JP2008253958A - Method and apparatus for treating drain water by using negative pressure generating means - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for treating drain water from an oil separation apparatus, wherein the inexpensive and compact apparatus is used while sending drain water actively. <P>SOLUTION: The apparatus for treating drain water is composed of a pretreatment tank opened to the atmosphere, a water level-determining means and an airtight posttreatment tank. The posttreatment tank has: a drain water inlet, which is connected to an upstream-side pipeline through a drain check valve, at the lower part thereof; a drain water outlet, which is connected to a downstream-side pipeline through a check valve, on the upper side surface thereof; and a negative pressure generating means, which generates negative pressure according to the determination of the water level judgement means, at the uppermost part thereof. The negative pressure generating means is controlled by an air pressure control circuit according to the water level judgement. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for treating drain water discharged from a compressor or the like, and more particularly, to a treatment method and a drain water treatment device suitable when an inexpensive and compact device is required.

  In the drain treatment apparatus, it is necessary to purify the drain water from the drain generation source to a water quality that can be drained by passing it through devices such as an adsorption treatment tank and an electrolytic treatment tank. In the drain water treatment apparatus currently used, as a drain water feeding means, a method such as pressure feeding with compressed air, flowing down due to a water head difference, water feeding with an electric pump is used.

  In the method using the compressed air directly, the drain water is jetted together with the compressed air in the main pipe when the drain trap is operated, so that the drain water is directly used to pump the drain water. This method does not require a power supply and has a high degree of freedom in design. However, it is necessary to consider the safety of each part structure to handle the pressure (internal pressure) of the drain pipe, and there is a drawback that the cost increases. .

  In the method using the water head difference, the discharged drain water is temporarily stored and released to the atmosphere, then guided to a piping system below the storage tank, and the drain water is sent using its own weight. In this method, the power is not used and the internal pressure does not increase, so the structure is simple.However, the arrangement of the equipment is restricted, and the drain water in the piping cannot be forcibly cleared, so it cannot cope with clogging of the adsorbent. There is a problem.

  Therefore, as another method, there is a method in which the discharged drain water is once released into the atmosphere and then actively pressurized and fed using an electric pump. This method is rational because it can pressurize only the necessary parts, but because electricity is used for water supply, it costs money for safety measures such as electric leakage as well as power, and when adsorbents are clogged There are problems such as the possibility of seizing the pump during idling. Therefore, each method had advantages and disadvantages, and none was decisive.

In the invention described in Japanese Patent Application Laid-Open No. 2001-17961, a pressure feeding unit is connected between two open check valves between a pre-treatment tank open to the atmosphere and a sealed post-treatment tank. It is connected to a solenoid valve that can be switched between pressurized air from the pipe and atmospheric pressure. The drain water ejected by the operation of the drain trap is once introduced into a pretreatment tank that is open to the atmosphere, and after impurities are roughly removed, it enters the pressure feeding unit from its lower end by its own weight. When the water level in the pumping unit reaches a predetermined height, the solenoid valve connected to the main pipe opens several times by the action of the float switch in the pumping unit, and the drain water is intermittently placed at the subsequent stage by the pressure to the post-treatment tank. It is fed, the necessary post-processing is performed, and it is discharged as purified water. This method performs active pressurized water supply as with an electric pump, so an open-air treatment tank can be used in the previous stage, and a stirring effect by pressurized air can be expected. Has features such as low price.
JP 2001-17961 A

  The technology described in Patent Document 1 has various advantages and is sufficiently satisfactory depending on the purpose of installation, but the post-treatment tank is subject to internal pressure, and thus a large and expensive container must be used. This has been a problem under use conditions where an inexpensive and compact device is required. Accordingly, an object of the present invention is to provide a method for treating a drain water of an oil / water separator so that a more inexpensive and compact apparatus can be used while actively draining water.

  In the first aspect of the present application, in the drain water treatment using the adsorption treatment tank, the drain water once released to the atmosphere is introduced into the adsorption treatment tank filled with the adsorbent, and the negative water is discharged from the downstream side of the adsorbent. The above problem is solved by a drain water treatment method in which drain water is fed by being sucked by a pressure generating means. Although it is common to use a pressurizing means for the forced water supply of drain water, in order to eliminate the problems such as an increase in the size of the pressure vessel in the conventional treatment method, a new method of suctioning with the negative pressure generating means is used. The configuration is adopted. An optimum processing method is provided when a particularly inexpensive and compact apparatus is required depending on use conditions.

  The invention according to claim 2 of the present application is the drain water treatment method according to claim 1, wherein the negative pressure generating means is an ejector in which the primary flow side (main air) is connected to the compressed air pipe. By generating negative pressure with the ejector, it is possible to supply drainage using the compressed air of the main pipe without using an electric pump, etc., and to realize an environmentally friendly and non-powered device it can.

  The invention according to claim 3 of the present application is the drain water treatment method according to claim 1 or 2, wherein the water pressure determination means is provided in the front stage of the adsorption treatment tank, and the negative pressure is obtained when the upstream water level is equal to or lower than the set water level. The generating means is operated. Energy saving is further improved by performing forced water supply only when a certain amount or more of drain water is stored in the previous stage.

  Invention of Claim 4 of this application is comprised from the pre-processing tank open | released to air | atmosphere, a water level determination means, and a closed-type post-processing tank, and the said post-processing tank is via a drain check valve in the lower part. It has a drain water inlet connected to the upstream pipe, and has a drain water outlet connected to the downstream pipe via a check valve on the upper side, and generates negative pressure at the top according to the judgment of the water level judgment means The above problem is solved by a drain water treatment device in which negative pressure generating means is installed. The present invention performs a two-stage process with a pre-treatment tank and a post-treatment tank, but a negative pressure generating means is provided at the top of the post-treatment tank to force the drain water flowing from the lower drain water inlet. In particular, the drain water treatment method according to claim 3 is rationally realized by raising the temperature and discharging it from the upper drain water outlet. Check valves provided at the drain water inlet and outlet prevent the back flow of drain water.

  More preferably, a device without a power source is realized by controlling the negative pressure generating unit based on the water level determination by a pneumatic control unit without a power source. A branch pipe is branched from the middle part of the front and rear treatment tanks, an open water surface is provided and a float switch is installed. The float is connected to a mechanical valve that switches an input signal of an air operated valve, which will be described later, between a pressurizing side and an atmospheric pressure side. When the float exceeds the specified height, the mechanical valve is activated to send an actuation signal to the air actuated valve. The air actuated valve switches the primary side of the ejector from the atmospheric pressure side to the pressurized side and supplies compressed air to the ejector. Generate pressure. The input signal of the air actuated valve is held for a certain time by a delay circuit provided therewith. Thus, a negative pressure can be generated at a predetermined timing without using an electrical control circuit.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory view showing an example of a drain treatment apparatus using the drain water treatment method of the present invention, in which a solid line represents a drain water pipe and a broken line represents an air pipe. In the figure, 1 is a pretreatment tank, 2 is a water level determination means, 3 is a post-treatment tank, and 4 is an air pressure control means.

  The pretreatment tank 1 of the present embodiment not only stores drain water, but also releases compressed air discharged from the compressor together with the drain water into the atmosphere, and adsorbs oil components originally contained as coarse oil particles in the drain water. It has the function to process by. The pretreatment tank 1 is composed of a cylindrical container 102 filled with a pretreatment adsorbent 101 suitable for rough oil removal, and the top of the container 102 is connected to a drain generation source of a compressed air pipe via a drain trap (not shown). A connected drain inlet 103 is provided. A part of the drain inlet 103 protrudes to the inside of the container, and a number of vent holes 104 are provided around the drain inlet 103. An overflow pipe 105 that discharges oil and the like floating on the liquid surface is connected to the upper side surface of the container 102, and a drain outlet 106 is provided on the lower side surface.

  The drain that flows in along with the compressed air from the drain inlet 103 is depressurized and separated into gas and liquid in the space above the pretreatment tank 1 that is open to the atmosphere, and only the liquid part flows under the pretreatment adsorbent 101 under its own weight. The oil is roughly removed. During this time, excess pressurized air is discharged from the vent 104 at the top of the container, and oil particles that have floated to the liquid surface due to the difference in specific gravity are discharged from the overflow pipe 105. The drain water that has passed through the adsorbent 101 is stored in the lower part of the container 102, and part of the drain water flows out from the drain outlet 106 to the water level determination means 2 and the post-treatment tank 3 due to water head pressure.

  From the drain pipe connected to the drain outlet 106 of the pretreatment tank 1, a drain valve V1 for drainage and a branch pipe to the water level determination means 2 are branched. The water level determination means 2 is composed of an enlarged diameter portion 201 at the tip of the upward branch pipe and a float 202 provided therein. The float 202 is connected to the mechanical valve 401 of the air pressure control means 4 and constitutes a float switch that operates when the drain water in the pretreatment tank 1 reaches a predetermined height. The drain main pipe further extends and is connected to the post-treatment tank 3 via a check valve V2.

  The post-treatment tank 3 includes a cylindrical container 302 filled with a post-treatment adsorbent 301 capable of adsorbing fine oil particles. A vacuum reservoir in which no adsorbent is disposed is provided at the top of the container 302, and a negative pressure side pipe of an ejector 403, which is a negative pressure generating means, is connected to the top. A drain inlet 303 is provided on the lower side surface of the container 302 and is connected to a drain main pipe via a check valve V2. Further, a drain outlet 304 is provided on the upper side surface, and is connected to the downstream pipe via a check valve V3.

  When the negative pressure generating means is activated, the inside of the vacuum reservoir is depressurized and becomes negative pressure with respect to the drain main pipe, so that drain water flows from the drain inlet 303 and rises inside the post-treatment adsorbent 301. During this time, the drain water is adsorbed with fine oil and purified to a water quality that can be drained. The treated water at a position exceeding the height of the drain outlet 304 flows out from the outlet 304 by the water head and is discharged from a discharge port (not shown). At this time, the check valve V2 at the drain inlet 303 prevents the drain water from flowing backward due to the head pressure when the negative pressure in the post-treatment tank 3 is released. The check valve V3 at the drain outlet 304 prevents air or drain water from flowing from the drain outlet when a negative pressure is supplied to the post-treatment tank 3.

  Next, the air pressure control means will be described. The mechanical valve 401 connected to the float 202 is connected to the compressed air piping and the PIL terminal of the air operating valve 402, and the input signal of the air operating valve 402 is switched between the pressure side and the atmospheric pressure side according to the operation of the float 202. The air operation valve 402 is connected to the compressed air piping and the ejector 403, and supplies or blocks compressed air (main air) to the primary side of the ejector 403 according to the PIL input signal. The ejector 403 generates negative pressure in the negative pressure side pipe connected to the post-treatment tank 3 when compressed air is supplied to the primary side. The time delay valve 404 and the check valve 405 act as a delay circuit for holding the input signal of the air operation valve 402 for a certain time.

  FIG. 2 is a time chart showing the operation timing of each part. When the float 202 exceeds a predetermined height due to accumulation of drain water, the mechanical valve 401 is activated to send an operation signal to the air operation valve 402, and the air operation valve 402 supplies compressed air to the primary side of the ejector 403. To generate negative pressure. When the negative pressure is supplied to the upper portion of the post-treatment tank 3, drain water will soon flow into the post-treatment tank 3 from the drain inlet 303, and the water level in the water level determination means 2 will drop, so the float 202 and the mechanical valve 402 The signal from the mechanical valve 401 is held by the check valve 405 before the PIL for a predetermined time set in the time delay valve 404, and compressed air is supplied from the air operating valve 403, The ejector 404 generates a negative pressure. During this time, the drain water remaining in the pretreatment tank 1 and the water level determination means 2 is also sent to the posttreatment tank 3.

  In the drain processing method and the drain processing apparatus of the present invention, components such as each processing system are designed with an external pressure, so that the apparatus can be made smaller and lighter than conventional internal pressure products, and there is no risk of rupture or the like. Therefore, it is also superior in terms of safety. Therefore, it is advantageous as an inexpensive and compact processing apparatus installed for each drain generation source. Moreover, since this apparatus is a non-powered apparatus, it is excellent in environmental consideration and has a great potential for use.

It is explanatory drawing which shows an example of the drain processing apparatus using the drain water processing method of this invention. It is a timing chart which shows the operation | movement order of each part of the apparatus of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pretreatment tank 101 Pretreatment adsorbent 102 Container 103 Drain inlet 104 Ventilation hole 105 Overflow pipe 106 Drain outlet 2 Water level judgment means 201 Expanded diameter 202 Float 3 Posttreatment tank 301 Posttreatment adsorbent 302 Container 303 Drain inlet 304 Drain outlet 4 Pneumatic control means 401 Mechanical valve 402 Air operated valve 403 Ejector 404 Time delay valve 405 Check valve

Claims (4)

In the drain water treatment using the adsorption treatment tank, the drain water once released to the atmosphere is introduced into the adsorption treatment tank filled with the adsorbent, and the drain water is sucked by the negative pressure generating means from the downstream side of the adsorbent. Treatment method of drain water to be fed. The drain water treatment method according to claim 1, wherein the negative pressure generating means is an ejector having a primary flow side connected to a compressed air pipe. The method for treating drain water according to claim 1 or 2, wherein a water level determination means is provided in a preceding stage of the adsorption treatment tank, and the negative pressure generation means is operated when the upstream water level is equal to or higher than a set water level. The pretreatment tank opened to the atmosphere, a water level determination means, and a sealed type posttreatment tank, the posttreatment tank has a drain water inlet connected to an upstream pipe via a drain check valve at the bottom. A drain having a drain water outlet connected to the downstream pipe via a check valve on the upper side surface, and a drain generating means for generating a negative pressure according to the determination of the water level determining means is installed at the top Water treatment equipment.

Images