GB2252058A

GB2252058A - Filter cleaning system

Info

Publication number: GB2252058A
Application number: GB9101613A
Authority: GB
Inventors: Fernando Martinez Mugica
Original assignee: Individual
Current assignee: Individual
Priority date: 1991-01-25
Filing date: 1991-01-25
Publication date: 1992-07-29
Anticipated expiration: 2011-01-25
Also published as: JPH0773649B2; JPH0592109A; FR2671983B1; GB9101613D0; DE4105568A1; CH684318A5; FR2671983A1; GB2252058B; DE4105568C2

Abstract

Electro-erosion liquid 24 is filtered as it flows from inlet 11 to outlet 12 of filter 10. Periodically valve 6 is adjusted to reverse the flow through the filter, the backwash liquid flowing via conduit 42 to settling tank 9. Then forward flow is restored to rinse the filter, the liquid still flowing from the filter to tank 9. Finally normal filtration is restored, but the first filtered liquid is recycled through conduit 13' to dirty liquid tank 7 before flow is diverted to normal outlet 13. Tank 9 is divided by adjustable wall 40 with lower apertures 41. During backwashing the flow carries solids through the apertures to settle in chamber 92. Chamber 91 collects relatively clean rinsing liquid which is recycled via valve m, to tank 7. Level sensors O1 to O3 in chamber 91 control the various steps in the cycle. <IMAGE>

Description

2 2 5 E -1 ', -' 1 FILTRATION SYSTEM FOR LIQUIDS WITH SUSPENDED PARTICLES

With the filtration system disclosed in Spanish patent 8900619 it has been found in practice that some of its components can be improved as the following problems have been encountered:

- the liquid included in the settler tank (9) derives from various liquids which arrived at different times with different degrees of dirtiness or contamination, with the result that time and energy is lost in mixing them.

- whenever the system is set in operation after each stoppage a water hammer effect is produced in the filter (10) which stirs up dirt which is not desired in the clean liquid pipe (13).

These problems have been overcome by the applicant in the manner described below.

Figure 1 is a diagrammatical view of the improvements made in the system for the manufacture of liquids with suspended particles.

A non-restrictive embodiment of this invention is described below. This does not in any way rule out other embodiments introducing additional changes which do not differ in their fundamentals; on the contrary, this invention also includes all its variants.

The system disclosed in Spanish patent 8900619 operates as f ollows:

Filtration stage: the dirty liquid (24) pumped by pump (27) follows the following path: primary path (1) - fourth path (4) - upper path (11) of the filter - lower path (12) of the filter - fifth path (5) - second path (2) - pipe (13).

2 Filter washing stage: the filter (10) ceases to perform its function with use and must be regenerated, and for this purpose valve assembly (6) is provided in such a way that liquid is circulated by pump (27) in the following way: first path (1) - fifth path (5) - lower path (12) of filter (10) upper path (11) of filter (10) - fourth path (4) - third path settling tank (9).

Filter rinsing stage: after the filtration stage the filter element (26) is neither in a correct position nor in a correct condition within the filter (10) and there are still particles which have resisted being washed off. In order to overcome this and to be able to begin the filtration stage again the filter is subjected to a rinsing stage in which the liquid circulates as follows: first path (1) - fourth path (4) - upper path (11) of the filter (10) - lower path (12) of the filter (10) - fifth path (5) third path (3) - settling tank (9).

In the improvements it is provided that the settling tank (9) is divided into a first tank (91) and a second tank (92) by means of a wall (40).

Wall (40) may be movable in order to adjust the volumes of the first and second tanks (91), (92) to requirements and a series of holes (11) placed in the first and second tanks (91) F (92) are provided in its lower part.

The dirty liquid from the washing and rinsing stages is returned to the first tank (91) by means of the washingrinsing pipe (42).

The liquid from the washing stage is very dirty and the dirt in suspension tends to sediment out, and as a result of the thrust of the current between the first and the second tanks (91)f (92) through the openings (41) the dirt mainly passes 1-Z 3 into the second tank (92) The rinsing stage is then carried out, producing a cleaner liquid in the washing-rinsing pipe (42) which on entering the first tank (91) carries the small amount of dirt deposited in it into the second tank - (92) in such a way that relatively clean liquid is left in the first tank (91) and dirty liquid and the dirt (44) which has sedimented out, and which can be removed in a conventional way, is left in the second tank ( 92) This results in a tank (91) with relatively clean liquid which can be used in the washing and settling stages, and which can be placed in communication with the dirty liquid tank (7) (relatively dirty) by means of valve (mj.

Level sensors are provided in the first tank (9j, a lower sensor (01), an intermediate sensor (02) and an upper sensor (03) and the provision of similar level sensors in the other tanks falls within the scope of the invention.

When the installation is put into service and pump (27) is operated for the filtration stage a very considerable increase in pressure occurs in the filter (10) causing particles of dirt to be torn away and block pipe (13) which is intended to be only for filtered, i.e. clean liquid.

In order to overcome the problem a fork (131) is placed in filter liquid pipe (13) leading to a dirty liquid tank (7), (9j, in Figure 1 goes to the dirty liquid tank (7).

The system may be manual but it is better to provide it with conventional means of automation in such a way that it can function as follows:

Filtration stage: 1st stage.

4 The dirty liquid (24) is filtered as indicated in the principal patent. Valve (m) in pipe (13) is closed and valve (M2) in fork (131) is opened delivering to the dirty tank (7). This first stage lasts 15 seconds for example.

1 2nd stage. Valve (%) is closed, valve (m) is opened and the system continues to function as described in the principal patent.

Washing and rinsing stages: Valve (m,) is opened and the f irst tank (91) of the settling tank (9) is placed in communication with the dirty liquid tank (7) until the liquid in the first tank (91) reaches the lower level sensor (01). Valve (m,) is closed and the system begins to operate as described for this washing stage in the principal patent, until the level in the f irst tank (01) rises to reach the intermediate sensor (02) whereupon the rinsing stage begins and lasts until the level in the f irst tank (01) reaches the level of the upper sensor (03) 7 whereupon the cycle begins again.

Provision may be made for communication (41) between the first and second tanks (9j, (92) to be regulated.

Claims

1. A system for the filtration of liquids with suspended particles, characterised in that the settling tank is divided into a first and a second tank (91), (92) with communication (41) between them. the washingrinsing pipe (42) leading to the first tank (91) which in turn communicates with the dirty liquid tank (7).

2. A system for filtering liquids with suspended particles according to the foregoing claim, characterised in that communication between the first and second tanks consists of a series of holes (41) in the lower part of the member (40) separating the said tanks.

3. A. system for filtering liquids with suspended particles in accordance with the foregoing claims, characterised in that the outlet from the valve assembly (6) has a fork (131) in the clean liquid pipe (13) which leads to the dirty liquid tank (7).

4. A system for filtering liquids with suspended particles in accordance with the foregoing claims, characterised in that a set of level sensors (01) j (02) 1 (03) is provided in at least the first tank (9,) which together with the signal from the pressure gauge (M) for the pressure in the filter (10) provide the input signals to an assembly automating the system controlling the members (6) (m). (m,), (mJ,, (27) regulating the flow of liquid.

5. A system for filtering liquids with suspended particles as hereinbefore described and with reference to the accompanying drawings