WO1995019560A1 - Process and device for embedding an object, in particular a sample material, in an embedding mass - Google Patents

Abstract

In a process for embedding a sample in an embedding mass, the sample is arranged in a mould or in a container (7), is at first dried and then embedded in the embedding mass. In the process disclosed, the sample and the container (7) are set into a vessel (17), the sample is dried by heating by means of a microwave heating apparatus (2) located in the heating chamber (4), the embedding mass is introduced into the container (7) inside the vessel (17) and the sample is embedded.

Description

 Method and device for embedding an object, in particular one

Sample material, in an investment

9. The invention relates to a method and an apparatus according to the preamble of claims 1 and 9, respectively.

It is known to embed or pour objects into an investment material in order to e.g. To protect against mechanical damage or environmental influences, to be easier to handle or even to use a visual object when using a transparent investment material, e.g. to create an object of appeal or ornament. This also applies to technical, biological and medical samples in which the embedding in particular for stabilization for optical, e.g. microscopic examinations can serve.

In the case of technical, biological and medical sample materials in particular, it is necessary to dry the sample material before it is embedded in order to stabilize it. The drying process by heating the sample material is associated with a considerable expenditure of time, handling and energy, and two workplaces are also required, namely a heater and a workstation for embedding.

A device required for embedding can be formed by a container or a mold into which the liquid investment material is poured.

In the case of biological and medical sample materials in particular, careful drying is important.

The invention has for its object to develop a method and an apparatus of the types specified above so that the sample material can be embedded with less effort.

This object is solved by the features of claims 1 and 9, respectively.

In the method and the device according to the invention, the heat of vaporization required to dry the sample material is generated by irradiating the sample material with microwaves. This can be done Easy to handle, quick and gentle on the substance, the handling, time and energy expenditure is very low and the sample material can also be heated and dried without damaging the substance. Irradiation with microwaves enables the sample material to be heated directly, particularly in the case of such a sample material that is microwave-absorbing, so that the surroundings of the sample material are not or only slightly heated, which benefits the subsequent embedding process or casting, since cooling at least the Environment of the sample material before embedding is not required. Another advantage of heating by irradiation with microwaves is that a desired evaporation temperature can be maintained more easily, more precisely and more reliably.

The invention also makes it possible to carry out both the drying and the embedding in one and the same container or form, with both the drying and the embedding being carried out in a simple manner in a closed container, so that the sample material is protected from environmental influences, e.g. Air access, is protected or in the presence of a special ambient gas, e.g. can be dried and embedded in inert gas.

It is advantageous to carry out both the drying and the embedding in the heating chamber of the heater, as a result of which no additional handling is required and the drying and embedding can be carried out more safely.

The device according to the invention enables the method according to the invention to be carried out using simple means, the device being characterized by a simple, small and inexpensive construction which ensures a fast, substance-conserving and safe function.

According to claim 19, the invention also relates to a device for the evaporation treatment of solid or liquid substances, or for the preparation or analysis of sample material in a container, wherein this device can also be used advantageously for carrying out other methods for treating substances or sample materials.

The invention and further advantages achieved by it are explained in more detail below with the aid of preferred exemplary embodiments and a drawing. It shows 1 shows an inventive device for drying and embedding sample material in a simplified perspective front view;

Figure 2 shows a holder with a container for receiving the sample material in vertical section.

The main parts of the device 1 are a microwave-effective heating device 2 with a heating chamber 4 which can be closed by a door 3, a holder 5 arranged therein for one or more parking spaces 6 arranged on a partial circle for receiving a sample material or several sample materials, the containers 7 , A suction device 8, a condensation cooler 9, which is arranged in a suction line 11, a gas purging device 12 for gas purging the environment or the container 7, a feed device 13 for an investment material and an electrical or electronic control device 14, which are preferably has a processor and is able to work according to predetermined or enterable programs, the control device 14 preferably being assigned a keyboard and a display or a screen for specifying control data. The controllable individual parts of the device 1 are connected to the control device 14 by control or signal lines.

With the suction device 8, a negative pressure can be generated in or in the vicinity of the container 7, the purpose of which will be described below. In order to prevent the entire boiler room 4 from having to be evacuated to generate the negative pressure and also to protect the boiler room 4 from contamination by investment material, the container or containers 7 are arranged in a housing 16 which consists of a pot-shaped vessel 17 and one Cover 18 exists and to which the suction device 11 and the gas purging device 12 are connected and to which the feed device 3 is also assigned.

The holder 5 is preferably movable in the sense of a carousel in the boiler room 4, in particular rotatably arranged. For this purpose, a rotary drive is provided in the bottom of the heating chamber 4, which is preferably connected in a form-fitting manner by a coupling 21 to the vessel 17 or a base 22 supporting it, which in the present embodiment is pot-shaped with an upwardly projecting peripheral wall 22a surrounding the vessel 17 is. The assigned to the base 22

Coupling part can be formed, for example, by a non-circular recess 23, into which a correspondingly shaped coupling part of the rotary drive 19 with little Borders motion game. The clutch 21 can be released by lifting or pulling out the holder 5 and reinserted by inserting it.

The suction line 11 of the suction device 8 and at least one gas supply line 24 assigned to the gas purging device 12 extend through openings or

Feedthroughs in the housing la of the device 1 into the heating chamber 4 and then further to the inner housing 16. If a holder 5 rotating continuously about its vertical central axis is provided, the feed lines 11, 24 have a rotary coupling which is preferably arranged coaxially to the vertical central axis (not shown for reasons of simplification) ) assign. For a good function, however, it is also sufficient to provide a swiveling swivel drive for the holder 5 and there is no need for a rotary coupling if the supply line sections extending in the heating space 4 are arranged so long and in a loop-shaped manner that the e.g. Swiveling operation that can be pivoted back and forth by approximately 360 ° is ensured.

The vessel 17 has a flat, preferably flat bottom 17a and a preferably hollow cylindrical peripheral wall 17b, on the upper and in particular flat edge surface 25 of which the plate-shaped cover 18 rests and preferably overlaps the peripheral wall 17b with a lower annular shoulder 18a. To seal the cover 18, an annular seal is provided which e.g. is formed by an O-ring 20 arranged in an annular groove of the cover 18 or the peripheral wall 17b.

The suction line 11 is preferably connected laterally to the cover 18 to a channel 26 passing through the cover 18 and opening into the cavity 27 of the vessel 17. By switching on the suction device 8, a negative pressure can thus be generated in the cavity 27 of the vessel 17.

The gas purging device 2 assigned to the suction device 8 is formed by at least one gas supply line 24, which extends from a gas source through the heating chamber 4 and the housing 1 a surrounding it. The gas source, which is preferably arranged outside the housing, can contain a certain gas, for example inert gas. If ambient air is sufficient to purge the cavity 27, the gas supply line 24 can be connected in a simple manner to the surroundings of the device (ambient air). In the present embodiment, the gas supply line 24 preferably penetrates the cover 18 vertically and opens out centrally in an opening 29 on the underside of the cover 18. The gas supply line 28 is preferably connected laterally to a stopper 31, wherein it is continued as an optionally angled channel 32 to the cavity 27. The plug 31 is provided at its lower end with a tapered pin which can be detachably and tightly inserted into a vertical hole 33 in the cover 18 containing the opening 29.

To position the container or containers 7 in the housing 17, a frame 35 is provided, which consists of a horizontal support ring 36 and a frame sleeve 37 projecting upward from its inner edge. The height of the support frame 36 is adapted to the inner height of the vessel 17, so that the frame sleeve 37 abuts the cover 18 with its upper end.

On the support ring 36, the outer diameter of which is dimensioned somewhat smaller than the inner diameter of the vessel 17, there are the positions 6 for the containers 7, the radial transverse dimension of the containers 7 and the radial distance between the peripheral wall 17b and the frame sleeve 37 being so dimensioned that the containers 7 fit between them with play. The containers 7 can each have a lid which can be opened, in particular opened, for filling with an investment material for filling with sample material or, if it seals tightly. In the latter case, the housing 17 is dimensioned so high that there is a correspondingly large free space above the container.

At the upper end of the frame sleeve 37 there is a flange 38 which abuts the underside of the cover 18 and thus closes or seals the cavity 39 of the frame sleeve 37 with respect to the remaining cavity 27 of the vessel 17. The cavity 39 is connected by radial channels or a common underside recess 41 and openings 42 opening upwards in the support ring 36 to the respectively associated container 7, which has an opening (not shown) corresponding to the opening 42 in its base.

The feed device 12 for the investment material has a channel 43 which passes through the cover 18 and which opens into the vessel 17 in the region of the cavity 39. In the present embodiment, the feed device 12 is formed by a funnel-shaped component 44, which rests with its funnel flange 45 on the cover 18 and, with its funnel sleeve 46 forming the channel 33, is optionally firmly inserted into a correspondingly large vertical hole in the cover 18. The plug 31 is inserted with its plug part from above into the funnel sleeve 46. The upper inner edge of the frame sleeve 37 is severely broken by an inner conical surface 37a, as a result of which the frame sleeve 37 is given a funnel-shaped shape.

A second gas purging device 12a is preferably provided, with a gas supply line 24a, which can be a separate gas supply line corresponding to the gas supply line 24 or a branch of the gas supply line 24. The second gas supply line 24a is also formed by a flexible hose, which is preferably laterally connected to a channel 47 which preferably penetrates the cover 18 at an angle, the channel 47 being located outside of the frame sleeve 37 of the suction line 11, preferably opposite it in the vicinity of the peripheral wall 17b Cavity 27 opens.

The gas supply lines 24, 24a or a common gas supply line are assigned, together or in each case alone, a throttle or an adjustable and optionally openable and closable valve 48.

All parts of the device 1 located in the boiler room 4 are made of microwave-permeable material, in particular plastic. This also applies to the base 22, the support frame 35, the container 7, the lid 18, the funnel 44, the plug 31 and the conduit hoses, the vessel 17 being made of a material with slight microwave absorption, in particular glass, and preferably also that Support frame 35 consists of a microwave part absorbing material, which is known per se under the material name WEFLON. A material, preferably a plastic (WEFLON), into which material parts, such as particles of microwave-absorbing material, in particular graphite, are mixed or alloyed, is suitable as the microwave-absorbing material.

The base 22 serves as a drive holder and insulator with respect to the floor of the boiler room. It may be advantageous to arrange an intermediate plate 49 made of microwave-absorbing material, in particular WEFLON plastic, between the base 22 and the vessel 17. It is advantageous to assign two intermediate plates 49 to the device 1, of which one intermediate plate 49 made of microwave-permeable material, in particular plastic, and the other intermediate plate 49 made of microwave-absorbing material. Material, in particular plastic, is so that one of the two intermediate plates 49 can be influenced by indirect installation of an indirect heating of the vessel 17 by microwave radiation. The function of the device 1 is described below. For an embedding process, the same or different sample materials are entered into the containers 7, which are preferably identified by numbers, the vessel 17 and the heating chamber 4 are closed, and the device 1 is switched on, whereby the rotary or swivel drive and a magneton for the microwave radiation are switched on. Depending on the type of material, the sample or samples are heated and dried directly and / or indirectly by heat transfer from the support frame 35, in particular by evaporation. Simultaneously or somewhat later, the suction device 8 is switched on, which not only generates a negative pressure in the cavity 27, but at the same time also generates a gas purge through the supply lines 24, 24a in the cavity 27, through which the resulting vapors are extracted. Due to the negative pressure, the or the evaporation points are reduced, whereby a treatment that is gentle on the substance is achieved with reduced temperatures. The size of the negative pressure can be set by throttling or the valve or valves 48 in the gas supply lines 24, 24a.

The device can be switched off after the drying process has ended, by the operator arbitrarily, according to a specified time or also automatically by means of a switch-off device which detects the end of the drying process and emits a signal for switching off. Such a locking device can e.g. a pressure meter (not shown) which detects or monitors the pressure in the cavity 27 is formed, which emits a signal to switch off when a certain negative pressure is reached. The end of the drying process can be determined by the fact that after the evaporation of the liquid contained in the sample material, there is no further evaporation and therefore the vacuum increases. This increase in negative pressure is then used as a criterion when the drying process is ended.

In order to preserve the sample material in the dewatered state or in the state with removed liquid or in the dried state, the sample material is embedded in a liquid investment material by pouring. The investment material, not shown, is introduced through the feed device 12 into the vessel 17 and into the container 7, preferably from below. In the present exemplary embodiment, the plug 31 or the cover 18 is removed for this purpose. The liquid investment material is either poured into the funnel 44 or directly into the frame sleeve 37 and passes through the channels or recess 41 and the openings 42 into the container 7, in where it rises and embeds the sample material. After the investment material is in the vessel 17, the latter is closed again and the suction device 8 is switched on again, as a result of which a negative pressure is again formed in the vessel cavity. The vacuum ensures that gas bubbles forming in the investment material rise up and are suctioned off. In this way, a bubble-free material is achieved after the preferably transparent investment has hardened. After cooling, the containers 7, which preferably form cassettes, are removed from the rotor. The embedded sample material is particularly suitable for being cut with the associated container 7 or cassette, if necessary, and being examined microscopically.

Before the investment material is poured in, both gas purging streams 51, 52 of the gas supply lines 24, 24a are in operation, the gas purging stream 51 flowing from bottom to top through the containers or the sample material. After the embedding material has been poured in, the flow path of the gas purging stream 51 is blocked, and only the gas purging stream 52 is still in operation in order to maintain the negative pressure and to remove the resulting gases.

Paraffin which is liquid at about 70 ° to 80 ° is preferably suitable as an investment. The liquid paraffin penetrates the liquid or water freed

Sample material and thus acts as a stabilizer, whereby further air access is eliminated.

A control device for the heating power is preferably assigned to the heater. The control device is a temperature sensor T in the area of the holder 5, e.g. an infrared sensor is assigned, which measures the effective temperature in the area of the sample material or a corresponding temperature. A signal corresponding to the measured temperature value is evaluated in the control device in such a way that the heating power is reduced or switched off when the actual temperature exceeds a desired temperature or a desired temperature range, and is increased or switched on when the actual temperature is below the Target temperature or the target temperature range falls.

Claims

Expectations 1. A method for embedding a sample in an investment, in which the sample arranged in a mold or a container (7) is first dried and then in the Embedding compound is embedded, characterized in that the sample and the container (7) are inserted into a vessel (17) and the sample is dried by heating in the heating space (4) of a microwave-effective heater (2) and then the investment compound in the container (7) located in the vessel (17) is inserted and the sample is embedded. 2. The method according to claim 1, characterized in that the sample is embedded in the boiler room (4). 3. Device according to claim 1, characterized in that the sample is dried and / or embedded in the presence of a negative pressure in the vessel (17) or boiler room (4). 4. The method according to any one of the preceding claims, characterized in that the cavity (27) of the vessel (17) during drying and / or embedding is connected to a gas purge stream (51, 52) and suctioned off. 5. The method according to any one of the preceding claims, characterized in that the investment is introduced from below into the vessel (7) and the sample is embedded by the rising investment. 6. The method according to any one of the preceding claims, characterized in that several samples are each used in a container (7) in the vessel (17) and the vessel (17) is moved, in particular rotated, when irradiated with microwaves. 7. The method according to any one of the preceding claims, characterized by the use of an investment which is liquid at a temperature above about 50 °, in particular above about 70 ° to 80 °. 8. The method according to claim 7, characterized by the use of paraffin as an investment. 9. Device for performing the method according to one of the preceding claims, with - A microwave heater (2) with a lockable boiler room (4) - a mold or a container (7) for holding the sample, - a vessel (17), adjustable or arranged in the heating chamber (4), for holding the sample and the container (7) - And one of the container (7) assigned feed device (3) for feeding investment material in the vessel (17). 10. The device according to claim 9, characterized in that the vessel (17) can be closed by a lid (18). 11. The device according to claim 9 or 10, characterized in that the vessel (17) is assigned a suction device (8) whose suction line (11) passes through the vessel (17) or preferably the lid (18). 12. Device according to one of the preceding claims, characterized in that the vessel (17) is assigned a gas purging device (12) for purging the cavity (27) of the vessel (17) with a gas. 13. The apparatus according to claim 12, characterized in that several containers (7) are provided and in the vessel (17) a corresponding number of parking spaces (6) for the containers (7), preferably distributed over a pitch circle, are arranged. 14. Device according to one of the preceding claims, characterized in that the feed device (12) for investment material opens from below into the cavity of the container or containers (7). 15. Device according to one of the preceding claims, characterized in that the vessel (17) is rotatably mounted horizontally and rotatable by a drive (19). 16. Device according to one of the preceding claims, characterized in that a support frame (35) is arranged in the vessel (17) for receiving the container or containers (7). 17. The apparatus according to claim 16, characterized in that the support frame (35) is formed by a bottom part (36) and a shaft (37) extending upwards therefrom. 18. The apparatus according to claim 17, characterized in that the feed device (12) for investment and / or the gas purging device (12) extends in channels of the support frame (35) to the parking spaces (6) and from below into the container or containers ( 7) flows out. 19. Device (1) for evaporation treatment or for preparing or analyzing a sample in a container (17), with a microwave-effective heating device (2) and a holder (5) for at least one container (7) in the heating chamber (4), wherein the container (7) is connected to a feed line (12), characterized in that the feed line (12, 39, 42) extends through the holder (5) and opens into the container (7) from below.