US 3552212 A
Description (OCR text may contain errors)
L. E. UHLIN DEVICE FOR ILEANING THE EXTERIOR OF AN ELONGATED BODY Filed Dec. 3, 1968 INVENTOR LARS ERIK UHLIN ATTORNEY United States Patent Officc 1 3,552,212 i DEVICE FOR CLEANING THE EXTERIOR OF Alf ELONGATED BODY Erik Lars 'Ohlin, Stockholmsvagen 46C,
Stocksund, Sweden I Filed Dec. 3,1968, Ser. No. 780,787
, Claims priority," application Sweden, Dec. 6,1967,
. ..16',779/67 I Int. Cl. G01n 1/14; B08b 3/00 Uls. Ci. 73-423 4 Claims ABSTRACT .OF- THE DISCLOSURE A device for cleaning the outer surface of a take-01f tube in aliqu'id analysis apparatus or other elongated bodies of uniform cross-section. A collar having a bore Slightly larger in diameter than the take-off tube is positioned so that the' portion of the take-01f tube to be cleaned passes through the bore when it is moved up and down to aspirate samples. Suction isapplied to the annular space between'the walls of the bore and the take-01f tube to cause airor a wash-liquid to flow around the-take-olf tube in the bore and entrain any loosely adhering sample -depositson the outer surface of the take-01f tube.
This inventionrelates to a device for cleaning the exterior of an elongated body, and more particularly to a device for removing loosely adhering matter, such as liquid droplets, from the exterior of an elongated member of substantially uniform cross-section, such as a tube or a 3,552,212 Patented Jan. 5, 1971 ferred embodiment of the cleaning device according to the invention.
FIG. 2 is a View similar to FIG. 1 and showing the cleaning device in operation.
FIG. 3 is an enlarged sectional view illustrating the operation of the cleaning device.
Referring now to the drawings and particularly to FIGS. 1 and 2, the liquid-sample analysis apparatus shown therein comprises a housing 11 providing a support surface 12 for first and second elongated sample carriers 13 and 14. Each sample carrier holds a series of sample tubes 15 and 16, only one sample tube being shown for each carrier. As an initial step of the analysis procedure a measured quantity of the liquid sample in each sample tube 15 of the first sample carrier 13 is to be transferred to a corresponding sample tube 16 of the second sample carrier. 14 and mixed therein with a diluent or other conditioning liquid. To this end a transfer device 17 is provided which comprises a take-off probe 18 having a tubular lower portion 19 of uniform cross-section and an bulbuous upper portion 20 connected to a suction source and a supply of conditioning liquid (not shown) through rodQ'Ihe r invention is particularly, although not exclusively,-applicable to apparatus for automatic sequential processing'or analysis of a'series of liquidsamples, and for convenience it'will'b described wtih reference to such application. v Many types of automated apparatus for sequential processingor analysis of aseries of liquid samples supplied in succession from separate containers require that the samples be aspirated from their respective containers as a step of the processing or'analysis procedure. The aspiration of a flexible conduit 21. The take-01f probe 18 is supported by an arm 22 which is rigidly secured to a post 23 on the housing 11. The post 23 is mounted for axial reciprocation and rotation by a mechanism not shown.
In operation of the apparatus the two sample carriers 13 and 14 are advanced step by step and in synchronism with each other along the support surface 12 in a direction perpendicular to the plane of the drawing to sequentially position the sample tubes 15 and 16 in a take-01f position in vertical register with the take-01f probe 18 as shown and a sample receiving position respectively. During each rest period of the sample carriers the post 23 is displaced downwardly from the position shown in FIG. 1 to insert the open lower end of the probe 18 into the sample in the sample tube 15 being in the take-01f position. Suction is applied to the conduit 21 to cause the probe to aspirate a measured quantity of the sample, and the post 23 is then displaced upwardly to withdraw the probe (FIG. 2) from the sample tube 15 and rotated to position the probe in vertical register with the. sample of the tubular probe and aremixed with the next succeeding sample. The inner surface of the tubular probe may be freed for sample residues by passing a wash-liquid through the lumen of the probe, but efficient cleaning of the outer surface often presents a problem, even if the probe is made of a hydrophobic material.
Accordingly, it is a general object of the present invention to provide a device which is capable of effecting an efiicient removal of loosely adhering matter from the exterior of an elongated member. A more particular object of the present invention is to provide a device which is capable of efiecting an efficient removal of sample residues from the outer surface of a tubular probe of a liquidsample take-01f device.
tube 16 being in the receiving position (in the position shown in FIG. 1 the arm 22 is at an angle to the plane of the drawing). In the receiving position the quantity of sample held in the probe 18 is ejected to the sample tube 16 and a measured quantity of conditioning liquid is supplied through the conduit 21 to condition the sample and wash out any sample residues. from the interior of the probe. When the probe 18 is withdrawn from the. sample tube 15, droplets of the sample liquid may remain on the outer surface of the probe portion 19 as indicated in FIGS. 2 and 3, even if the probe is made of a hydrophobic material. If these sample residues are not removed, ,they will be carried over to and contaminate the sample in the next succeeding sample tube 16 when the probe is again moved down to aspirate a new sample so that the analysis result may be false. To eliminate such contamination between samples a cleaning device 24 is provided, and it is with this device the invention is concerned.
The cleaning device 24 comprises a collar 25 secured to the housing 11 between the probe 18 and the sample carrier 13 and having a vertical bore 26 therethrough which is in vertical register with the probe portion 19 source (not shown) is connected to an intermediate enlarged portion 28 of the bore 26 through a conduit 29 and a passage 30 in the collar. The upper end of the bore 26 is in open communication with a recess 31 provided in the upper portion of the collar 25. A suitable wash-liquid 32 may be continuously or intermittently supplied to the recess 31 through a conduit 33 and a passage 34 in the collar.
The operation of the cleaning device 24 is as follows:
When the probe 18 is withdrawn from the sample tube as shown in FIGS. 2 and 3, a film of Wash-liquid is drawn from the recess 31 through the annular space 27 around the probe portion 19 to the suction conduit 29, and simultaneously air is drawn through the lower end of the annular space as indicated by arrows in FIG. 3. Any sample residues adhering to the outer surface of the probe portion 19 are efficiently entrained by the streams of washliquid and air and carried off through the suction conduit 29. If the wash-liquid is supplied continuously, the probe portion 19 is subjected to a similar treatment when the probe 18 is moved down to aspirate a new sample. If desired, the wash-liquid 32 may be supplied only during the upward movement of the probe 18 so that during the downward movement any remaining wash-liquid on the outer surface of the probe portion 19 is removed by air drawn through both ends of the annular space 27.
Depending on the nature of the matter to be removed, the wash-liquid may be dispensed with so that air is drawn through both ends of the annular space 27 during the downward as Well as the upward movement of the probe 18. Generally, however, the supply of wash-liquid is preferred, since it ensures a more efficient cleaning.
The shape of the bore 26 and the relative dimensions of the bore 26 and the probe portion 19 to be cleaned are not very critical, but it will be understood that if the diameter of the bore is too large in relation to the diameter of the probe portion, the flow of wash-liquid and air may be inadequate to ensure an efiicient removal of the sample residues, and if the diameter is too small, the sample residues may be wiped off by the lower peripheral edge of the bore and accumulate on the lower surface of the collar 25. Naturally, the suction applied to the bore has to be adequate to ensure that no wash-liquid drops from the bore 26 into the sample tubes 15 or to the support surface 12.
Although the invention has been described with particular reference to a sample transfer device in a liquid analysis apparatus, it will be understood that it is not limited to such application, which is given only by way of example. It will also be understood that the collar need not necessarily be stationary while the body to be cleaned is displaceable; the reverse is also possible. Thus, the invention may be embodied otherwise than herein specifically illustrated and described, and certain changes in the form and arrangement of parts and in the specific manner of practicing the invention may be made without departing from the underlying inventive idea within the scope of the appended claims.
What is claimed is:
1. A device for cleaning an elongated, vertically mounted member of substantially uniform cross-section, comprising a collar having a bore therethrough and adapted to encircle an axial portion of said member in radially spaced relation to define between the walls of said bore and said member an annular space, means for relatively displacing said collar and said member axially over a length of the latter to be cleaned while retaining said length and collar in radially spaced relation, and suction conduit means connected to said bore between the ends thereof to provide a fluid passageway around said portion of said member through said space to said suction conduit means, said annular space being sufiiciently small so that air drawn therethrough by the reduced pressure from said suction conduit means will entrain any loosely adhering matter on the exterior of said length of said member and being sufliciently large to prevent wiping of such loosely adhering matter from the exterior of said member.
2. A device according to claim 1 and including means for supplying wash-liquid to said space.
3. A device according to claim 1 wherein said collar is provided with a recess communicating with the upper end of said bore and means are provided for supplying wash-liquid to said recess.
4. In combination with an apparatus having a tubular takeoff probe mounted for movement up and down into and out of a liquid-sample container for withdrawing liquid therefrom, a stationary collar having a bore therethrough and adapted to encircle an axial portion of said probe in radially spaced relation to define between the walls of said bore and said portion an annular space, means for displacing said probe through. said bore over a length of said probe to be cleaned, means for supplying wash-liquid to said space, and suction conduit means connected to said bore between the ends thereof to cause said wash-liquid to flow around said probe portion through said space to said conduit means, said annular space being sufliciently small so that the reduced pressure from said suction conduit means will entrain any sample deposits on the exterior surface of said length of said probe.
References Cited UNITED STATES PATENTS 2,009,078 7/1935 ZiSka 134122X 2,565,855 8/1951 Jordan 13464 3,044,098 7/1962 Stalson 15306.1DX 3,266,322 8/ 1966 Negersmith et al. 73-423 (A) 3,430,495 3/1969 Burge 73-423 (A) LOUIS R. PRINCE, Primary Examiner H. C. POST III, Assistant Examiner US. Cl. X.R.