System for evenly applying liquid to a surface

(54) Title: Procedure and apparatus for applying liquid to a surface (56) Published publications: GB 1 415 182, GB 1 476 096

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The present invention relates to a method and apparatus for applying liquid to a substantially flat surface of an object, and the invention is particularly intended for applying liquid to one surface of a slide, the invention being intended to quickly and evenly color a plurality of slides arranged one after the other.

For microscopic examination of certain materials, especially cellular materials such as blood, tissues and the like, a small amount of a liquid or a substrate containing the material (e.g. a small amount of plasma containing blood cells) or a thin section of the material itself is usually placed (e.g. thin slice of animal or vegetable tissue) on a transparent plate or slide. The material is then stained by contacting it with solutions that color only certain constituents of the material or cells, providing a contrast that facilitates the investigation.

Different staining methods were used to give different results. For example, one can use a solution that stains a translucent substrate and thereby provides contrast to substantially colorless cells. Other solutions can be used to achieve color differences between different parts of the cells. Solutions can use; for staining only certain parts of a cell, for example the cell nucleus but not the cytoplasm. In a method called negative staining, colorless cells are not obtained against a colored background. Some methods are relatively simple and require only the use of a fatal solution. However, other methods are complicated and require the use of a relatively large number of solutions in succession.

In many staining methods, some solutions are used only to prepare the substrate or fix it, while the actual staining is effected by one or more natural or synthetic dyes. The dyes, of course, will be after them ;; suitability for the current type of cells and the desired staining. Examples of the types of dyes commonly used are oxazine, triphenylmethane and thiazine.

In a known staining method, the slide is usually dipped in succession in a series of containers with different solutions, the slide being retained in each solution for a predetermined time, in some cases several minutes, before moving to the next solution. Usually, the last container contains a detergent, for example water, and after dipping into it, the slide is dried prior to examination. These operations can be done manually or i. an automatic equipment developed for this purpose.

Depending on the properties of the material to be dyed and the type of dyeing desired, as many as twelve solutions are required in this process. Of course, the fact that you often have many slides increases the problems. Furthermore, when the slides are passed one after the other through the same container with a solution, for example if you dip the slides, there is also a risk of contamination of the solution. This risk increases if the same solution is used in different staining procedures for different types of materials and substrates.

In another method, slides are colored by dropping a dye on the surface of the slide. Then, a buffer blank is added and an air jet is used to mix the buffer blank and the dye on the surface of the glass. Of course, it is of great importance that the air jet is carefully controlled in order to obtain an even distribution and mixture of buffer substance and dye.

US Patent J '01,886 discloses a device for automatically applying a single liquid or a plurality of liquids to the lower surface of a substantially horizontally arranged slide, which is moved at some distance and substantially parallel to a flat liquid application surface. This device is now generally used for applying one or more liquids to a slide.

In some cases, however, even better control of the liquid application is desirable, so that even greater accuracy with regard to the staining intensity and uniformity can be obtained. It is also desirable to increase the processing speed of an automatic equipment.

The object of the present invention is to provide a method and apparatus for treating a surface of a substantially flat object with a liquid to enable automatic application of liquid dye to materials supported on a plurality of sequentially arranged slides. In addition, the invention is intended to enable automatic coloring of materials on a slide by bringing the material in contact with a number of solutions in such a way that fast and uniform coloring of the material is obtained and a regulation of the coloring intensity as well as the possibility of distinguishing different components of the material. , wherein the device according to the invention is intended to provide increased capacity and comprises an improved control device for controlling the function of the device. According to the invention, a number of consecutively arranged objects with flat surfaces, for example slides, are fed along a predetermined path over a flat liquid application surface, whereby treatment liquid is injected into the space between an object and the flat liquid application surface where the object moves into position or position. position over the liquid application surface, whereby the object's performance is temporarily interrupted when the object is in position over the liquid application surface. When the object is in this position, liquid is applied to the object. When a predetermined time elapsed after the application of liquid (for example, 10 sec, to 1 minute), the movement of the object along the predetermined path was again initiated. The interruption described in the movement of the objects and the feeding of the objects from station to station give a uniform application of the liquid to. the surface, which is described in more detail below, and allows for increased capacity of the device in comparison with the method heretofore used; to apply liquid to flat objects as they are moved continuously over a flat liquid dispensing surface.

The invention is described in more detail below with reference to the accompanying drawings, in which Fig. 1 is a perspective view of a device according to an embodiment of the invention, which device comprises a feeding device; Fig. 2 is a plan view of part of another feeding device; Figure 3 is a side view of the device of Figure 2, viewed along line 5-3; '4 is a schematic view of a slide with a staining pattern that could occur upon processing in a device; Fig. 5 is a schematic view of a slide of substantially uniform staining obtained with the device of the invention, and Fig. 6 is a circuit diagram of the control circuits of the device of the present invention.

Very generally, the present invention relates to a device for automatically applying a single liquid solution or several liquid solutions to at least one surface of a substantially flat article. The device is particularly useful for automatic dyeing of materials on one surface. of each of a plurality of successively arranged slides. The one in fi_;\. 1, a staining device 10 includes a plurality of liquid application statons 13, 14 and 15 and feeding means including helical conveying means 17 and 18 for feeding substantially flat objects, for example translucent glass sheets 20, 2] and 22 past the liquid delivery stations. A liquid application device at each of these stations automatically contacts one surface of each glass sheet with a specified amount of the desired liquid.

In order to provide a high capacity compact apparatus, the feeding device is adapted for discs, for example the disc 21 which are arranged substantially parallel to the surfaces facing each other, each disc being arranged so that it is on a long side and therefore

7711293-6 is in a substantially vertical plane. When the discs are advanced by the feeding device, they are folded forward (the disc 21) so that they are finally flat and are arranged with their edges substantially parallel in a horizontal plane (see the disc 22) as they pass through the liquid application stations. When the disks have passed stations 1J and 14, they are washed at station 15 and then automatically ejected from the feed cleaning.

As can be seen from the drawings, the device 10 comprises a pair of gables 27 and 28, a front wall 29 and a rear wall 50. For ease of description, the device 10 is shown without a lid, so that one can see the different parts of the device.

The feeding device comprises a substantially horizontal groove extending in the longitudinal direction of the device and comprising a pair of substantially parallel rails 25, only one of which is shown in Fig. 1 and which are arranged adjacent and substantially parallel to each of the helical conveying means 17 and 18. The rails 25 are spaced less than the length of a standard sized slide. Typically, such a slide has a length of about 75 mm and a width of about 25 mm. The rails 25 may be separate bars or may be formed as a common, U or I-shaped member. In a device of this kind, each of the slides on the rails 25, which cooperate with the slides at some distance from the ends thereof, stands.

In the feeding device shown in Fig. 1, the slides are advanced along the rails 25 in such a way that their mutual distance is maintained at a predetermined value. In this embodiment, the conveying means 17 and 18 are substantially helical and located on the outside of the rails 25, the conveying means being driven by a drive motor, for example the motor shown in Fig. 6. The motor rotates the transport means 17 and 18 in opposite directions and therefore moves the objects, for example the slides along a predetermined path. Conveniently, the conveying means are substantially equal except for the direction of pitch of their helical portions. The pitch of the helical portions of the conveying means 17 and 18 may vary along the length of the members. As shown in Fig. 1, the pitch of the helical portions at the right part of the conveying means is relatively small. The distance between adjacent turns in each helical portion is in this range only slightly greater than the thickness of the article to be treated, for example a slide. At the central portions of the conveying means, the pitch of the helical portions increases so that the distance between

7711293-6 adjacent turns increase to a value slightly greater than the width of the items being processed. These gradient changes allow the slides to be folded from eight substantially vertical positions (perpendicular to the plane of the web) to a substantially horizontal position (parallel, but the plane of the web). Since the helical portions of the conveying means 17 and 18 are intended for interaction with slides, they are conveniently made from a material with high resistance to abrasion against glass, for example, pre-chromed stainless steel or aluminum with a coating of hard material, for example NITUF or the like. Hard coatings are prepared using a high current density and low temperature electrolytes to provide coatings of greater thickness and density than conventional anode coatings. These hard coatings can be, for example, Alumillte, Martin, Sanford or Hårdes.

The outer and inner diameters of the conveyors 17 and 18 are such that: the smallest distance between the means; less than the length of a standard type slide. For example, the disk or slide 22 is fed along the rails 25 between adjacent turns of the helical portions of the conveyors 17 and 13. . The conveying means can be driven by the separate driver rotor using an unshown gear which causes simultaneous rotation of the conveying means in opposite directions. This means that the conveyor 17 rotates clockwise while the conveyor 18 rotates counterclockwise, as seen in Fig. 1. Because the helical portions have different pitch directions, the slides are fed from right to left through the device.

The. It should be noted that the interchange device may include gears or chains. It should also be noted that, if desired, two conveying means having the same pitching direction are used if the driving means are such that both conveying means rotate in the same direction.

The slides are moved to the left past the various liquid delivery stations due to the rotation of the conveying means 17 and 18. The slides com processed in the illustrated device are coated with the material to be stained on the underside of the slides as they are moved horizontally past the liquid delivery stations. Two separate liquid dispensing stations 13 and 14 and a washing station 15 are shown on the drawing nerve. However, it should be noted that the number of stations can be changed and that the device shown relates only to a particular staining method for staining blood material. In carrying out the Wright method in the device, the dyeing liquid is applied to the first station, followed by a buffer liquid mixed with appropriate means, e.g.

A mixing loop (not shown) is applied at the second station and a washing liquid is applied at the third station. The fluids are supplied from containers 33-36 by suitable pumping means, for example peristaltic pumps 37-40, and discharged through apertures 42-44 in bottom plates 46. Suitable means, e.g., easily actuated switches^J18-5O, which are actuated by threads in the slide movement, can be used to control the pumping means.

Each liquid application station, for example the station 13, comprises a flat upper liquid application surface on a solid support plate 46 which is firmly mounted in the space between the rails 25. The support plate is positioned so that its liquid application surfaces at the stations 13, 14 and 15 are adjacent to and adjacent. the plane containing the upper surface of the rails 25 so that the liquid application surfaces are parallel to and adjacent to the lower surface of a slide 22 supported by the rails 25. The substrate plate is provided at each liquid application station with an aperture 42, 43 or 44 through which a predetermined amount of liquid can be introduced into the space between the liquid application surface of the substrate plate 46 and a slide located above it to insert the lower surface of the slide and the material thereon. with the liquid. Since the bottom surface of the slide is the liquid surface application surface, for example, at a distance of a few tenths of millimeters (for example 0.1-0.3 mm), the surface tension of the injected liquid is sufficient to provide complete filling of the space between the two flat surfaces, and therefore the lower surface of the slide passing the liquid application surface on the support plate 46 to be contacted with the liquid screen.

As shown in Fig. 1, the support plate 46 is conveniently formed as a unit with transverse recesses or grooves 52 defining the liquid application stations 13, 14 and 15.

If desired, other recesses or grooves may be provided in the support plate. The purpose of these grooves may be to convey liquid over the slide and / or to remove excess liquid. The number, size and position of these grooves may vary depending on the particular staining method used.

It has been found that if a slide, for example slide 22, is advanced over the substrate plate 46 in a continuous motion, a circulating motion is produced in the liquid film between the underside of the slide and the liquid application surface of the substrate plate. This circulation, the movement is effected by the fact that the liquid is introduced into objects—

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Ί the glass one side through an opening, for example the opening 42, while the slide moves over the support plate 46. Continuous movement of the slide along the path causes the treatment liquid to be puffed in a particular pattern due to the surface tension and the other properties of the liquid in conjunction with the movement of the slide across the surface of the slide. An image of a pattern that may occur under these conditions is shown in FIG. 4, which shows that in the case of a liquid application of this kind an uneven liquid application is obtained. This cannot be allowed in some cases, especially if the slides are to be analyzed automatically.

Attempts have been made to reduce these irregularities and allow uniform application of liquid to the slide. In addition, attempts have been made to increase the speed of the slides by automatic staining devices. In this way, it has been found that intermittent movement of the slides and application of the liquid when the slides are not moving gives a very uniform application of the liquid without the irregularities obtained in previously known methods. In this way, it is possible to allow faster feeding of the slides between the liquid delivery stations, so that the capacity of the device is increased. The shelf life of the slides at the liquid dispensing stations may vary between 10 sec and 1 min, with 30 sec being common in staining according to Wright's method. Fig. 5 shows schematically the uniform staining obtained by using the present invention.

Another device for feeding slides along the rails 25 is shown in Figs. 2 and 5. In this arrangement, the conveying means of Fig. 1 have been replaced with the upper portions of endless chains 55 and 56 extending opposite sides of the support plate 4ύ and the rails 25. The slide, 2 is moved along the rails 25 of the projections 57 and 58, the chains 55 and 56, which projections extend slightly beyond the upper surface of the rails to cooperate with the slide 22. It should also be noted that other devices for pre-wetting the slides can be used.

Fig. 6 shows the electrical wiring diagram of the device, and from this it can be seen that a single phase AC motor 60 with three connections! seals and a capacitor are used to drive the device which feeds objects or slides over the flat liquid application surfaces. The motor also operates chambers 76 and 77 which are connected to switches 68 and 77 respectively. 72nd The motor 60 has a direct connection to a strictly connected connection 60a as well as separate windings (not shown.) For driving clockwise or nine turns, whereby one end of each 11 mining is connected to the connection 60a. The other end of each winding is connected within a terminal 60b and 60b, respectively. 60c, and one not shown

A capacitor is provided between terminals 60b and 0c in motor 6ύ. Wires 65 and 66 connect the terminals 60a and 2, respectively. 60b with an alternating current source 62 with a ground wire 6j5. The switches 68 and 72 are held in the open position by associated cams as shown in Fig. 6. Starting the motor 60 causes rotation of the chambers 76 and 7'7, so that the associated switches 68 and 7 respectively. 72 closes. When switch 68 is closed, a timing means 70 is coupled into a adjustable timing switch 75 with a normally open switch 71, which then closes. The switches 71 and 72 are connected in series in a line 78, one end of which is connected to the motor connection 60c and the other end of which is connected to line 65, which means that when both switches 71 and 72 are closed, both windings in motor 60 are coupled to current source 62, which provides dynamic braking of motor 60, so that this stops. The dynamic braking is therefore accomplished by shunting the capacitor with both motor windings engaged.

By appropriately adjusting the chambers 76 and 77, the motor stop position can be synchronized with the arrival of the slide to a liquid application station, and the slide remains in this position while liquid is applied until the actuator 70 opens the switch 71 and deactivates the dynamic braking of the engine 60, thereby activating the starter 60, chambers 76 and 77 for continued feeding of the slides. This process is repeated as the slide reaches the next liquid application station and the chambers 76 and 77 again allow closure of switches: nos 68 and 72.

From the above it can be seen that the invention fulfills the objects set forth at the outset and provides valuable advantages. The above-described device makes it possible to feed substantially flat objects in a new way from a consecutive feeding station past one or more processing stations in a predetermined position, the objects being treated with liquid. In the illustrated embodiment of the invention, a large number of slides can be automatically and sequentially treated with staining liquids in a manner that provides uniform staining over the surface of the slide and permits a capacity which is increased by 35% -100 $ when compared to prior art staining devices of the kind. as disclosed in U.S. Patent No. 5,888. Instead of moving continuously along the support plate, the slides are fed intermittently but relatively quickly between the liquid delivery stations and liquid is applied while the slides are essentially stationary at the liquid delivery stations.

771293-6 dye as well as the formation of secondary staining patterns which sometimes occur during constant feeding of the slide relative to the substrate plate. In contrast to prior art devices where the slides are moved at a constant rate when dye and buffer liquid are applied, the present invention allows better control of color intensity and separation of different cell parts. The color intensity is largely a function of the time during which the sample on the slide contacts the dye, and this time can easily be set independently of the advance rate of the slides between the liquid dispensing stations by adjusting the time switch 75 to increase or decrease the time the slides are stationary at the liquid station. . Intermittent movement of the slides with relatively fast movement between the liquid delivery stations provides increased capacity of the device for automatic staining of slides.

The invention provides all the advantages that can be achieved with a device for automatically staining slides. For example, it eliminates the cumbersome and monotonous work that was previously required to prepare microscope slides. The invention also provides economical advantages in staining because only a small amount, usually about .1 of liquid, is required for staining an object gias at each station. In addition, new dye was used for each dyeing operation. Furthermore, improved quality and reproducibility are obtained as a result of eliminating the human factor, which provides uniform function at each step.

The invention is, of course, not limited to the above-described exemplary embodiments, but changes can be made within the scope of the following claims.

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