DE10113278A1 - Pressure die-casting wash water purification involves reverse osmosis and membrane filtration to separate acrylates and methacrylates before ecologically acceptable directing to public drainage system - Google Patents

Abstract

Plant involved feeds (1) the wash water to container (2) whence circulating pump (4) and membrane filter (6) receive the water via coarse filter (5). The filter (6) permeate is led off the drainage system and the concentrate for the sealing process concerned (9). The membrane filter is pressure-tightly coiled in plastics with temperature feeler (10) and/or manometer (11) and/or volumetric flowmeter (12,13) incorporated downstream. The wash water is subjected to reverse osmosis to allow the permeate to be directed into the public drainage system or re-used, with the concentrate itself used for the sealing process.

Description

The present invention relates to a method for the treatment of wash water from die-cast Impregnation according to the preamble of claim 1 and on a device for performing the method.

According to the state of the art, die casting is used process for aluminum and magnesium alloys provides, for example, used in gearboxes become. Such castings often have a partially pori structure, which means that it therefore faces rivers liquids are leaking, especially with gearbox housings towards oil. These leaks are only partially then recognizable when the surface of the castings at the mechanical processing are cut.

In the majority of cases, leaky castings can occur be subsequently sealed. In this context there is a preparatory step before the actual sealing process supply, then the parts in a vacuum chamber brought, which then with the vacuum build-up liquid resin is flooded. So the pores suck and capillary of the workpiece to be machined with the resin full. After draining the resin from the casting surface, there is a spin cycle of rough removal of the resin from the casting surface. For thorough Chen cleaning the casting are part of the actual Chen washing process wash water used.  

The casting is then heated to approx. 90 ° C warms, causing an exothermic curing process of the resin is initiated at about 150 ° C to 170 ° C, so that Cast part sufficient for the intended stress is tight. The curing is irreversible.

Commercial Acry are used as sealing media latex, methacrylates and methacrylate esters with the usual Concentrations of approximately 1% by weight are used are partly soluble in the washing water and partly emul yaw. The washing water is more or less today successful sewage treatment in the sewage system left, which from the point of view of environmental pollution is peaceful. The latter is particularly evident in the measurement worth for the so-called chemical oxygen demand COD, its limit for an introduction to the public Sewerage network of authorities and municipalities different is handled.

According to the state of the art nowadays different processes used for wastewater treatment.

One possibility is that of coalescence filtration components not dissolved in water; here are in generated essentially from the smallest drops larger and the then filtered out.

Another known solution is washing boil water, with flocculation of the resin, whereby the dissolved monomeric components are incomplete fail so that the COD Value.  

In this context is also a precipitation and flo chemical additives have been proposed; in view of the high organic content, however the success of this method can be classified as moderate.

The same also applies to distillation processes Wastewater treatment because they have the disadvantage of great effort only vapor phase soluble components to remove.

Accordingly, it becomes clear that none of the ver driving is fully suitable, adequately prepared Wash water to be fed into the public sewage system or suitable material flows for a closed cycle economy (wash water and separate resin return winnung), whereby the indirect Introductory ordinance, regulations of municipalities and other criteria for channel discharge are taken into account.

Micro or ultrafiltration processes are not ge apt to solve the problem; Nanofiltration process ha have proven to be more successful, but they can do a lot small molecules of the water-soluble resin components only partially withhold.

The present invention is based on the object a process for the treatment of washing water from the Die-cast impregnation to indicate which is sufficient Treatment of the washing water used is guaranteed.  

In particular, the inventive method should to reduce the previous significant COD burden so far that an introduction of the wastewater (permeate) into the public Sewerage or reuse of both Water for further washing processes, as well as the concentra is made possible for the sealing process.

Furthermore, a device for carrying out of the procedure.

In addition, the process should be inexpensive and space-saving be feasible.

This task is for a procedure through the Merkma le of claim 1 and for a device by the Features of claim 10 solved. Further design cations and variants emerge from the subclaims.

Accordingly, a reverse osmosis process is proposed with a highly restrained diffusion membrane and spec properties that block the Prevent membrane surface during the actual osmosis process dert, preferably from a single-stage reverse osmosis Use is made.

The membrane technology guarantees satisfaction separating the impregnating agent components "Acrylates" or "methacrylates" and "methacrylate esters".

The method according to the invention is simple, special for an application outside the chemical industry without Specialist staff suitable as well as inexpensive and space-saving. It also doesn't become environmentally critical  Waste generated and no additional chemicals in the measuring method used to monitor the system.

The following is the method according to the invention with reference to the accompanying figure, which is a schematic Dar position of an embodiment of a device for Implementation of the method shows, explained in more detail.

Through the inlet 1 , the contaminated washing water flows into a container 2 for batchwise (batchwise) preparation. The container 2 has a level control and is preferably made of stainless steel.

As shown in the figure, level switches 3 can be provided for level control.

The wash water is then passed on from the tank 2 via pumps 4 , 4 'and coarse filter 5 to the membrane filter unit 6 . The pumps are a circulation pump 4 and a form pump 4 '; As a Grobfil ter to protect the reverse osmosis station in the membrane filter ter unit 6 , a candle filter 5 is provided. The permeate of the membrane filter goes back through an outlet in the washing circuit 7 or, if necessary, into the sewer system 8 , the recovered concentrate (resins) via a further outlet for further use 9 (sealing device) or, if necessary, for a repeated run through the cleaning section.

The membrane block used for reverse osmosis of the membrane filter unit 6 consists of pressure-resistant Wickelmodu len, the pressure build-up and the required overflow takes place by means of a pump 4 'already mentioned.

The membrane is a high retention diffusion membrane with specific properties, so that a blockage of the membrane surface at the actual Chen osmosis process is prevented.

Preferably, the effective effective membrane area is approximately 11 m ² , which can be dimensioned as required; the membrane is preferably made of synthetic polymer.

Furthermore, measuring, control and regulating devices are provided which detect the pressure, the volume flow and the temperature. For example, within the scope of the embodiment shown in the figure, a temperature measuring device 10 , a pressure gauge 11 and a floating flow meter 12 and an induction flow meter 13 are provided.

In the low pressure area, the pipes are made of PVC, whereas in the high pressure area, preferably stainless steel is used.

In a variant of the present invention, cooling of the circulating contaminated washing water is provided. For this purpose, a heat exchanger 14 is used ver.

reference numeral

1

Intake

2

container

3

level switch

4

Circulation pump,

4

'' Pre-pressure pump

5

Candle filter

6

Membrane filter unit

7

Wash cycle

8th

sewerage

9

Re-use branch

10

Temperature measuring device

11

manometer

12

Schwebedurchflußmesser

13

Electromagnetic flowmeters

14

heat exchangers

Claims (16)

1.Process for the treatment of wash water from die-cast impregnation and in particular for the separation of impregnating agent components such as acrylates or methacrylates, characterized in that the wash water to be treated is treated by means of reverse osmosis in such a way that the waste water (permeate) is discharged into the public sewage system or Reuse of both the water for further washing processes and the concentrate for the sealing process is made possible. 2. Process for the treatment of wash water from the Die-cast impregnation according to claim 1, characterized ge indicates that the wash water is by means of single or multi-stage reverse osmosis is processed. 3. Process for the treatment of wash water from the Die-cast impregnation according to claim 1 or 2, therefore characterized that a highly reserved Diffusion membrane is used, blocking the membrane surface during the actual osmosis process is prevented. 4. Process for the treatment of wash water from the Die-cast impregnation according to one of the preceding claims che, characterized in that a Prefiltration is provided to protect the reverse osmosis station is.   5. Process for the treatment of wash water from the Die-cast impregnation according to one of the preceding claims che, characterized in that the Wash water is processed in batches. 6. Process for the treatment of wash water from the Die-cast impregnation according to one of the preceding claims che, characterized in that the Pressure build-up for the purpose of reverse osmosis and the required che overflow by means of a high pressure pump. 7. Process for the treatment of washing water from the Die-cast impregnation according to one of the preceding claims che, characterized in that a Cooling of the circulating contaminated wash water vorese hen is. 8. A process for the treatment of wash water from die-casting impregnation according to one of the preceding claims, with the following steps:

• - Inflow of the contaminated washing water through an inlet ( 1 ) in a container ( 2 ) for batches of preparation;
• - Forwarding the washing water from the container ( 2 ) via pumps ( 4 , 4 ') and coarse filter ( 5 ) to a membrane filter tereinheit ( 6 );
• - Treatment of the washing water in the membrane filter unit ( 6 );
• - Return the permeate of the membrane filter unit ( 6 ) in the washing circuit ( 7 ) or forward to the Ka nalisation ( 8 ) and
• - Forwarding the concentrate obtained for further use to a sealing device ( 9 ) or to the cleaning section for a repeated run.

9. A method for treating wash water from die-casting impregnation according to one of the preceding claims, characterized in that measuring, control and regulating devices ( 10 , 11 , 12 , 13 ) are provided which detect the pressure, the volume flow and the temperature , 10. Device for performing the method according to one of claims 1 to 9, characterized in that it contains an inlet ( 1 ) for the wash water and a container ( 2 ) for batch processing of the wash water, a circulation pump ( 4 ) , a coarse filter unit ( 5 ), a pre-pressure pump ( 4 ') and a membrane filter unit ( 6 ) are provided such that the washing water via the circulation pump ( 4 ), the coarse filter unit ( 5 ) and the pre-pressure pump ( 4 ') Processing can be forwarded to the membrane filter unit ( 6 ) and a first outlet for the per meat of the membrane filter unit ( 6 ) for forwarding the permeates into the sewage system or into the washing circuit and a second outlet for forwarding the concentrate to the cleaning section or to one Sealing device ( 9 ) is provided. 11. The device according to claim 10, characterized thereby that the membrane filter unit ( 6 ) consists of pressure-resistant winding modules. 12. The apparatus of claim 10 or 11, characterized characterized that the membrane from syn synthetic polymer is produced. 13. Device according to one of claims 10 to 12, characterized in that a temperature measuring device ( 10 ) and / or a manometer ( 11 ) and / or at least one device for measuring the volume flow ( 12 , 13 ) are provided. 14. Device according to one of claims 10 to 13, characterized in that a heat exchanger ( 14 ) is provided. 15. The device according to one of claims 10 to 14, characterized in that the Rohrlei in the low pressure area made of PVC and in the high pressure area are richly made of stainless steel. 16. Device according to one of claims 10 to 15, characterized in that the container ter ( 2 ) has a level control, level switch ter ( 3 ) being provided.