GB2192139A

GB2192139A - Filter for chemical analyzer

Info

Publication number: GB2192139A
Application number: GB08710653A
Authority: GB
Inventors: Daniel Hoerler
Original assignee: Zellweger Uster AG
Current assignee: Zellweger Uster AG
Priority date: 1986-07-02
Filing date: 1987-05-06
Publication date: 1988-01-06
Also published as: GB8710653D0; CH670774A5; DE3715667A1; FR2600908A1; FR2600908B1; IT1206019B; IT8748027A0

Description

1 GB 2 192 139 A 1 SPECIFICATION substances, for example in chlorine

measuring apparatus. Such measuring apparatus requireto be Filter for chemical apparatus and use of thefilterin calibrated from timeto time and forthis purposethe an automatic chemical analyzer watersupplied to the measuring apparatus must be 70 freefrom chlorine. This means thatthe water must This invention relatesto a filter for chemical befiltered during the process of calibration but not apparatus, comprising a filter cartridge which under normal operating conditions.

contains an absorbent material and is designed to be The filter cartridge 1 has a cylindrical form as fitted into a pipe carrying the substance to befiltered. illustrated and consists of a tubularwall 2 closed at In known filters of this kind, the pipe carrying the 75 each end by a lid and a base 3 and 4, respectively.

substance to be filtered is fitted with a three-waytap The lid and base 3 and 4 have each a nipple 5 and 6, upstream of the filter cartridge and a T-shaped piece respectively, for insertion of the filter cartridge 1 into downstream of the filter cartridge and a by-pass the pipe carrying the substance to be monitored, and between these two fittings to by-pass the filter the nipples are also connected together by a tube 7 1cartridge. Apart from the three-way tap being 80 situated in the axis of the filter cartridge 1.

relatively expensive, the insertion of a three-way tap The filter cartridge 1 contains absorbent material and a T-shaped piece is an undesirable complication 8, for example active charcoal, up to a certain which should be avoided if possible. distance from the lid 3 and from the base 4, and the The invention is intended to provide a filterwhich absorbent material 8 is separated from the lid 3 and is simpleto handle in operation and inexpensive. To 85 the base 4 by a suitable filter insert 9 made of a solvethis problem according to the invention, the felt-like material.

filter cartridge has a ductforthe unobstructed The base 4 has a bore extending transverselyto passage of the substance to befiltered by-passing the longitudinal axis of the filter cartridge 1 to the absorbent material and a valve for selectively accommodate a valve slide 10 which has two annular switching the substance to be filtered to the 90 grooves 1 land 12 on its circumferential surface and absorbent material orto the said duct. is displaceable between two positions. When the Since the by-pass and the valve which replacesthe valve slide 10 is in the position illustrated in Figure 1, three-waytap previously used are both integrated the annular groove 12 connects the nipple 6to the with the filter cartridge, the passage for substance to by-passtube 7 so thatthe liquid supplied to thefilter be filtered and handling of the said apparatus are 95 cartridge 1 flows through the cartridge without being simpler and the apparatus is less expensive. filtered. When the valve slide 10 is in its other A preferred additional feature of the filter position after having been pushed to the right, of according to the invention is characterised in thatthe Figure 1, the liquid carried to the filter cartridge 1 filter cartridge is so designed thatthe absorbent flows via the nipple 6 and annular groove 11 through material is replaceable. 100 a bore 13 into a circular groove 14formed in the base Thisfeature hasthe advantage that the filter 4tofacethe lowerfilter insert9, and liquidtherefore cartridge is considerably less expensive than the flowsthrough the absorbent material 8.

disposable cartridges hitherto used which had to be The filter cartridge 1 can therefore be set for discarded once their absorbent material was 'normal operation" or "calibration" simply by exhausted. 105 displacement of the valve slide 10. The nipples 5 and The invention also relates to the use of thefilter 6 and the connecting pieces of the pipe in which the according to the invention in an automatic chemical filter cartridge 1 is inserted are so formed thatthe analyzerfor measuring a substance contained in a connection between the pipe and thefilter cartridge solution. 1 can be established simply by slipping the nipples 5 This use is characterised in that for calibrating the 110 and 6 into position. A suitable holder for the automatic analyzer, the solution is passed through cartridge 1 is provided forthis purpose on the the absorbent material so thatthe substance is apparatus. This holder maybe formed, for example, filtered out and the zero point of the automatic by two elastic clamps into which the wall 2 of the analyzer is set by means of the solution which has filter cartridge 1 can be pushed. The lid 3 and base 4 been freed from the substance. 115 are screwed to the tubularwall 2 and the valve slide Calibration of the automatic analyzer is therefore 10 has three O-rings, one to the left of the annular 1 extremely simple since the apparatus can be groove 11, one to the right of the annular groove 12 switched from "calibration" to "measurement" and and one between these grooves.

conversely simply by moving the valve of the filter

Claims

cartridge. 120 CLAIMS

The invention will now be explained with reference to an exemplary embodiment illustrated in 1. Filter for chemical apparatus comprising p the drawings, in which filter cartridge containing an absorbent material and Figure 1 represents a longitudinal section through designed to befitted into a pipe carrying the a filter cartridge according to the invention and 125 substance to be filtered, wherein the filter cartridge Figure 2 gives a view in the direction of the arrow 11 has a ductforthe unobstructed passage of the of Figure 1. substanceto befiltered, enabling said substanceto The filter cartridge illustrated in the Figures and by-pass the absorbent material, and a valve for marked bythe reference symbol 1 may be used in selectively switching the substanceto befilteredto measuring apparatus for certain chemical 130 the absorbent material orto the said duct.
2 GB 2 192 139 A 2 2. Filter according to claim 1, wherein the filter cartridge is designed for replacement of the absorbent material.
3. Filter according to claim 1 or claim 2, wherein the filter cartridge consists of a tubular wall part and a lid and base closing said wall part, the base containing the inletforthe substance to befiltered andthevalve.
4. Filter according to claim 3, wherein the lid and the base have each a nipple serving as connection to the pipe carrying the substance to be filtered, and in thatthe duct for the unobstructed passage of the substance to be filtered is in the form of a tube connecting the lid to the base.
5. Filter according to claim 3, wherein a filter insert preferably made of afelt-like material is provided between the absorbent material and the lid and between the absorbent material and the base.
6. Filter according to claim 3, wherein the valve is formed by a valve slide displaceable in a bore which is arranged in the base at right angles to the longitudinal axis of the filter cartridge.
7. Filter according to claim 6, wherein the valve slide is cylindrical and has two annular grooves on its circumference and is displaceable between two end positions, each of the end positions bringing one of said annular grooves into communication with the nipple of the base, an annular groove establishing a communication between the said nipple and the absorbent material in one end position while in the other end position the other annular groove establishes a communication between the said nipple and the ductforthe unhindered passage of the substanceto be filtered.
8. Filter according to claim 1 or claim 2, wherein the absorbent material is active charcoal.
9. Filter according to claim 1 or claim 2, wherein the absorbent material is anion absorbent resin.
10. Use of thefilter according to claim 1 in an automaticchemical analyzer for the measurement of a substance contained in a solution, wherein for calibration of the automatic analyzerthe solution is passed through the absorbent material and the substance isthereby removed byfiltration, and in thatthe zero pointof the automatic analyzer is set by means of the solution which has been freed from the substance.
11. Use according to claim 10, wherein the absorbent material used in an automatic analyzerfor measuring dissolved chlorine is active charcoal.
12. Use according to claim 10, wherein the absorbent material used in an automatic analyzerfor measuring dissolved sodium is an ion exchange resin.
13. Afilterfor chemical apparatus substantially as herein described and as illustrated in the accompanying drawings.
14. Use of a filter for chemical apparatus substantially as herein described and as illustrated in the accompanying drawings.

Printed for Her Majesty's Stationery Office by Croydon Printing Company (UK) Ltd, 11187, D8991685. Published by The Patent Office, 25 Southampton Buildings, London, WC2A lAYfrom which copies maybe obtained.