, electromagnetic valves, manual valves, and the like are disposed throughout the various pipes.

  The upstream end of the water supply pipe 51 is connected to a city water faucet (not shown) outside the apparatus, and the downstream side is extended into the apparatus and branched into two paths. The downstream end of one branched first water supply pipe 51A is connected to the vacuum pump 40, and the downstream end of the other second water supply pipe 51B is mixed in the middle of the downstream side of a sterilized drainage pipe 55 described later. The valve 501 is connected.

  In the middle of the water supply pipe 51, a manual valve 511, a pressure gauge 551, and a pressure switch 561 are arranged in order from the upstream side connected to the water tap. A manual valve 512 and an electromagnetic valve 521 are disposed in the middle of the first water supply pipe 51A. Further, an electromagnetic valve 522 is disposed in the middle of the second water supply pipe 51B.

  The vacuum pump intake pipe 52 is connected to communicate between the vacuum pump 40 and the upper part (air layer) of the sterilization tank 20, and the vacuum pump 40 is operated from the vacuum pump intake pipe 52 by the operation of the vacuum pump 40. The air inside is sucked out and depressurized. A check valve 531, an electromagnetic valve 523, a strainer 571, a pressure gauge 552, and pressure switches 562 to 564 are disposed in the middle of the vacuum pump intake pipe 52 in this order from the vacuum pump 40 side. The pressure in the sterilization tank 20 can be measured by the pressure gauge 552 and the pressure switches 562 to 564.

  The upstream end of the experimental drainage suction pipe 53 extends to the inside of the experimental drainage tank 1, and the downstream end is connected to the upper part of the sterilization tank 20. A manual valve 513, a strainer 572, a solenoid valve 524, and a check valve 532 are arranged in order from the upstream side of the experimental drainage suction pipe 53.

  The vacuum pump drain pipe 54 is connected to the vacuum pump 40 so as to communicate with the first water supply pipe 51A, and the downstream end is extended to a position facing the inside of the experimental drain tank 1. Yes. The vacuum pump drain pipe 54 is a pipe for discharging the sealed water used in the vacuum pump 40. Thus, when discharging the sealing liquid mixed with the air sucked from the sterilization tank 20 in the casing of the vacuum pump 40, it is set so as to be introduced into the experimental drain 1 without going through the sterilization filter. Yes.

  The sterilized drainage pipe 55 is introduced into the sterilization tank 20 so that its upstream end extends from the top of the sterilization tank 20 toward the bottom, and the downstream end is at a position lower than the opening on the upstream end side. It extends to a position facing the drainage basin 2 so as to open. In the middle of the sterilized drainage pipe 55, a strainer 573, a manual valve 514, an electromagnetic valve 525, a mixing valve 501 connected to the downstream end of the second water supply pipe 51B, and a temperature sensor 581 are sequentially provided from the upstream side. Each is arranged.

  The experimental waste water that has been sterilized in the sterilization tank 20 is configured to be discharged out of the sterilization tank 20 by the sterilization-treated drain pipe 55 on the principle of siphon. Here, in order to start the siphon, when filling the sterilized drainage pipe 55 with the sterilized experimental effluent, the pressure in the sterilization tank 20 is used as will be described in detail later.

  The upstream end of the experimental waste water return pipe 56 is connected to the bottom of the sterilization tank 20. This experimental drainage return pipe 56 is originally unnecessary, but is provided for maintenance of the sterilization tank 20. The upstream end of the safety valve relief pipe 57 is connected to the upper part of the sterilization tank 20. The safety valve relief pipe 57 is for depressurizing the inside of the sterilization tank 20 when the inside of the sterilization tank 20 is abnormal in pressure.

Next, the operation of the drainage sterilization apparatus 10 according to the present embodiment will be described.
By adopting the electric heater 30 as the heating means in the wastewater sterilization apparatus 10, the configuration can be simplified and the cost can be reduced as compared with the indirect heating type apparatus. However, in the case of the direct heating method using the electric heater 30, the natural convection of the experimental waste water hardly occurred in the sterilization tank 20 in the conventional general apparatus.

  Therefore, in the present wastewater sterilization apparatus 10, after the experimental wastewater is heated by the operation of the electric heater 30 and the pressure in the sterilization tank 20 becomes a predetermined value or more, the inside of the sterilization tank 20 is temporarily moved by the operation of the vacuum pump 40. The pressure in the sterilization tank 20 is changed to a pressure to change the pressure in the sterilization tank 20 to forcibly generate convection in the experimental waste water.

  Thereby, regardless of the type of heating means such as the electric heater 30, it is possible to forcibly generate convection, so that the cost can be reduced and the water temperature distribution in the sterilization tank 20 can be made uniform. Temperature unevenness in the experimental wastewater does not occur, and it is possible to heat to the desired sterilization temperature throughout the experimental wastewater.

  The principle of forced convection of experimental effluent due to a change in pressure in the sterilization tank 20 is not necessarily clear, but in a state where the experimental effluent in the sterilization tank 20 or the upper layer air is heated and pressurized by volume expansion. It is considered that convection is forcibly generated by a sudden drop in pressure.

  It has been proved by the inventors' experiments that such a principle can be applied regardless of the capacity of the sterilization tank 20. In this drainage sterilizer 10, there is no need for any special means (air mixing, stirring propeller, etc.) for forcibly causing convection other than the vacuum pump 40 that changes the pressure in the sterilization tank 20. Become.

  More specifically, as will be described later, more specifically, when the experimental waste water rises due to the operation of the electric heater 30 and the pressure in the sterilization tank 20 exceeds a predetermined value, the operation of the electric heater 30 is temporarily stopped. After the predetermined time has elapsed, the sterilization tank 20 is temporarily depressurized by the operation of the vacuum pump 40 to change the pressure in the sterilization tank 20 to forcibly generate convection in the experimental waste water. it can.

  Here, after the operation of the electric heater 30 is temporarily stopped and a predetermined time has elapsed, by changing the pressure in the sterilization tank 20, forced convection can be generated more reliably in the experimental waste water. This has been confirmed by the inventors' experiments. As its principle, it is presumed that once the operation of the electric heater 30 is stopped, the experimental waste water cools and the specific gravity becomes heavier, so that convection is more likely to occur.

  Then, after the operation of the vacuum pump 40 is stopped, the electric heater 30 is operated again to raise the temperature of the experimental waste water to a predetermined temperature. As a result, temperature unevenness in the experimental waste water does not occur, and the entire region can be heated to a desired sterilization temperature. In addition, when heating by the operation of the electric heater 30, the operation of the vacuum pump 40 is in principle stopped, and is temporarily activated only when a pressure change in the sterilization tank 20 is generated.

  As a concrete drainage sterilization method using the drainage sterilization apparatus 10 as described above, one cycle is a total of 7 steps including a standby process, a suction process, a vacuum process, a temperature raising process, a sterilization process, a drainage process, and an aeration process. It consists of control and can be performed automatically by the drainage sterilizer 10. Among these, in particular, the four steps of the suction step, the temperature raising step, the sterilization step, and the drainage step are essential. As a basic specification of the wastewater sterilization apparatus 10 according to the present embodiment, the treatment capacity is 25 liters in one cycle, the maximum use temperature is 121 ° C., the treatment time of one cycle is about 2 hours, and the wastewater temperature is 45. It is below ℃.

Hereinafter, each process is demonstrated along the control flowchart shown in FIG.
First, the standby process is a process in which the wastewater sterilization apparatus 10 is in a standby state without operating. In the standby process, the amount of water (water level) in the experimental drainage tank 1 has not yet reached the specified amount of water for sterilization. Whether or not the amount is the specified water amount is determined by an external sensor attached to the experimental drainage tank 1. In this standby process, all the motor operated valves 521 to 525 are in a closed state. During standby, a “standby” lamp (not shown) is lit (see FIG. 4).

  The next suction step is a step of pumping the experimental waste water from the experimental waste water tank 1 into the sterilization tank 20. When the amount of water in the experimental drain 1 reaches the specified amount for sterilization, the vacuum pump 40 is activated to set the inside of the sterilization tank 20 to a negative pressure, and the experimental drain in the experimental drain 1 is sterilized by the pressure difference. Suck up inside.

  In the suction process, the electromagnetic valve 521 in the water supply pipe 51, the electromagnetic valve 523 in the vacuum pump intake pipe 52, and the electric valve 524 in the experimental waste water suction pipe 53 are opened, and the second water supply pipe 51B. The electromagnetic valve 522 at is closed. The actual path flow in this state is shown in FIG. When the experimental wastewater reaches the operating water level (for example, 25 liters) in the sterilization tank 20, the water level sensor 21 detects it. During suction, a “suction” lamp (not shown) is lit (see FIG. 4).

  As described above, the experimental wastewater stored in the experimental drainage tank 1 is vacuum sucked by the vacuum pump 40 and sent into the sterilization tank 20. By using the vacuum pump 40 as the pressure changing means, the pressure changing means can be used. It is not necessary to prepare separately, and by using the vacuum pump 40 that is an essential configuration as it is, the configuration of the entire apparatus can be further simplified.

  The vacuum process is a process for removing air from the sterilization tank 20. When the amount of water in the sterilization tank 20 reaches the specified amount of water for sterilization, the motorized valve 524 in the experimental drainage suction pipe 53 is switched to the closed state, and the vacuum pump 40 is operated as it is. Remove the air stored at the top of the. The actual path flow in such a state is shown in FIG.

  Whether or not the inside of the sterilization tank 20 is vacuum is detected by pressure switches 562 to 564 connected in the middle of the vacuum pump intake pipe 52, and the pressure in the sterilization tank 20 is, for example, less than -0.02 MPa. When this happens, the operation of the vacuum pump 40 is stopped. The pressure in the sterilization tank 20 can be measured by a pressure gauge 552 and pressure switches 562 to 564 connected in the middle of the vacuum pump intake pipe 52. When the air is vented, the “suction” lamp (not shown) is turned on (see FIG. 4).

  By the way, when discharging the sealing liquid mixed with the air sucked from the sterilization tank 20 in the casing during the operation of the vacuum pump 40 in the suction process or the vacuum process, the filter is removed by the vacuum pump drain pipe 54. Sealed water is introduced into the drain tank 1 without intervention. Thereby, since the water for water sealing is heat-sterilized, the filter for sterilization becomes unnecessary. Therefore, there is no possibility that the drainage sterilization apparatus 10 stops due to clogging of the filter or a failure occurs, and maintenance of the filter becomes unnecessary.

  The temperature raising step is a step in which the experimental waste water in the sterilization tank 20 is heated by the electric heater 30. In the temperature raising step, the operation of the vacuum pump 40 is stopped, the electromagnetic valve 521 in the water supply pipe 51, the electromagnetic valve 523 in the vacuum pump intake pipe 52, and the motor operated valve 524 in the experimental waste water suction pipe 53 are , Each in a closed state.

  Although the pressure in the sterilization tank 20 increases due to the temperature rise of the experimental waste water by heating the electric heater 30, the energization of the electric heater 30 is temporarily stopped when the pressure exceeds a predetermined value (for example, 0.05 MPa). Then, after a lapse of a predetermined time (for example, 3 minutes) from the stop of the electric heater 30, the vacuum pump 40 is temporarily operated for a short time (for example, 15 seconds) to change the pressure in the sterilization tank 20.

  That is, the inside of the sterilization tank 20 is rapidly depressurized. As a result, convection is forcibly generated in the experimental effluent, the water temperature distribution in the sterilization tank 20 can be made uniform, and temperature unevenness in the experimental effluent does not occur, and the entire experimental effluent can be heated. It becomes possible. During the operation of the vacuum pump 40, the electromagnetic valve 521 in the first water supply pipe 51A and the electromagnetic valve 523 in the vacuum pump intake pipe 52 are each temporarily opened.

  FIG. 5 is a graph showing the correlation between the temperature of experimental waste water and the passage of time. As shown in FIG. 5, in the first half of the temperature raising step, the experimental drainage in the upper layer than the electric heater 30 is gradually heated by the operation of the electric heater 30, but the experimental wastewater in the lower layer than the electric heater 30. In almost no temperature change.

  When the temperature of the experimental waste water above the electric heater 30 (detected by the temperature sensor 1 in FIG. 5) rises to 111 ° C., the pressure in the sterilization tank 20 becomes 0.05 MPa, and at this time, the electric heater 30 is energized. Is temporarily stopped. Then, after 3 minutes from the stop of the electric heater 30, if the vacuum pump 40 is temporarily operated for 15 seconds, convection is forcibly generated due to a pressure change in the sterilization tank 20, and a lower layer than the electric heater 30 is generated. The temperature of the experimental waste water (detected by the temperature sensor 2 in FIG. 5) also rises rapidly.

  When the temperatures of the upper and lower experimental effluents of the electric heater 30 become equal at 101 ° C., the electric heater 30 is energized again to raise the experimental effluent to a predetermined sterilization temperature (eg, 121 ° C.). It should be noted that during the temperature increase, a “temperature increase” lamp (not shown) is turned on (see FIG. 4).

  The sterilization step is a step of maintaining the sterilization temperature (for example, 121 ° C.) and sterilizing the experimental waste water to inactivate it. In the sterilization process, the operation of the vacuum pump 40 is stopped as in the temperature raising process, and the electromagnetic valve 521 in the water supply pipe 51, the electromagnetic valve 523 in the vacuum pump intake pipe 52, and the experimental waste water suction pipe 53. Each of the motor-operated valves 524 is in a closed state.

  The sterilization temperature in the sterilization process and the sterilization time corresponding to this temperature are set in advance. In the present embodiment, specifically, for example, the sterilization temperature is set to 121 ° C. and the sterilization time is set to 20 minutes. The electric heater 30 is turned on or off over the sterilization time so as to maintain the sterilization temperature.

  Specifically, when the temperature detected by the temperature sensor 23 (see FIG. 1) falls below 121.5 ° C., the electric heater 30 is turned on, and when it rises above 122.5 ° C., the electric heater 30 is turned off. This control is repeated over the sterilization time. During sterilization, a “sterilization” lamp (not shown) is turned on (see FIG. 4).

  The drainage process is a process of draining the experimental wastewater in the sterilization tank 20 after completion of the above-described sterilization process. In the drainage process, the solenoid valve 525 in the sterilized drainage pipe 55 and the solenoid valve 522 in the second water supply pipe 51B are opened. Specifically, the electromagnetic valve 522 in the second water supply pipe 51B is first opened, and then, for example, after 5 seconds have elapsed, the electric valve 525 in the sterilized drainage pipe 55 is preferably opened.

  As shown in FIG. 1, the sterilization tank 20 is introduced such that the upstream end side of the sterilized drainage pipe 55 extends from the upper part of the tank toward the bottom, and the downstream end side of the sterilized drainage pipe 55. Open at a position lower than the opening on the upstream end side. By the sterilized drainage pipe 55, the sterilized experimental wastewater in the sterilization tank 20 is discharged out of the sterilization tank 20 by the siphon principle.

  The pressure in the sterilization tank 20 is 0.11 MPa (11 mH20) at the time of sterilization, and the siphon can be started using this pressure as it is, so that the experimental effluent in the sterilization tank 20 can be drained out of the tank. Thus, by using the pressure in the sterilization tank 20 as it is, a special suction operation or device for starting the siphon becomes unnecessary.

  The drainage by the sterilized drainage pipe 55 is from the downstream end opening of the sterilized drainage pipe 55 extending to the bottom of the sterilization tank 20 until the siphon action is interrupted and the experimental drainage at the bottom of the sterilization tank 20 is The experimental wastewater that is not drained and may be insufficiently sterilized remains in the sterilization tank 20. Thereby, the safety | security and reliability of the waste water sterilizer 10 increase.

  The experimental wastewater discharged from the sterilization tank 20 is mixed with the cooling water (city water) supplied from the second water supply pipe 51B in the middle of the discharge, and cooled to a predetermined drainage temperature (for example, 45 ° C.) or less. It is discharged to the drainage basin 2. The actual path flow in such a state is shown in FIG. When the temperature detected by the temperature sensor 581 exceeds the waste water temperature (for example, 45 ° C.), the electric valve 525 is closed and the discharge of the experimental waste water is interrupted.

  Completion of drainage of the experimental wastewater is determined by a pressure gauge 552 in the vacuum pump intake pipe 52 communicating with the sterilization tank 20. That is, when the pressure in the sterilization tank 20 detected by the pressure gauge 552 becomes 0.04 MPa or less, it is determined that the drainage is completed. When draining, a “drain” lamp (not shown) is lit (see FIG. 4).

  The aeration process is a process for ventilating the sterilization tank 20 and returning the pressure to normal pressure after the above-described drainage process. In the ventilation process, the motor-operated valve 525 in the sterilized drainage pipe 55 is opened after the drainage process, but the electromagnetic valve 522 in the second water supply pipe 51B is closed. During ventilation, a “vent” lamp (not shown) is lit (see FIG. 4).

  The seven-step drainage sterilization method described above is automatically executed by a control panel (not shown) of the drainage sterilizer 10. More specifically, the control panel includes a CPU (central processing unit) that performs a central function of various controls, a ROM that stores programs executed by the CPU and various fixed data, and temporary execution of the programs. The circuit is mainly composed of a RAM or the like for storing necessary data.

  The embodiments of the present invention have been described above with reference to the drawings. However, the specific configuration is not limited to the above-described embodiments, and the present invention can be changed or added without departing from the scope of the present invention. Included in the invention. For example, in order to grasp in advance the clogging of the strainer 572 provided in the experimental waste water suction pipe 53, a “clogging” lamp is equipped, and the “clogging” lamp is turned on when the strainer 572 starts to clog. You may control so that it may.

  In addition, an overcurrent relay, heater limiter, etc. are attached as safety devices in the drainage sterilizer 10, and when an abnormality occurs in the equipment, the safety device is operated to perform necessary measures and simultaneously display an error code. May be configured to display an abnormality and sound a buzzer.

It is a conceptual diagram which shows the waste water sterilizer which concerns on one embodiment of this invention. It is a perspective view showing typically the principal part of the drainage sterilizer concerning one embodiment of the present invention. It is a front view showing the appearance of the principal part of the drainage sterilizer concerning one embodiment of the present invention. It is a flowchart for demonstrating the waste water sterilization method which concerns on one embodiment of this invention. It is a graph which shows the correlation with the temperature of the experiment waste_water | drain, and progress of time in the waste water sterilizer which concerns on one embodiment of this invention. It is a conceptual diagram for demonstrating the path | route of the suction process in the waste water sterilization method which concerns on one embodiment of this invention. It is a conceptual diagram for demonstrating the path | route of the vacuum process in the waste water sterilization method which concerns on one embodiment of this invention. It is a conceptual diagram for demonstrating the path | route of the drainage process in the drainage sterilization method which concerns on one embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Experimental drainage tank 2 ... Drainage tank 10 ... Drainage sterilizer 20 ... Sterilization tank 21 ... Water level sensor 22 ... Water level sensor 23 ... Temperature sensor 30 ... Electric heater 40 ... Vacuum pump 51 ... Water supply pipe 51A ... First water supply pipe 51B ... Second water supply pipe 52 ... Vacuum pump intake pipe 53 ... Experimental waste water suction pipe 54 ... Vacuum pump drain pipe 55 ... Sterilized drain pipe 56 ... Experimental drain return pipe 57 ... Safety valve relief pipe 501 ... Mixed valve 511 ... Manual valve 512 ... Manual valve 513 ... Manual valve 514 ... Manual valve 521 ... Solenoid valve 522 ... Solenoid valve 523 ... Solenoid valve 524 ... Solenoid valve 525 ... Solenoid valve 531 ... Check valve 532 ... Check valve 551 ... Pressure gauge 552 ... Pressure gauge 561 ... Pressure switch 562 ... Pressure switch 563 ... Pressure switch 564 ... Pressure switch 571 ... Strainer 572 ... Strainer 573 ... Strainer 581 ... Temperature sensor

Claims (7)

In the wastewater sterilizer for sterilizing the wastewater to be treated supplied in a sealed tank by heating means,
Pressure changing means for changing the pressure in the tank;
After the temperature of the wastewater to be treated rises due to the operation of the heating means and the pressure in the tank reaches a predetermined value or more, the pressure in the tank is temporarily reduced by the operation of the pressure changing means to change to the pressure in the tank. A drainage sterilizer characterized by forcibly generating convection in the wastewater to be treated.   When the temperature of the wastewater to be treated rises due to the operation of the heating means and the pressure in the tank exceeds a predetermined value, the operation of the pressure changing means is stopped after the operation of the heating means is temporarily stopped and a predetermined time has elapsed. By temporarily reducing the pressure in the tank to change the pressure in the tank, forcibly generating convection in the wastewater to be treated, stopping the operation of the pressure changing means, and then again heating the means The drainage sterilization apparatus according to claim 1, wherein the wastewater to be treated is heated to a predetermined temperature by operating the. It has a vacuum pump for vacuuming the treated wastewater stored in the drainage tank and sending it into the tank,
The drainage sterilizer according to claim 1 or 2, wherein the vacuum pump is also used as the pressure changing means. The vacuum pump is composed of a casing and an impeller rotatably disposed therein, and a water seal capable of continuous suction by introducing a sealing liquid into the casing and rotating the impeller. A vacuum pump,
The drainage sterilization apparatus according to claim 3, wherein when discharging the sealing liquid mixed with the air sucked from the tank in the casing, the sealing liquid is introduced into the drainage tank without passing through a filter. The upstream end side of the drainage pipe is introduced into the tank so as to extend from the upper part toward the bottom, and the downstream end side of the drainage pipe opens at a position lower than the opening on the upstream end side. Arranged in
The wastewater sterilization apparatus according to claim 1, 2, 3, or 4, wherein the wastewater to be treated that has been sterilized in the tank is discharged out of the tank by the siphon principle through the drainage pipe.   The drainage sterilization apparatus according to claim 5, wherein when the drainage pipe is filled with sterilized wastewater to start the siphon, the pressure in the tank is used. In the wastewater sterilization method for sterilizing the wastewater to be treated supplied in a sealed tank by heating means,
A suction step, a temperature raising step, a sterilization step, and a drainage step,
The suction step is a step of sucking the treated wastewater stored in the drainage tank into the tank by vacuum suction by the operation of a vacuum pump,
In the temperature raising step, when the temperature of the wastewater to be treated rises due to the operation of the heating means and the pressure in the tank reaches a predetermined value or more, the operation of the heating means is temporarily stopped and a predetermined time has elapsed, By temporarily depressurizing the inside of the tank by the operation of the vacuum pump and changing the pressure in the tank, forcibly generating convection in the wastewater to be treated, and after stopping the operation of the vacuum pump, The step of operating the heating means again to raise the temperature of the wastewater to be treated to a predetermined temperature,
The sterilization step is a step of sterilizing the wastewater to be treated while maintaining the predetermined temperature,
In the drainage step, drainage is disposed in the tank so that the upstream end side is introduced so as to extend from the upper part toward the bottom, and the downstream end side is opened at a position lower than the opening part on the upstream end side. When the wastewater to be sterilized in the tank is discharged out of the tank by the siphon principle by the piping for use in the tank, and when the wastewater to be sterilized is filled in the drainage piping to start the siphon, A drainage sterilization method characterized by being a process using the pressure of

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