阅读说明：本技术 用于校准滴管的称量器 (Weighing apparatus for calibrating dropper ) 是由 温弗里德·格拉夫 克里斯蒂安·埃洛 于 2014-10-22 设计创作，主要内容包括：本发明涉及用于校准滴管的称量器,其具有称量室(16)、包围称量室(16)的防风部(23)、可拆卸地布置在称量室(16)内的气候模块(34)、布置在称量器里的并提供蒸发率校正值的处理器(32)、布置在称量器上的数据输入单元和可以在气候模块(34)与处理器(32)之间交换数据的数据传输路径。本发明还涉及可松脱地电联接到称量器上的气候模块,气候模块(34)形成封闭的结构单元,并具有空气压力传感器(62)、空气湿度传感器(54)和空气温度传感器(52)以及数据传输路径的一部分,数据能够经由数据传输路径送到气候模块之外的处理器中。本发明最后还涉及借助称量器校准滴管的方法,在校准过程期间确定蒸发率,并依据所确定的蒸发率校正测量。(The invention relates to a scale for calibrating a dropper, comprising a weighing chamber (16), a weather protection (23) surrounding the weighing chamber (16), a climate module (34) which is arranged detachably in the weighing chamber (16), a processor (32) which is arranged in the scale and provides evaporation rate correction values, a data input unit which is arranged on the scale, and a data transmission path via which data can be exchanged between the climate module (34) and the processor (32). The invention also relates to a climate module which is releasably electrically coupled to the weighing scale, the climate module (34) forming a closed structural unit and having an air pressure sensor (62), an air humidity sensor (54) and an air temperature sensor (52) and a part of a data transmission path via which data can be sent to a processor outside the climate module. The invention finally relates to a method for calibrating a dropper by means of a scale, the evaporation rate being determined during a calibration process, and the measurement being corrected as a function of the determined evaporation rate.)

1. A scale designed for calibrating a burette, having a weighing chamber (16), a wind protection (23) surrounding the weighing chamber (16), a climate module (34) which contains an air pressure sensor (62), an air humidity sensor (54) and an air temperature sensor (52) and which is arranged detachably within the weighing chamber (16), a processor (32) which is arranged in the precision scale and is designed to provide evaporation rate correction values therein, a data input unit which is arranged on the scale, and a data transmission path which is configured such that data can be exchanged between the climate module (34) and the processor (32), the climate module (34) forming a closed structural unit.

2. A scale according to claim 1, wherein the processor (32) is arranged to extract the evaporation rate correction value from the evaporation rate correction table or to calculate the evaporation rate correction value.

3. A scale according to claim 1 or claim 2, wherein the climate module (34) is connected to the processor (32) by electrical plug-in or wireless transmission.

4. The scale of claim 1 or claim 2, wherein there is a sensor (58) coupled to the processor (32) configured for determining a degree of ionization within the weighing chamber (16).

5. A scale according to claim 1 or claim 2 wherein there is a light sensor (56) in the weighing chamber (16) coupled to the processor (32).

6. A scale according to claim 1 or claim 2, wherein the processor (32) is configured in such a way that it knows the measurement uncertainty on the basis of the climatic parameters in the weighing chamber (16).

7. A scale according to claim 1 or claim 2 wherein an anti-evaporation trap is disposed within the wind guard.

8. Climate module designed for releasable electrical coupling to a scale according to one of the preceding claims, wherein the climate module (34) forms an enclosed structural unit and has an air pressure sensor (62), an air humidity sensor (54) and an air temperature sensor (52) and a part of a data transmission path which is configured such that data can be transmitted via the data transmission path into a processor outside the climate module.

9. Climate module according to claim 8, characterized in that an electronic memory (60) is provided which can be read from the outside and on which calibration and correction values for the climate module (34) can be stored.

10. Climate module according to claim 8 or claim 9, characterized in that the climate module can also be used as a stand-alone unit outside the scale and via I²The C bus is connected to a USB port of the PC.

11. Method for calibrating a dropper with the aid of a scale according to any of claims 1 to 7, wherein the evaporation rate is determined during a calibration process and the measurement is corrected in dependence on the determined evaporation rate.

12. Method according to claim 11, characterized in that one of the predefined evaporation rates is selected as a function of the climate parameters provided by the climate module.

13. Method according to claim 11, characterized in that the actual evaporation rate is calculated from the climate parameters provided by the climate module.

14. A method according to claim 11, characterized in that the climate parameter is recorded during the entire calibration procedure and that the evaporation rate is modified if a change in the climate parameter has shown that a correction for the calibration procedure needs to be based on another evaporation rate.

Technical Field

The invention relates to a scale for calibrating a dropper and a method for calibrating a dropper.

Background

For gravimetric pipette calibration, high-resolution precision, analytical, semimicroscale, microscale, or ultramicroscale scales are used, all of which are referred to below as scales.

When the nominal volume of the pipette is calibrated gravimetrically by means of a scale, the liquid volume to be determined is discharged from the pipette tip into the weighing container, and the volume of the liquid volume discharged is determined by means of the weighing value. It is known to take into account a plurality of parameters, such as air temperature, liquid density, air humidity and air pressure, since these parameters influence the magnitude of the symmetry. For example, air temperature and air humidity can affect the evaporation rate of the test liquid.

According to the standard, the volume is calibrated to an accuracy of 1 μ l. At the very smallest volumes, the effect of liquid evaporation and hence error on the quantitative results and accuracy of the calibrated pipette cannot be neglected.

In order to keep the evaporation of the test liquid small during weighing, so-called evaporation-proof traps arranged in the weighing chamber are used in pipette calibration applications. The evaporation-proof trap is filled with water, which by evaporation highly saturates the air volume in the weighing chamber with moisture. In this way, a relative air humidity of up to 90% can be achieved.

However, in the case of the use of an evaporation-prevention trap, evaporation of a part of the test liquid during the calibration process cannot be completely prevented. The reason is that the dripping process itself leads to air movement and to an air exchange between the weighing compartment and the surroundings, as a result of which the saturation of the air volume fluctuates.

Furthermore, after a specific liquid volume has been dispensed by the pipette to be calibrated, no valid measurement value can be obtained immediately during weighing, but a certain time has to be waited for. This duration should be less than 60 seconds, taking into account errors due to evaporation. Empirically, this duration is in the size range of 5 to 20 seconds, depending on the resolution, operation and type of scale. It cannot be prevented that already during this process a part of the liquid to be measured evaporates and thus an erroneous measurement result is obtained. This effect is too pronounced at very small volumes.

It is therefore known in the prior art to correct the weighing value by means of a set evaporation rate. Such evaporation rates are determined on the basis of the experiments for the specific container geometry and the relative humidity value in the weighing chamber and are, for example, between 0.05 μ g/s and, for example, 4.6 μ g/s, with an evaporation trap of 0.05 μ g/s when dripping into a flask, which ensures a relative humidity of 90% when the weighing chamber is closed; whereas the drop was 4.6. mu.g/s when transferred into a beaker with the use of an evaporation-proof trap, which resulted in a relative humidity of less than 90% when the weighing chamber was open. These values apply for distilled or deionized water as a instillation liquid according to ISO 3696 with a mass of 3. In calibrating the dropper, a fixed value is typically set for evaporation.

It can easily be seen that the influence of evaporation on the measurement error is not negligible. With the evaporation rate set at 0.26. mu.g/s, an evaporation volume of 3.12. mu.l was obtained in a process time of 12 seconds for the operation and shaking of the scale. The uncertainty of the measurement was 2. mu.l according to the standard EN-ISO 8655-6 in the measurement range from 1. mu.l to 10. mu.l. Therefore, the set evaporation amount is larger than the measurement error. Here, the evaporation rate of 0.26. mu.g/s is again set to a comparatively small value; in the literature, significantly higher values are sometimes mentioned.

In order to reduce the influence of the environment on the measurement accuracy, different measures for quality determination are known in the prior art.

It is known for comparator-type scales to determine the air buoyancy by means of a comparative measurement between two reference objects, the mass and density of which are known beforehand.

It is well known that temperature, air pressure and humidity affect the scale itself. For this reason, in order to compensate for changes in the weighing values which occur when the environmental parameters change, correction factors are stored in the device, for example in the form of curves or tables. For this purpose, temperature and air humidity sensors are arranged in the environment of the weighing cell, for example in a laboratory, and the calibration of the weighing cell itself is then carried out automatically via these sensors as a function of changing environmental conditions.

A weighing device for gravimetrically calibrating a straw is known from EP 1975577 a1, which has a wind protection and an integrated temperature sensor, air pressure sensor and air humidity sensor.

DE 3714540C 2 describes a method for automatically calibrating high-resolution electronic scales, in which environmental influences, such as temperature and humidity changes, detected externally, are taken into account for calibrating the scale itself. The corresponding calibration factor is known from the computer and the weighing result is corrected.

An analytical weighing device with a measured value recorder for environmental parameters is known from DE 29912867U 1, wherein a display is provided on the rear wall of the weighing chamber. The temperature and the air humidity in the weighing compartment and generally the prevailing air pressure are displayed in the display. It is considered here that the surface of the weighing object is humidified in humid air, which depends on the change in the air humidity. The operator therefore knows via the display that, for example, when the air humidity changes, the weighing object should remain in the weighing compartment for a longer time in order to reach a stable final value after humidification. If strong air pressure changes occur, the operator can perform a so-called buoyancy correction by supplying the displayed data to the processor in the scale via the input unit. As regards the temperature, this is used to know the deviation from a reference temperature and to take into account a corresponding correction factor.

Finally, there is a climate-controlled measuring chamber in which the scale is placed. The climate data of the measuring chamber, which are known from the sensors, are input into special software. The software then knows the corresponding correction parameters, which are entered into the scale either manually or automatically.

However, all these measures are not suitable per se for improving the measurement accuracy when calibrating the dropper, since the sensors are preferably placed in the vicinity of the scale, rather than on or in the scale.

Disclosure of Invention

The object of the present invention is to provide a weighing scale which is compact and ensures, with little effort, an increased measuring accuracy when calibrating the dropper.

In order to solve this object, a weighing apparatus is provided according to the invention, which has a weighing chamber, a weather protection surrounding the weighing chamber, a climate module which is arranged detachably in the weighing chamber, a processor which is arranged in the weighing apparatus and provides a correction value for the evaporation rate, for example by reading from an evaporation rate correction table or by calculation, a data input unit which is arranged on the weighing apparatus, and a data transmission path by means of which data can be exchanged between the climate module and the processor. In order to solve this object, a climate module is also provided for releasably electrically coupling to the weighing scale, wherein the climate module forms a closed structural unit and has an air pressure sensor, an air humidity sensor and an air temperature sensor as well as a part of a data transmission path via which data can be transmitted to a processor outside the climate module.

The invention is based on the basic idea of increasing the accuracy of the calibration process in such a way that, on the one hand, a climate value influencing the weighing value of the scale is provided by the climate module. This enables the weighing value to be appropriately corrected directly within the scale. On the other hand, the scale itself is able to know from the climate value the more sensible evaporation rate in the weather shield, which is the basis for correcting the weighing result. The operation with the predefined, set evaporation rate is then not necessary, but rather the operation with the individual, currently determined evaporation rate can be carried out, which is modified starting from the predefined set value, taking into account the actual environmental conditions in the windbreak, or can also be completely re-determined.

The advantage is also obtained that all the components and functions necessary for correcting the weighing values are integrated in the weighing apparatus. No external computer, sensors, etc. are required. Instead, the user can be provided with a compact measurement laboratory, which can even be designed to be transportable. Since the climate module is replaceable (i.e. can be released from the scale without damage), it can be sent to an external research institute or service provider for calibration as required. During this time, the scale may continue to operate by using a replaceable climate module. It is thus possible to calibrate one or (in the case of a plurality of scales) a plurality of climate modules in each case in turn, while measuring with the remaining climate modules.

There is also another advantage in terms of climate modules, namely that older scales can be equipped. For this purpose, only the software of the processor has to be supplemented in addition to the data transmission path.

The scale according to the invention has the advantage, in terms of accuracy, that the climate data in the weather-tight part (and not only in the space in which the scale is located) is measured. Furthermore, since the climate data are automatically transmitted to the processor, transmission errors can be virtually precluded, which are possible, for example, if values from a so-called calibration certificate are transmitted to the calibration software according to DE 29912867U 1.

According to one embodiment, it is provided that the climate module is connected to the processor by an electrical plug-in connection or a wireless connection. In the case of a plug-in part, the plug-in part can be integrated into a mechanical receptacle for mounting the climate module on the weighing apparatus. In this way, a data transmission path to the processor is automatically established when the climate module is arranged in its position in the windbreak. In the case of a wireless connection, the climate module can be arranged at any point in the wind protection, for example on the least disturbed side wall, regardless of whether the plug-in part can be arranged in this location. Furthermore, it is advantageous to dispense with the plug-in connection, so that the interior of the weighing chamber can be made smoother and thus can be implemented more cleanly.

In addition, it can be provided that a sensor for determining the degree of ionization is present in the weighing chamber, which sensor is coupled to the processor. Additional parameters can thus be determined and taken into account when correcting the weighing values. An output signal is generated by a processor in dependence upon the determined degree of ionization. Furthermore, it is possible to indicate to the user via the display that the ionization level in the weighing compartment is too high and that a corresponding countermeasure should be introduced.

It can also be provided that a light sensor is present in the weighing compartment, which light sensor is coupled to the processor. Additional parameters can thus be determined and taken into account when correcting the weighing values. The processor may send out an output signal from a preset incidence of light. The influence of the light incidence on the weighing process can thus be determined in order to take action in the process if necessary. The output signal may also be displayed.

According to one embodiment, it can be provided that the processor is designed in such a way that it knows at least the evaporation rate of the test liquid on the basis of the air humidity and the air temperature in the weighing compartment. In this way, the climatic modules can obtain, in a time-synchronized manner, metrologically traceable climatic values for checking the quality values, which the processor can use to correct the weight values for calibrating the nominal volume of the drip tube by gravimetric analysis.

Preferably, an evaporation-proof trap or a wetting trap is arranged in the windbreak. In this way, the air humidity in the wind guard can be brought as high as possible, so that the evaporation rate is reduced.

According to one embodiment, an electronic memory, in particular an EEPROM, is provided, which can be read from the outside and on which calibration values and correction values for the climate module can be stored. For the calibration, the calibration values and correction values can be stored in an electronic memory, in particular an EEPROM, on the climate module. This is done at an external service provider. When the climate module is subsequently coupled to the scale, this data is directly provided to the processor of the scale for use. Additionally, at least some of the following information for sensor calibration may also be stored on the memory: number of calibration certificate, current calibration value, date of calibration, name of calibration lab and handler, and history of calibration. In the memory of the climate module, so-called uncertainty values can also be stored for each climate variable, so that the calculation of the uncertainty of the evaporation rate can also be carried out by means of a scale, as is the case, for example, for the calculation of the evaporation rate.

Depending on the design, it is provided that the climate module can also be used outside the weighing device as a separate unit and can be used via I²The C bus is connected to a USB port of the PC. This makes external calibration easier. In addition, the climate module may be used in other applications to record air conditioning climate variables without connecting them to a scale. The circuit board of the climate module can have plug-in lugs for this purpose with little effort, so that it can be connected to the USB adapter.

In order to solve the above-mentioned object, a method for calibrating a dropper by means of a scale is also provided according to the invention, wherein an evaporation rate is determined during a calibration process, and the measurement is corrected by means of the determined evaporation rate. In this way, the measurement accuracy or the accuracy of the calibration process is significantly increased, since it is not necessary to base the (less accurately) set predefined evaporation rate on the calibration process, but rather a value that is close to the true, which is relevant to the current climate conditions during calibration.

According to one embodiment, it can be provided that the predefined evaporation rate is selected as a function of the climate parameters provided by the climate module. This evaporation rate may be stored, for example, in a database within the processor of the scale. In this embodiment, the climates are divided to some extent into groups and the evaporation rate is selected in dependence on the respective group (in the simplified example: low air humidity, medium air humidity, high air humidity), by means of which the correction factor for the calibration process is determined. Temperature can also be added here, since temperature also has an influence on the evaporation rate.

According to an alternative embodiment, it can be provided that the actual evaporation rate is calculated as a function of the climate parameters provided by the climate module. In this embodiment, the actual evaporation rate is determined by the processor using the actual climate value.

According to one embodiment, it is provided that the climate values are recorded during the entire calibration process and that the correction factor is modified on the basis of the evaporation rate if a change in the climate values has shown that a correction to the calibration process needs to be based on a further evaporation rate. This embodiment leads to a further improvement in accuracy, since the influence caused by changes in the microclimate in the wind shield during the calibration process is also compensated for.

Drawings

Other features and advantages of the present invention will be apparent from the following specification and drawings referred to below. The figures show that:

figure 1 shows an exploded view of a scale according to the invention,

figure 2 shows a perspective view of a climate module according to the invention that can be used in a weighing apparatus according to the invention,

figure 3 shows a side view of the climate module according to figure 2 without the outer housing,

figure 4 shows a top view of the climate module of figure 2 also without the outer housing,

fig. 5 schematically shows a scale according to the invention, equipped with an anti-evaporation trap, an

Figure 6 shows a flow chart of a burette calibration by a method according to the invention.

Detailed Description

In fig. 1, a high-resolution electronic scale (precision scale) is shown, which can be used for calibrating a dropper.

The scale comprises a weighing cell 14 with a base 12, in which a weighing system, not shown in detail, is accommodated. The weighing cell 14 furthermore comprises a weighing chamber 16, which is formed by a wind shield with adjustable side walls 18, a front wall 20 and a rear wall 22. The weighing chamber 16 is separated from the surroundings by this wind shield. The weighing pan 24 is used for placing a weighing object.

An electronic evaluation system 26, which is embodied here as a separate part, is also electronically coupled to the weighing cell 14 via a cable 28. The display unit 30 coupled to this evaluation system 26 serves not only as a display but also as a data input unit.

Also disposed in the electronic evaluation system 26 is a processor 32 that obtains data from the weighing cells 14. It also contains all the electronics required for the operation of the scale.

In the weighing compartment 16, a climate module 34 is provided, which is designed as a structurally separate unit and which can be mechanically coupled (i.e. can be mounted without any loss of grip) to the rear wall 22 via a releasable plug connection, preferably without the aid of tools.

For this purpose, the rear wall 22 has two slots 36 spaced apart from one another, into which flexible hooks 38 on an outer housing 40 of the climate module (see fig. 2) are latched.

The climate module 34 is shown in detail in fig. 2 to 4.

The outer housing 40 has a number of openings 42 through which the interior of the outer housing 40 enters the weighing compartment 16 and becomes part of the weighing compartment 16, so that the climate inside the weighing compartment 16 corresponds to the climate inside the outer housing 40.

The climate module 34 is electrically coupled via electrical connections with corresponding plug receptacles 44 in the rear wall 22. The plug receptacle 44 is in electrical connection with the processor 32. A plug 46 with a contact 48 on the climate module 34 is inserted into the plug receptacle 44. The plug 46 thus forms part of the module side of the electrical plug-in connection.

As an alternative to the electrical plug-in, wireless transmission, for example WLAN or bluetooth, can be used.

The electrical plug-in (or alternatively the wireless transmission used) forms a data transmission path with which data can be transmitted from the climate module 34 to the processor 32 and, if necessary, vice versa.

The plug 46 is preferably a section of a circuit board 50, on which a plurality of sensors for detecting the climate in the weighing chamber 16 are arranged. Thus, an air temperature sensor 52, an air humidity sensor 54, a light sensor 56 arranged directly in the vicinity of the opening 42 and a sensor 58 for detecting the degree of ionization in the weighing chamber 16 are provided on the circuit board 50, and an electronic memory 60 is also provided. The air pressure sensor 62 is mechanically and electrically coupled with the circuit board 50 via a holder 64.

A plurality of the sensors may also be grouped into a combined sensor.

The wall 66 closes the hood-like outer housing 40, so that an elongated, tongue-shaped section of the circuit board 50, which section is located to the right of the wall 66 in fig. 4, can be inserted into the rear wall 22 and the plug receptacle 44.

Each sensor is coupled to the processor 32 by a respective contact 48. Likewise, the memory 60 is coupled to the processor 32.

The weighing object is then placed on the weighing pan 24, i.e. output from the dropper, so that the weighing object falls onto the weighing pan 24.

Air pressure, air humidity and air temperature are known by the sensors 62, 54 or 52 and the corresponding data is transmitted to the processor 32.

Furthermore, calibration values and correction values for the climate module 34 are stored in the memory 60, which are already stored when the climate module 34 is calibrated.

This calibration is performed outside the scale. For this purpose, the climate module 34 is simply pulled out of the weighing compartment 16 without having to loose the wiring. The climate module 34 is then sent to a corresponding calibration institute, which stores, for example, the number of the calibration certificate, the new calibration value, the calibration date, the name of the calibration laboratory and the processor, and the calibration history on the memory 60. Thereafter, when the climate module 34 is again arranged in the scale, these values are read in full or in part by the application and applied directly to the calculation.

But also the value of the light sensor 56 and of the sensor 58 for determining the degree of ionization in the weighing chamber 16.

For example, when the light incidence increases, a corresponding signal is provided on the display, i.e. for example measuring the consequent change in temperature in the weighing compartment due to the increase in solar radiation is not accurate. Thus, the processor sends out an output signal according to the incidence of the light.

The memory 60 is preferably an EEPROM.

Furthermore, the connection between the climate module 34 and the rest of the scale is via I²And C, bus implementation.

The climate module 34 may be coupled to a computer via a USB adapter plugged into the climate module to calibrate the sensors 52-58 and 62 without having to couple the climate module 34 to the scale 10.

As can be seen, the climate module is designed in such a way that it can also be used outside the weighing scale as a separate unit and can be used via I²The C bus is connected to a USB port of the PC.

An evaporation rate correction table is stored in the processor 32. In a simple embodiment, the table can be stored as a table of values, which are assigned different evaporation rates for different climate conditions. In a more complex embodiment, the evaporation rate correction table can also be implemented as a composite characteristic curve in which the evaporation rates set accordingly are stored as a function of a plurality of climate parameters (for example temperature and humidity). It is also conceivable that the evaporation rate correction table is stored in the form of a mathematical formula, with which the processor calculates the currently set, actual evaporation rate or an evaporation rate correction value from the corresponding current climate data.

Fig. 5 and 6 show in detail how the measuring tube can be calibrated using a scale with a climate module.

In the weighing scale 10 shown in fig. 5, an evaporation-prevention trap 68 is arranged in the wind-guard 23, which is embodied in a cylindrical manner here, and comprises a receiving chamber 70 for evaporating a liquid (for example water). Inside the evaporation-proof trap 68 is arranged a cylinder 72 which rests on the weighing pan 24 and contains the liquid to be dripped.

Figure 6 shows in a flow chart the calibration of the dropper with correction for the effects of evaporation.

When the display unit is embodied as a touch screen and thus serves as a data input unit, the scale can be supplied with the necessary dropper parameters, such as volume or also the calibration liquid used, for example, via the display unit 30, which is not visible in fig. 5, at the beginning of the calibration process.

When the volume of liquid to be weighed is subsequently dripped into the drum 72, the scale recognizes a load change that triggers the measuring process. At the same time, climate data may be recalled from the climate module 34. After pre-checking whether the climate data is in principle reasonable, the processor 32 calculates the set evaporation rate with the help of an evaporation rate correction table. This evaporation rate is used to correct the known weighing value taking into account the evaporation of the dripping liquid.

At the same time, the processor 32 can calculate, taking account of the climate parameters, in which way they influence the weighing values, i.e. for example the measurement uncertainty of the weighing device, independently of the evaporation rate. The measurement uncertainty may be displayed or output by some protocol.

The volume of the dropper to be calibrated can be calculated very precisely with the aid of the weighing values corrected in this way. If the calibration is still insufficient after the current measurement, another pipetting process is required. The process of oscillating the scale and correcting the currently known weighing values is then repeated. The climate that is currently actually present is taken into account again in this correction. If, for example, the humidity in the weighing compartment changes between the first and second measurement, the changed evaporation rate is also taken into account. In this way a very high accuracy of the measurement is obtained. When the process is finished, it is decided whether the dropper is (in this case, the dropper is classified as functioning normally) or not (in this case, the dropper is classified as functioning abnormally and further measures, such as maintenance, are introduced) meets the corresponding requirements.

List of reference numerals

10 weighing machine

12 base

14 weighing cell

16 weighing chamber

18 side wall

20 front wall

22 rear wall

23 wind-proof part

24 weighing pan

26 evaluation system

28 Cable

30 display unit

32 processor

34 climate module

36 gap

38 hook

40 outer case

42 opening

44 plug receiving part

46 plug

48 contact part

50 circuit board

52 air temperature sensor

54 air humidity sensor

56 light sensor

58 sensor

60 memory

62 air pressure sensor

64 holding member

66 wall

68 anti-evaporation trap

70 accommodation chamber

72 cylinder