DE10112719A1 - Modular reverse osmosis water treatment assembly has regulator varying water output in accordance with demand - Google Patents

Abstract

A modular (10,11) reverse osmosis water treatment assembly has a water inlet (13) with a concentrate outlet (14) and a treated water outlet (15). Water is supplied to the treatment module by a pump (16) with especially a regulator (9) which maintains the water pressure at a level proportional to the water outlet pressure. Water outlet pressure can be adapted in accordance with consumer demand. The pressure regulator has a frequency converter regulating pump pressure in the range 1 to 80 bar. The outlet pressure is monitored by a sensor (24). Water hardness is monitored (1) at the inlet (12). The supply of incoming water is stopped if hardness exceeds a given value. The modules may be operated jointly or separately.

Description

The invention relates to a reverse osmosis system according to the preamble of the patent claim 1.

A reverse osmosis process enables water to be almost completely desalinated. The main advantage of this process is the low environmental impact. For the This process does not require any chemicals.

The water desalinated in this way is used especially in industry, pharmacy and used in hospitals. Also for air humidification in ventilation and air conditioning water is often used in this way. Can continue Reverse osmosis systems can be used for the treatment of sea water. Sea water is unsuitable for drinking because of its high salt content. With the help of a Reverse osmosis system, the salinity of sea water can be reduced to the extent that it is suitable as drinking water. Such facilities are particularly in coastal areas regions with little or no fresh water resources.

A reverse osmosis system is known from the prior art, the softener is connected upstream. In this water softening system, raw water is reduced decalcified as 1 ° dH. The exit of the water softener is with the entrance of the order reverse osmosis system coupled. At the entrance, the reverse osmosis system has a Pump up the softened water at a pressure of about 10 bar to 80 bar presses through modules. The actual reverse osmosis process takes place in the modules instead of pressing the water against semi-permeable membrane with pressure. Salts and / or minerals are filtered out, with the raw water in one Permeate (diluate) and a concentrate split. The permeate (diluate) is special Low salt water can still be used. The concentrate is and will be a waste product discarded. Usually a module produces about 75% permeate (diluate) and 25% Concentrate. The pump pressure as well as the permeate and concentrate quantity are manual adjustable. The permeate is stored in a pressureless container and from there on pumped on to an end user.  

This conventional reverse osmosis system has the disadvantage that the water in the Container can germinate. This is particularly due to the fact that the container ter is never completely sealed and the water often remains in the container for a long time. Heating the water in the tank, especially in summer, will Germination also promoted. To prevent contamination, UV Lamps, chemicals or additional lines are used, but this is energy effort, the environmental impact and the design effort increased.

Another significant disadvantage is the switch-on phase of the reverse osmosis Plant causes. During this switch-on phase, the water is much higher ren conductance, about 150 to 200 µS / cm, as desired. Furthermore, the conventional one Reverse osmosis system requires a relatively large amount of space. Finally, the manual setting of important sizes results in undesired inaccuracies.

It is an object of the invention to provide a reverse osmosis system, which overcomes the disadvantages mentioned above.

This object is achieved by the subject matter according to claim 1.

According to the invention it is provided that a pressure control device is provided on the pump or between the pump and raw water inlet, which adjusts a raw water pressure P _R as a function of a predetermined diluate pressure P _D at the diluate outlet. As a result of this measure, only as much raw water is supplied in at least one module as a corresponding amount of low-salt diluate is required at the diluate outlet. So no excess diluate is produced. Therefore, no container is required in which the diluate can germinate. A booster pump is also not required, since the required pressure is already provided by the pump which is connected upstream of the module. By eliminating the container and the booster pump, the design effort of the entire system is also reduced.

In particular, it can be provided that the pressure control device has a Frequency converter for controlling the pump includes such that the pump over a continuous pressure range, in particular from 10-80 bar, can be set. The Use of the frequency converter enables lossless control. The The pump is only supplied with the energy that is actually required. It will no excess energy is converted into heat.  

Furthermore, it can be provided that a pressure sensor is provided on the diluate line system arranged at the diluate outlet for detecting the diluate pressure P _D. Placing the pressure sensor in this way enables particularly precise pressure detection. In the diluate line system in particular, the flow is essentially laminar, so that measurement errors remain very small.

In addition, it can also be provided that, in addition to the diluate pressure P _D, the raw water pressure Pn present at the raw water inlet is taken into account to control the pump by means of the pressure control device. As a result, the pressure control device can also react to fluctuations in the raw water pressure P _R. In this way, the pressure at the outlet of the pump is set particularly precisely.

Finally, a concentrate return can be provided to the concentrate all or part of the concentrate that escapes through the reverse osmosis Module. Through this measure, the regulatory options of the ge entire plant increased. In particular, the electrical conductance of diluate and Kon be adjusted according to the requirements.

It can be provided that the concentrate return comprises a return valve which, depending on the desired amount of diluate and / or the ion concentration I _{C of} the diluate, conducts a certain part of the concentrate through the concentrate return. As a result, the ion concentration I _C can also be set to a constant value.

Further features, advantages and refinements of the invention are the subject of Dependent claims.

A preferred embodiment of the invention is described below with reference to the attached drawing explained in more detail.

The single figure shows a block diagram of the preferred embodiment of the Reverse osmosis system according to the invention.

The reverse osmosis system has an input 12 . A hardness degree monitoring device 1 , a first pressure sensor 2 , a filter 3 , a second pressure sensor 4 , a solenoid valve 26 , a pressure switch 5 and a pump 16 are connected in series to this input 12 . A third pressure sensor 6 is assigned to the output of the pump 16 . The pump 16 also has a control input which is coupled to a frequency converter 9 . The output of the pump is coupled to a raw water inlet 13 of two reverse osmosis modules 10 and 11 connected in parallel. The reverse osmosis modules 10 and 11 also have a concentrate outlet 14 and a diluate outlet 15 . A control valve 8 is connected downstream of the concentrate outlet 14 . The control valve 8 has two outputs. One output of the control valve 8 is connected via a return line 20 to the coupling point of the pressure switch 5 and the solenoid valve 26 . The other outlet of the control valve 8 is connected to a concentrate drain 18 via a water meter 7 . The diluate outlet 15 is followed by a tap 21 , a first conductivity sensor 23 , a second water meter 22 , a second conductivity sensor 28 , a fourth pressure sensor 24 and a diluate outlet 25 , which are connected via a diluate line system 19 . The diluate line system 19 is connected to the outlet of the pump 16 via a bridging line 29 . The bypass line 29 has a second control valve 27 .

Raw water, which has usually been decalcified in a softening system, is fed to the reverse osmosis system via input 12 . The degree of hardness monitoring device 1 is provided to detect the degree of hardness of the raw water, so that if a predetermined limit value is exceeded, the further supply of raw water can be prevented automatically or manually, for example by closing the solenoid valve 26 . If the value exceeds 1 ° dH, the reverse osmosis system is preferably switched off automatically. In this way it is prevented that water with a higher degree of hardness gets into the reverse osmosis modules 10 and 11 . This would have the consequence that the reverse osmosis modules 10 and 11 would be blocked, and ultimately the entire reverse osmosis system would fail. By using the hardness level monitoring device 1 , the total maintenance effort of the system is considerably reduced. The solenoid valve 26 can be closed when the system is switched off, for example to enable the system to be flushed.

The pump 16 is intended to press the raw water into the reverse osmosis modules 10 and 11 with pressure, usually between 10 and 80 bar. The pump 16 is controlled by the frequency converter 9 . A DDC controller is preferably connected upstream of the frequency converter 9 . The pressure at the outlet of the pump 16 is regulated as a function of those values which are detected by the third pressure sensor 6 , the second water meter 22 , the conductivity sensor 23 and the fourth pressure sensor 24 . In this way, the pump 16 is regulated in such a way that as much raw water is supplied to the reverse osmosis modules 10 and 11 as the diluate at the diluate drain 25 is required by an end user. Intermediate storage of the diluate in a container or the like is not necessary. This prevents nucleation, which often occurs in such containers. The reverse osmosis modules 10 and 11 can preferably be switched on and off separately. In this way, the entire system can be controlled depending on the required amount of diluate, especially in the case of even more modules.

The control valve 8 is designed as a 2-way valve. The control valve 8 can be used to set which proportion of the concentrate is returned to the flow of the pump 16 via the return line 20 . For example, the control valve 8 can be controlled by a DDC controller. The remaining portion of the concentrate is fed to the concentrate drain 18 via the first water meter 7 . The concentrate fed to the concentrate drain 18 is usually discarded as waste. The adjustable return of the concentrate increases the control options for the entire reverse osmosis system. In particular, the concentrate is thereby continuously adjustable.

In the embodiment described here, the bypass line 29 and the second control valve 27 form part of a blending device. As a result, the reverse osmosis modules 10 and 11 are bridged in particular, so that part of the filtered raw water can be fed directly to the diluate line system 19 and the diluate drain 25 . This provides a further control option for the reverse osmosis system. Part of the filtered raw water can thus be fed past the two reverse osmosis modules 10 and 11 past the diluate drain 25 if the end user tolerates a corresponding predetermined salt content. The current conductance of the blended diluate is preferably detected by the second conductance sensor 28 . Depending on the salinity tolerated by the end user, the ratio of the diluate flow output from the reverse osmosis modules 10 and 11 and the filtered raw water led through the bypass line 29 can then be adjusted manually or automatically by means of the control valve 27 . Furthermore, it may be advantageous additionally to detect the current conductance of the from the reverse osmosis modules 10 and 11 diluate issued before the intersection with filtered raw water in the first conductance 23rd The regulation can be improved because the quality of the diluate output from the reverse osmosis modules 10 and 11 can be used to estimate the presumably possible addition of filtered raw water via the bypass line 29 . A check can then still be carried out by determining the conductance of the blended diluate in the second conductance sensor 28 . This method is particularly economical because the two reverse osmosis modules 10 and 11 do not convey more water than is necessary. This has a favorable effect on the maintenance intervals of the reverse osmosis modules 10 and 11 .

The blending device creates a further possibility of optimally adapting the structural and technological outlay for the reverse osmosis system to the respective requirements. The bypass line 29 and the second control valve 27 are inexpensive components which also require little maintenance. Due to the blending device, the flow rate of the two reverse osmosis modules 10 and 11 can be significantly lower than that of the entire reverse osmosis system.

In particular, it is provided that the reverse osmosis system can be coupled to an EDP system. The recorded measured values of all sensors are fed to the EDP system. On the basis of these measured values, the frequency converter 9 and the control valve 8 are controlled by the EDP system. In this way, constant monitoring of the reverse osmosis system is possible using the computer system. A display of the EDP system is provided for the permanent optical monitoring of the most important measurement data. A permanent recording of the measured values is also provided. The computer system can be implemented inexpensively using a PC. For example, a PLC control can also be used. All data and any faults can be forwarded to a control center immediately and immediately. Furthermore, it should be noted that the system according to the invention takes up very little space. Finally, with this system, the DIN 6022 relevant for nucleation can be easily complied with. DIN 2000, which is relevant according to the Drinking Water Ordinance and also relates to nucleation, can also be met with the reverse osmosis system according to the invention.

The reverse osmosis system according to the invention can be used in industry. For numerous manufacturing processes and products, water with a low Salinity needed. For the pharmaceutical industry in particular, this reverse osmosis  System advantageously suitable. In addition to the extremely low salt content, the Nucleation very low, which is particularly important for pharmaceutical products. The reverse osmosis system according to the invention can also be used in hospitals are used where the low nucleation in addition to the low Salinity plays an important role. Finally, the invention Reverse osmosis system can be used as a seawater treatment system, so that drinking water can be obtained in this way. In coastal areas that only low fresh water occurrence, the reverse osmosis according to the invention Plant can be used particularly efficiently for the provision of drinking water.  

LIST OF REFERENCE NUMBERS

1

Hardness monitoring device

2

First pressure sensor

3

filter

4

Second pressure sensor

5

pressure switch
G Third pressure sensor

7

First water meter

8th

First control valve

9

frequency converter

10

Reverse osmosis module

11

Reverse osmosis module

12

entrance

13

raw water input

14

concentrate output

15

Diluatausgang

16

pump

18

concentrate drain

19

Diluatleitungssystem

20

Return line

21

tap

22

Second water meter

23

First conductivity sensor

24

Fourth pressure sensor

25

Diluatabfluß

26

magnetic valve

27

Second control valve

28

Second conductivity sensor

29

bypass line

Claims (9)

1. Reverse osmosis system for raw water, in particular city or well water, for the extraction of low-salt diluate or permeate, comprising

• - At least one reverse osmosis module ( 10 , 11 ) with a raw water inlet ( 13 ), a concentrate outlet ( 14 ) and a diluate outlet ( 15 ) and
• - a pump ( 16 ) which applies the raw water to the reverse osmosis modules ( 10 , 11 ),

characterized in that
on the pump ( 16 ) or between the pump ( 16 ) and raw water inlet ( 13 ) a pressure control device ( 9 ) is provided, which sets a raw water pressure P _R as a function of a predetermined diluate pressure P _D at the diluate outlet ( 15 ), the predetermined one Diluate pressure P _{D can be} adapted to the requirements of downstream consumers. 2. Reverse osmosis system according to claim 1, characterized in that the pressure control device comprises a frequency converter ( 9 ) for controlling the pump ( 16 ), such that the pump ( 16 ) over a continuous pressure range, in particular from 10 to 80 bar adjustable is. 3. Reverse osmosis system according to claim 1 or 2, characterized in that a pressure sensor ( 24 ) is provided on the diluate outlet ( 15 ) or on a downstream side of the diluate outlet ( 15 ) arranged diluate line system ( 19 ) for detecting the dllate pressure P _D , 4. Reverse osmosis system according to one of claims 1 to 3, characterized in that for controlling the pump ( 16 ) by means of the pressure control device, in addition to the diluate pressure P _D, the raw water pressure P _R present at the raw water inlet ( 13 ) is taken into account. 5. Reverse osmosis system according to one of claims 1 to 5, characterized in that the reverse osmosis system at the entrance ( 12 ) has a degree of hardness monitoring device ( 1 ) to stop the supply of raw water when a predetermined degree of hardness is exceeded. 6. Reverse osmosis system according to one of claims 1 to 5, characterized in that the reverse osmosis modules ( 10 , 11 ) can be switched on and off separately. 7. Reverse osmosis system according to one of claims 1 to 6, characterized in that a concentrate return ( 20 ) is provided in order to completely or partially pass the concentrate emerging at the concentrate outlet ( 14 ) through the reverse osmosis module ( 10 , 11 ) , 8. Reverse osmosis system according to claim 7, characterized in that the concentrate return ( 20 ) comprises a control valve ( 8 ) which, depending on the quantity of diluate requested by the end user and / or on the ion concentration I _C in the diluate, reaches a certain partial amount of the Concentrate through the concentrate return ( 20 ) passes. 9. reverse osmosis system according to one of claims 1 to 8, characterized in that the reverse osmosis system comprises a bypass line ( 29 ) with a second control valve ( 27 ), which between the outlet of the pump ( 16 ) and the di-luat- Line system ( 19 ) is switched.