GB2324975A - Intermittently moving belt filter - Google Patents

Abstract

In a gas pressurised, intermittently moving belt filter, a section of filter belt is supported on a perforated plate and sealed between a cover and a receptacle. Liquid to be filtered and pressurised gas are supplied above the filter belt, and filtrate is removed from below the filter belt. After filtration, rams (201) lift the cover away from the receptacle and the section of belt is moved out of the filter chamber by means of reversing motor 126. Flocculants and granular material may be added to form an electrically charged filter bed on top of the belt. Alternatively, lengths of disposable filter medium cut from rolls 112 may be laid on top of the belt. The belt may have portions (501, 502, 503) of different materials. The belt may be cleaned by passing it through a bath (901). The inside of the filter chamber may be cleaned by rotating manifolds (125) or by nozzles 710 on a travelling manifold 711. The wash liquid, the gas, and the granular filter material are all recycled. The cover may be in two parts (713, 705). All operations are controlled by a computer 124.

Description

A PROCESS LIOUID PURIFICATION SYSTEM Description Background In the liquid processing s sectors of industry there is a need for an all encompassing liquid purification system. Traditionally there is a distinction made in liquid processing technology between solid/liquid separation and liquid purification, whereby the former category is equated with the removal of visible suspended matter and the latter with the removal of invisible matter suspended in carrier liquids. Filtration is normally understood as being the physical straining out of particulate matter when passed through a sieve with apertures smaller than the effective major dimension of the particles. However, this definition also fits technologies such as reverse osmosis, ultra-filtration, etc. whereby molecular and ionic dimensions are involved and the term filtration is rarely employed. Macro-particulate separation technologies involving electrostatic forces are seldom applied in the state of the art liquid processing industries.

The traditional liquid purification and filtration technology based on the above mentioned distinctions is presently failing to meet the more stringent demands concerning product purity and environmental protection.

The trend in many of the liquid processing industries is to a rapidly increasing number of products, whereby relatively small quantities of the active components are isolated. The production of these materials is increasingly labour intensive and environmentally unfriendly.

This is in the main due to the manual operation of a large number of various state of the art separation apparatus.

Fig. 10 depicts the evolutionary development of the main separation/purification apparatuses applied in the liquid processing industries. Many of these find ideal "niche" employment in what is a vast variety of different applications. However, with the trend towards multiproduct/multi-purpose methods of production with more stringent product quality and environmental demands, the limitations of these apparatuses are becoming increasingly apparent. A typical production unit of this nature can have between 5-10 different types of apparatus installed. A typical array would be various types of filter presses (Pos.2), pressure leaf and a pressure candle filter (Pos.3), vacuum filters Pos.5/6 and some form of centrifuge (Pos.9). These types of plants are inherently manually operated and generate relatively large quantities of waste-solids and -liquids posing inevitably serious environmental pollution problems. As the automation of such operations is out of the question, the possibility of installing further equipment and manpower for purifying the waste-liquid streams and recycling wash/sterilization fluids is never seriously considered.

Goal of this invention The goal is to devise a single, complete processing system for the liquid processing industries, whereby a universally applicable liquid purification and separation apparatus will play the central role in the production process and fulfill all the requirements of modern fully automated multi-product and multi-purpose production facilities.

In PS GB 2280857 the present applicant describes an innovative pressure filter ofthe moving web type (Pos.8), that fulfills many ofthese requirements and can also be applied advantageously in many product-dedicated producing plants. However the capability of the apparatus and system described in this patent specification still falls short of the requirements of multi-product and multi-purpose operations combined with the elimination of wastewater in fully automatic operation.

Following the teaching of this patent specification, the filter medium takes the form of a belt fabricated from a lenght of a particular quality of web. This is the norm for all other types of belt filters. For multi-product, multi-purpose operation, however, immediate access to a spectrum of qualities, materials and methods is mandatory. The goal is to provide the means and methods to automatically choose and switch to various qualties of media and methods of purification when necessary at any time during the operation.

The operating sequence and apparatus described in GB 2280857 cannot cope with the full array of the required liquid purification techniques especially with regard to ,,deep bed" purification technology. The goal is to provide the genre of apparatus described in the patent with the means and methods of utilizing all known and further innovative methods of liquid purification to achieve a univerally applicable purification system in fully automatic operation.

The fixed nozzle configuration of the suggested plant cleaning apparatus is not adequate for the standard of cleaning resp. sterilization required for the internals of the filter chambers in multi-product and multi-purpose operation, especially in the pharmaceutical, beverage and food sectors, where extremely high standards of cleanliness are required.

With fixed nozzles it is impossible to treat all surfaces with the required impingement intensity.

The media support surface of the lower filtrate chamber in GB 2289057 consists of a pervious plate, which to withstand pressures of up to 10 bar, would be massive and impracticable to remove. In multi-product and multi-purpose operation all internal surfaces must be accessible to jets of cleaning fluids. The design suggested in GB 2289057 does not fulfill this essential requirement. A further goal of this invention is to provide media support apparatus or design that can be manually easily removed to clean all underlying surfaces or whereby all surfaces can be cleaned in situ.

The "hit or miss" nature of state of the art purification technology and that proposed in GB 2280857 when operating fully automatically fail in multi-product and multi-purpose operation. The filtration and purification characteristics of freshly prepared batches of different products, especially of a natural origin, are difficult and mostly impossible to predict or program. If selected media blocks ("fouls") and defies all regeneration attempts, expensive plant shut-downs are inevitable. One of the main goals of this invention is to provide the apparatus and method for pre-testing relatively small samples of liquids to be purified and in programmed operation to select the optimal media and method of purification. The further goal of this invention is to provide the means and method for fully automatically detecting fouling of the media during the production and taking the necessary steps including if necesary choosing and switching to an alternative purification mehtod in order to continue the operation at the targeted rate of production.

The filter chamber and belt equipment in GB 2280857 are enclosed in an enveloping shell fitted laterally with windows. Access to the belt and its ancillary equipment as well as the internals of the filter chamber may be adequate for the processing of a single product by means of a single stretch of medium and a fixed medium support plate, however, with the requirement of multi-medium and accessible medium support elements, all-round accessibility without jeopardizing shell sealing is imperative. A further goal of this invention, therefore, is by means of an innovative design to provide such accessibility combined with security of shell sealing.

According to GB 2280857, the configuration of the hydraulic rams for the actuation of the top chamber is such that the shafts of the rams reduce the available thrust for chamber closure and sealing. This requires the application of much larger dimensioned rams than would be the case if the full internal cross-section were available for supplying the required thrust. Added to this, the rolling or sliding guides attached to the shaft to maintain the movement of the upper chamber in the horizontal position are cumbersome and exposed thus creating a serious safety problem. A further goal of this invention, therefore, is to provide a novel design that enables the utilization of the full cross-section of the rams for closure while retaining the rams in the lateral position as suggested in GB 2280857 and simultaneously providing horizontally orientated actuation of the upper chamber with the essential degree of safety in operation.

With the accomplishment of the above listed goals regarding the further development of the liquid filter described in GB 2280857, the prerequisites for incorporating this innovative liquid purifying aggregate in a complete processing system are realized. The goal is a fully sealed, safe, fully automatic plant for universal application in the liquid processing sectors. To achieve this goal, innovative further development of the recycling techniques of sterilizing/wash liquids as well as gases and vapours will be described.

Description Fig. 1 illustrates a simplified flow-sheet of such a fully automatic plant according to the invention. The filter/purifier and all production vessels can be sealed with respect to the ambient atmosphere during operation, whereby gases and vapours are collected, condensed and compressed at 117, 118 and 116. A granular media regenerator 103 is integrated with the filter housing, whereby the regenerated contents are pumped to the dosing vessels 104. Rolls of disposable filter media are stored externally to the filter housing, whereby in use the self-adjusting band feeding devices 113 are synchronized with the reversing belt drive motor 126. As an alternative, pre-cut individual sheets of disposable media can be installed from storage- cassettes (not shown). The contents offeed/mixing/reactor vessel 107 are either fed under gas pressure or by conventional pumping means directly to a filter/purifier 101 according to an improved version of OB 2280857. The filter residues or beds after filtration or purification are discharged at separate ends of the filter unit. Filtrate is collected in the filtrate receiver 119. Hoppers 105 are installed in a convenient manner to feed powdered or granular purification media such as inert bead-like material, flocculants, zeolites, ion-exchange resins, activated carbon, filter aid, etc. directly or indirectly to the reactor/mixing vessels or to filter dosing tanks 104, 106, the contents of which can also be premixed in a vessel (not shown) with the incoming feed from the mixer/reactor vessels before being introduced to the filter chamber. These purifying substances are also introduced to vessel(s) 108, that is a receiver for used plant wash/sterilizing liquid(s).

A typical operational sequence: A batch of a particular product(s) is prepared in the first reactor/mixing vessel after which in two consequtive separation/purification steps both a solid and a liquid phase are isolated as products, whereby unwanted solutes are also isolated for disposal. The microprocessor 124 is programmed to carry out the operations fully automatically: A set amount of activated carbon powder is dosed from the respective hopper 105 to the contents of the reactor/mixing vessel. According to the programme, a membraneous section of belt 601 with a nominal retention of 0.01 microns is located in the filter chamber after which the chamber is sealed A set quantity of reaction mixture (reactor load cells) is transferred to the filter chamber after which compressed gas from 116 is introduced to the top filter chamber, whereby the effective volumetric flow of gas into the filter chamber as well as the rate of increase of the pressure in the chamber is monitored and controlled by 121,122,123 On reaching a maximum value of pressure, the volumetric flow of gas through the chamber is equivalent to the rate of filtration or flow of filtrate through the filter cake and membraneous section of belt. The end of the filtration is registered by the computer as a rapid drop in pressure and rise in the volumetric flow of gas through the filter cake and membraneous section of belt. The data is processed by the computer 124 and the optimal charge volume for the next cycle to achieve the maximum average rate of filtration is computed and set. Simultaneously the quality of the filtrate is monitored at 125, whereby the command ,,accept" or "reject" is initiated. In the case of "reject", e.g. excessive turbidity or concentration of contaminants, the charge on completion is recycled to the reactor/mixing vessel for reprocessing. On the command "accept" the filtrate charge is transferred to the second reactor/mixing vessel for the second operational step. The residues are discharged at the appropriate end of the filter/purifier and the section of belt is regenerated by high pressure jets of washing fluid. The direction of transport of the belt is reversed by the reversing belt drive motor 126 and the cleaned section of medium is returned to the filter chamber for the next cycle. In a typical operating sequence, on repeating the next few cycles the computer records that the cycle time has increased to a degree that is unacceptable for economic operation. This frequently occuring phenomenon with state of the art filtration apparatus is one of the main causes of costly plant shut-downs. Much non-productive down-time and costly labour-intensive intervention and environmental pollution are usually incurred to return the plant to operation. According to the present invention, in such cases, the computer 124 is programmed to fully automatically feed lengths of,,disposable" membraneous material in roll or pre-cut form 112 to the filter chamber to finish the batch of"intractable" suspension. Such "blinding" material is mostly caused by the uncontrollable precipitation of sometimes minute quantities of unwanted byproducts on mixing or during the reaction. According to the schematized flow-sheet of the invention in Fig. 1, feeding devices 113 deliver specific lengths over an actuated bridging flap 115 onto the moving belt after which slitting devices 114 cut the bands to length. The lengths of medium with the residues are discharged together at one end of the filter at the end of the cycle. As a "last resort" for the case that the consumption of disposable media is excessive or that the minimal required production rate cannot be achieved, the computer is programmed to change to ,,deep bed" filtration technology to be described in more detail concerning the purification of liquid effluent.

In the succeeding production step the batch of purified reaction mixture in the second reactor/mixing vessel is cooled to crystallize the valuable product of the reaction or mixing operation. A minimal sample of the contents of the reactor is introduced to the top filter chamber that seals a section of 1.0 micron membraneous belt material 602. Valve 123 opens, whereby gas under pressure in the top chamber, controlled by flow and pressure instrumentation 121, 122, forces filtrate through a forming cake of solids and the unterlying membraneous section of belt. The filtrate quality (e.g. degree ofturbidity and purity) is monitored by intrumentation 125. An "accept" or "reject" decision is made by the computer 124. On the "accept" signal the cake, washed according to the method described in GB2280857, is "dewatered" and discharged, whereby the membraneous section of belt is regenerated by high pressure jets of fluid such as depicted at 906. The suspension resulting from the belt regeneration operation is normally held and returned to the top chamber for cake washing and product recovery in the following cycle. The regenerated section of belt, now situated in serpentine fashion in a buffer section of the housing 902, is returned to the filter chamber by means ofthe reversing belt drive motor 126 controlled according to the belt movement control described in GB 2280857. Suction ,,dewatering" manifolds 906, 904 connected by means of appropriate stop valves (not shown) to the suction inlet of the compressor 117 remove excess wash resp. regeneration liquid from the belt sections. . The values of the parameters - pressure and time of filtration - of the initial test filtration are used by the computer to fix the optimal feed quantity for the subsequent incremental or batch type operation. In membrane filtration operations, "fouling" or partial blockage of the pores are commonplace due to extremely fine particulate matter becoming lodged in the pores of the membrane. In such cases the impingement of high pressure jets 905 on either side of the membrane is often insufficient to remove them from the pores and the average rate of filtration drops to an unacceptable degree. With state of the art separation equipment, appropriate organic solvents, acids, alkalies, etc. are used to physically dissolve or chemically solubilize and remove such solids. This results in costly plant shut downs, the necessity of reserve apparatus coupled with excessive manual intervention. Such methods are impossible to automate. The present invention enables such techniques to be carried out in fully automatic, computer-controlled operation. The computer 124 registers an unacceptable drop in the rate of production. The partially blocked section of filter belt, instead of being returned to the filter chamber, is transported into a solubilizing bath chamber 901, whereby a reserve section of 1.0 micron membrane in compartment 903 is transported into the filter chamber and sealed after passing through high pressure wash sprays and a dewatering suction manifold at 908, 909.

The operation continues without delay. This procedure can be arranged for multiple grades and types of belt sections. The larger the number of each particular grade and type of section, the longer is the residence time in the solubilizing bath and the more thorough is the regenerating effect. According to the invention, despite the development of severe medium blockage, the separation operation involving a batch of valuable suspended solids in the second reactor/mixing vessel is completed without delay.

Before proceeding with the filtration and purification of a new batch of a different product it is mostly imperative to remove traces of the previous product from all vessels and apparatuses of the operating plant. The contents of 901 are transferred to the soiled storage vessel 108.

Normally, the same liquid as in 901 is used for washing/sterilizing the internals ofthe filter/ purifier 101. Clean washing/sterilizing liquid in 109 is pumped under high pressure through a revolving manifold 125 with the chambers first closed then opened with the filter belt revolving. In the preferred embodiment of this invention for multi-product/multi-purpose liquid processing, the filtrate chamber consists of a plate of corrosion resistive material such as polyvinylidenefluoride (PVDF), polypropylene, etc. machined on the surface to form a filtrate drainage section and belt support 709 and strengthened underneath with encapsulated pressure resisting standard steel profiles as described in GB 2280857. This design is suited for achieving fully automatic clensing and sterilizing operations in the entire interior of the filter chamber. The cleansing devices and methods described in GB 2280857 and the improvement in the form of a revolving manifold 125 can only achieve partial cleaning ofthe chamber internals. Sprays directed into the chamber from an external position cannot reach all the interior surfaces with the required impingement jet velocity. The fixed perforated drainage plate of GB 2280857, with the sealed, inaccessible interior of the filtrate chamber, is unsuited for multi-product operation and the associated cleanliness requirements. According to the present invention when high rates of filtration are required and reduced cleanliness of the filtrate chamber is acceptable, the optimal solution for the design of the filtrate chamber according to this invention is to replace the perforated plate of GB 2280857 with manually removable belt support and filtrate drainage elements 402 consisting of perforated belt support members 403 and and underlying filtrate drainage members 402. Only the smooth floors of the filtrate chamber remain after removal of said elements.

According to this invention, for stringent cleanliness/sterilization requirements with full automation, an innovative apparatus for cleaning and sterilizing the surface-machined plate 712 acting as filtrate chamber is employed A travelling manifold 711 fitted with nozzles 710 is provided with the means in the form of coiled motorized flexible rods 701 situated at the external extremities of the filter chamber with rails 702 to position it centrally in the longitudinal configuration with respect to the interior of the filter chamber to receive a motorized swivelling device 701 and a cleaning feed pinion 704 located externally at both ends of the top chamber sealing cover 705. The pinion is in fluid communication with the clean liquid storage tank 109 through the high pressure pump 110 or other alternative cleaning/sterilizing agents such as live steam. According to this invention, to provide complete accessibility to the machined upper surfaces ofthe filter plate in the filter belt is provided with a special section with apertures large enough to ensure unimpeded access of the jets of cleaning fluie to all surfaces of the drainage profiles machined into the surface of the said plate By oscillating backwards and forwards, the high pressure jets reach and scour all surfaces of both the interior of the top chamber and the filtrate drainage member 709. Similar cleaning facilities are installed in all vessels and apparatus such as 120, 119 which have come in contact with the product(s). In state of the art liquid processing plants, cleaning and sterilizing fluids are discharged either to communal drain or to a centralized effluent treatment plant. In both cases the result is inevitably a serious pollution of the environment. The reason is that conventional effluent treatment plants cannot cope with the ever increasing variety and number of non-biodegradable substances or products used or produced by the liquid processing industries. The further central goal of the present invention is to provide the means and methods for removing these substances from cleaning and sterilizing fluids and other miscellaneous sources within the processing plant, whereby the purified fluids can be economically reused, thereby, if possible, to reduce the effluent from liquid processing plants to zero. With the present world-wide dwindling fresh water resorces, the economic justification for such a goal is self-evident.

According to the present invention, washing and sterilizing fluids from the production operations of each individual product are collected in a vessel(s) 108, to which in batch-wise computerized operation the appropriate purifying agents from hoppers 106 are dosed.

In a typical operation of this type, traces of a wide variety of suspended and dissolved matter are present in the resulting effluent. Each process has ist own specific requirements concerning the acceptability of the purified effluent for recycling. Direct "straining" filtration by state of the art filters illustrated in Fig. 10 is seldom possible. The use of filter aids such as diatomaceous earths, perlites, etc. is mostly prohibitive because of economic, environmental and safety considerations.

According to the invention. the aim is, first, to remove the known undesirable solutes (organic and inorganic) by the dosing of the appropriate extremely finely divided (e.g. mean particle size of 1.0 micron) adsorbent or ion-exchange material from hoppers 105 followed by the flocculation of these and the remaining colloidal material in suspension either narually by pH adjustment to obtain the iso-electric point or by means of flocculants such as polyelectrolytes to produce flocs with a resultant surface charge such that appropriate granular material with a natural or imparted opposite surface charge in a contacting operation effectively attracts and holds this charged flocculated material and also unflocculated but charged material either on its charged surfaces or in its intersticies on bed-formation.

Fig. 11 illustrates schematically the formation of such a bed of spherical beads with positive surface charges attracting and holding negatively charged suspended material supported on a membraneous section of belt 1101.

This innovative technique of liqud purification is utilized to good effect in the main process of the invention. As described above, for the purification of valuable liquids with intractable types of suspended material this innovative ,,deep bed" technique is employed and incorporated into the computer programme for application when the other programmed options are impractical or too costly.

One embodiment of the employment of this technique according to the invention integrates a granular bed regeneration apparatus 103 with the further developed apparatus of GB 2280857 described above. The prepared suspension in 109 is mixed with the said charged granular material from 104 either externally or in the top filter chamber itself, whereby the charged suspended or flocculated material attaches itself to the surfaces of the said charged granular material and forms a bed on a 10 micron sealed membraneous section of filter belt 603.

According to the invention, the optimal operating conditions are established by trial runs with a pilot filter or the production filter 101 itself. A sample ofthe contents of the vessel 108 is mixed with charged granular particles such as glass beads with a diamter of ca 50-500 microns and introduced to the filter chamber sealing the membraneous section of filter belt. After a settling period the beads form a thin bed on the membrane after which compressed gas from 116 is introduced into the chamber forcing the fluid contents through the formed bed of granular material and through the unterlying membrane. A sample of the filtrate is analysed by instruments at 125. In "accept" or ,,reject" (trial and error) programmed tests, possibly involving the dosing of further purifiying substances from the hoppers 105 to the mixing vessel 108 and the dosing tank of the granular material 104, the computer in fully automatic operation establishes the optimal technique for obtaining a satisfactory degree of purity of the filtrate. Using this technique the operational batch sizes are purified with this "deep bed" technology. After washing the bed and forcing the residual liquid from the bed by means of compressed gas from 116, the bed is discharged to the bed regenerator 103. Here by the application of appropriate detergents and agitation (e.g. mechanical or ultra-sonics) the matter adhering to the surface of the granular material is dislodged. Clean liquid is pumped through the perforated support plate in 103 and with a classification action the dislodged material is removed and stored in a back- washing storage tank (not shown) from where periodically the whole batch is purified by the filter 101, whereby a dried residue is discharged for disposal. In larger installations a separate filter/purifier according to the invention is utilized for all effluent purification operations.

I claim the following: 1. A multi-product, multi-purpose liquid purifying process suitable for the recovery of purified liquids from diverse sources (e.g. natural or synthetized), whereby solutes and suspended matter of all types are removed from the carrier liquid as transportable, dewatered residues, thereby characterized, that the process is capable of operating fully automatically without supervision by means of a programmed microprocessor control, whereby all apparatuses are sealed from the ambient atmosphere and all liquid effluents generated in washing and sterilizing such equipment can be purified and reused as part of the automated operations of the sealed plant and that all operations pertaining to solid/liquid separation and liquid purification are carried out by one genre of liquid purifying apparatus, namely a travelling flat bed filter for filtering contaminated liquids from a contaminant supply and delivering filtered liquid to a filtered liquid outlet, the assembly consisting of a section of web of filter medium lying on and supported by a perforated support plate; cover means with dependent rim sections extending downwards, the lower surfaces of which make direct sealing engagement with peripheral portions of the said section of web of filter medium, thus forming an upper contaminant chamber; a receptacle for filtered liquid located beneath the support plate having upstanding rim portions, the upper surfaces of

2. A liquid processing system according to Claim 1, thereby characterized, that all apparatus is contained, whereby gases and vapours are circulated and held in a state of pressure equilibrium by a gas suction/compressing station 116,117,118.

3. A liquid processing system according to Claim 1, thereby characterized, that the plant washing and sterilizing fluids are centrally stored in holding tanks 108,109, whereby batches of soiled fluids in 108 are passes through the liquid purifying apparatus 101 and returned to the purified liquid storage vessel 109 for recirculation to the apparatuses of the system.

4. A plant washing and sterilizing system according to Claims land 3 , thereby characterized, that apparatuses of the liquid purifying process are provided internally with rotating manifolds fitted with nozzles 127 connected to sources of washing/sterilizing fluids.

5. A liquid processing system according to Claim 1 and 3, thereby characterized, that a manifold 711 fitted with nozzles 710 is positioned and provided with the means to traverse the entire cross-section ofthe interior ofthe chamber ofthe purifying apparatus 101, whereby all the exposed surfaces are accessable to jets of washing/sterilizing fluids.

6. A liquid processing system according to Claim 1, thereby characterized, that the receptacle for filtered liquid and the media support surface consist of a horizontal plate, preferably out of plastic, machined, worked or moulded to form a shallow drainage member 709 on the top surface giving complete access to all surfaces in contact with product by washing/sterilizing jets of fluid directed from the interior or exterior of the filter chambers.

7. A liquid processing system according to Claim 1, thereby characterized, that the receptacle for filtered liquid and the media support surface ofthe purifying apparatus 101 consist of a removable elements 402 positioned in a recessed plate 405.

9. A liquid processing system according to Claim 1, thereby characterized, that apparatus 103 and further means are provided to receive directly or indirectly beds of particulate liquid purifying media from the chambers ofthe purifying apparatus 101 and to regenerate said media after which a batch of medium is returned to the filter chambers for reuse.

10. A liquid processing system according to Claim 1, thereby characterized, that the filter web of the purifying apparatus 101 takes the form of an endless belt consisting of a plurality of sections 501, 502, 503 providing different degrees of filtrate quality and/or consisting of different materials.

11. A liquid processing system according to Claim 1 and 10, thereby characterized, that means 504, 505, 506 are provided for individually removing and replacing each section of belt 12. A liquid processing system according to Claim 1, thereby characterized, that the filter web of the purifying apparatus 101 takes the form of an endless belt that is provided with a solubilizing bath 901 external to the filter chambers in which blocked sections ofthe web are regenerated before being reused.

13. A liquid purifying process according to Claim 1, thereby characterized, that a pluratilty of rolls 112 or cassettes of pre-cut disposable filter media of differing qualities are located externally to the filter chambers of the liquid purifying apparatus and are provided with the means for feeding them separately onto the web and into the filter chamber of the said liquid purifying apparatus, where they are supported by the web and after chamber sealing act as a disposable filter medium.

14. A feeding device for rolls of disposable media according to Claim 12, thereby characterized, that the means 113 are provided to cause the contacting surfaces of adjustable feeding rollers to rotate synchronously with the surface of the web feeding device 126, whereby after location in the filter chamber the band is cut to length by slitting devices 114.

15. A liquid processing system according to Claim 1, thereby characterized, that the means for engaging and disengaging the said lower and upper surfaces of the upper cover and lower receptacle of the liquid purifying apparatus consist of laterally positioned hydraulic rams 201, the bodies of which are fixed to a stationary part of the filter framework with the lubricated shafts pointing downwards and connected at the extremities to the lower part of profiled sections 203 free to move vertically and preferably guided by sliding sections 202 out of such material as polytetrafluorethylene attached to the external surface of the hydraulic rams to move and maintain the thrust beams 204, each connected to the top extremities of oppositely positioned profiled sections 203, in the horizontal orientation.

16. A liquid processing system according to Claim 1, thereby characterized, that the purifying apparatus consists essentially of four separate components, namely, a filtrate chamber 712, a filter lid 713, a filter lid cover 705 and a belt containing chamber 713.

17. A liquid processing system according to Claim 1 and 15, thereby characterized, that the filtrate chamber 712 is fixed, whereas the filter lid 713 and the filter lid cover 705 are moveable in the vertical direction both sealing with the upper surface of the filtrate chamber and a belt containing chamber 713 is also moveable in the vertical direction sealing with the lower surface ofthe filtrate chamber 712.