JPH0451777B2 - - Google Patents

Description

Claim 1: Apparatus for qualitative and/or quantitative analysis of liquids, in which the volume of the closed chamber is variable for metering a fixed amount of liquid, and at least two ducts for the intake or discharge of liquids are provided. opening into a chamber, the chamber being formed in part by a cylinder in which a piston is slidably disposed, and in part by a cylinder end member; It passes through the cylinder end member without an opening/closing element and opens at the inner surface of the member, and the end wall surface of the cylinder sealingly abuts against the cylinder end member to close the opening and close the cylinder. and the cylinder end member are movable relative to each other, and this relative displacement unblocks the opening and establishes communication between the corresponding duct and the chamber, and the piston on the discharge stroke A device characterized in that the volume of the chamber is reduced to zero by abutting against a cylinder end member.

2. In the device according to claim 1, several openings corresponding to several ducts are arranged in a circular shape in the cylinder end member, and all of the openings are closed by the surface of the cylinder. Apparatus characterized in that the cylinder end member is adapted to be displaced relative to the axis of the cylinder to expose at least one opening.

3. In the device according to claim 2, the cylinder end member is a circular disk, which is arranged parallel to the control disk, and the control disk is rotatable relative to the circular disk. The rotational ring is prevented from moving in the rotational direction, but is allowed to move in the plane of the circular disk, and the control disk is also engaged with the cam disk and is displaced together with the circular disk. A device characterized in that the plate rotates together with the rotary ring for positioning the control disk, and independently rotates about the cylinder axis with the rotary ring in a stationary state for displacing the circular disk.

4. In the device according to claim 3, the rotary ring and the cam disk have outwardly directed teeth and are adapted to be driven by an individual geared device. Featured device.

5. A device according to any one of claims 2 to 4, characterized in that the cylinder and the cylinder end member are made of ceramic material.

6. In the device according to any one of claims 1 to 5, at least one sensor is provided inside the chamber and is adapted to detect the characteristics of the contents of the chamber. Featured device.

7. The device according to claim 6, wherein the sensor is provided on a cylinder end member.

Description The present invention relates to a device according to the subparagraphs of claim 1. This type of device is used inter alia for volumetric analysis. A common structure is, for example, a piston piuret, as described, for example, in European Patent Publication No. 96088. The piston may be actuated manually or by an auxiliary drive. A precise indication of the volume within the chamber depending on the position of the piston is currently generally provided electronically.

European Patent Publication No. 1137 discloses that the cylinder chamber can be increased in size in a stepwise manner by actuation of a piston or plunger, while various coupling lines can be selectively shorted to the chamber. A biuret-like device is disclosed. Qualitative analysis of the liquid is carried out by draining the cylinder chamber outside into a reaction measurement chamber.

All known piston barrels have a chamber volume that cannot be increased in size starting from zero;
It has the disadvantage that it is impossible to extrude the entire chamber contents from the chamber. this is,
Even when the device has a valve or tap placed directly in the chamber, this always leads to a space being left which cannot be evacuated by the piston. Depending on the purpose of use of the biuret, the residual amount can have a detrimental effect on the respective quantitative and qualitative measurement results. This is a particularly important aspect when the chamber of the brewet itself is used directly as a reaction chamber. In this respect, therefore, the chamber may be filled with various reagents, auxiliary solutions and measuring solutions in a given sequence, or may be emptied in a similar manner, with precisely definable amounts filling the chamber. What is sent within is
It is absolutely necessary, on the other hand, that upon draining the liquid, no residual amount remains in the chamber, which would adversely affect the next measuring operation.

It is therefore an object of the invention to provide a chamber of the type described in the opening part of this specification, in which the chamber can be increased in size starting from zero and can be completely evacuated without any residue left behind. The purpose is to provide equipment. Another object of the invention is to provide a device which can be selectively coupled to the chamber in such a way that when changing from one duct to another, no residual amount of liquid remains in the chamber that cannot be recorded by the measuring device. The objective is to incorporate as many ducts as possible into the chamber in a simple manner from a design point of view. Furthermore, the present invention seeks to make it possible to easily automate the operation of this type of qualitative and/or quantitative analysis.

According to the invention, this object is achieved by a device having the features set out in the characterizing part of claim 1.

Due to the wall part of the chamber itself, which is formed as a cut-off or closure element, a given amount of liquid can be
Starting from a zero chamber volume, it is possible to accommodate the chamber in a surprisingly simple manner and change from the first liquid to the second liquid without uncontrollable residual amounts of the first liquid being left behind in the chamber. Is possible. This principle is based on the fact that the chamber is formed by a cylinder in which a piston is arranged to change its volume, and the shut-off means are located at the end of the cylinder in a wall part displaceable with respect to the cylinder casing. If formed in this way, it can be realized in a particularly advantageous manner. In this way, the closing means may be actuated with the piston in any position. When the piston touches the cylinder end,
The volume of the chamber is equal to zero. When the piston is moved away from the cylinder end, each position of the piston changes the precision of the liquid in the cylinder, especially when the closing means are closed or when a change is made from one duct to another. Accurately correspond to finite quantities. The term piston is used to designate a rotating piston, which is based on the known principle of the Wankel engine and is capable of changing the volume of the chamber by a rotational movement, in certain conditions of use.

Depending on the chosen design shape, the opening of the duct opening into the chamber may be arranged in the displaceable wall part of the cylinder end or in the cylinder casing. However, a particularly simple construction would be advantageous if the displaceable wall part rests sealingly on the end face of the cylinder casing, the entire cylinder end, and the opening can be closed by the end face of the cylinder casing. It will be done. In this way, the surface to be sealed is formed as a flat surface which simplifies the formation of the sealing surface quite considerably. The end surface of the cylinder can easily be formed as an annular surface of sufficient width to fit over the coupling opening.

This construction makes it possible in a particularly simple manner to provide a plurality of openings in the cylinder end, which openings can be connected to the cylinder end and the cylinder casing as required for connecting the individual ducts to the chamber. Related to various ducts without large relative movements between the end faces of the cylinder casing.

The apparatus includes a cylinder end having a circular disk disposed in a flat parallel relationship within the control disk in such a manner that the control disk is rotatable thereabout; The control disk is connected to the rotating ring so as to be non-rotatable with respect to the rotating ring but displaceable in the plane of the circular disk, the control disk being displaceable together with the circular disk by a wedging disk or a cam disk; a rotating ring rotatable about the axis of the cylinder together with the cam disk for the purpose of engaging the control disk to position the control disk and stationary for the purpose of displacing the circular disk; If it can be rotated separately about the axis of the cylinder, it can be mechanically actuated and automated in a particularly advantageous manner. In this way, the cylinder end is movable from a neutral position, in which all openings are closed by the end faces of the cylinder casing, to a predeterminable eccentric position, in which one of the openings opens into the chamber.

The motor drive of the device is provided in a particularly simple manner by means of a rotary ring and a wedge-acting disc, which have an externally toothed configuration so as to be driven individually in rotation by means of a gear drive. A very precise sealing effect at the cylinder end is obtained if the cylinder casing and the cylinder end are made of ceramic material or other suitable materials, such as silicon carbide or sintered material. These materials can be machined to a very high degree of precision and
Quite chemically resistant.

A very high degree of flexibility in the use of the device is achievable if at least one sensor for qualitative analysis of the liquid is arranged inside the chamber. In this respect, it is only necessary to ensure that the placement of the sensor does not create dead space within the chamber.

Embodiments of the invention are described in detail below and illustrated in the drawings. Here, FIG. 1 shows an embodiment with a cylinder end displaceable in a flat manner, and FIG. 2 shows an embodiment with an oblique piston and a cylinder end displaceable about the axis of the cylinder. A reference example is shown; FIG. 3 shows a reference example having a rotary spool at the end of the cylinder that can be displaced laterally with respect to the axis of the cylinder, and FIG. 4 is a sectional view of a preferred embodiment of the device. 5 to 8 are cross-sectional views taken along the plane - of FIG. 4 at various positions of the circular disk, and FIG. 9 is a plan view of the control disk shown in FIG. 4. , FIG. 10 is a schematic illustration of the use of the device according to the invention as a reaction cell, and FIG. 11 is a schematic illustration of the use of the device according to the invention with a separate reaction cell.

1 to 3 show various possible embodiments of the device according to the invention, many variations or even intermediate shapes or combinations being conceivable. The embodiment shown in FIG. 1 corresponds in principle to the operating modes shown in FIGS. 4 to 9. The chamber 1 is defined by a cylinder 3, a displaceable piston 4 and a cylinder end 5. The cylinder end 5 bears sealingly against the end face of the cylinder 3 and is displaceable relative to the cylinder. For example, two ducts 2a, 2b, which can be closed by end faces 7, are arranged at the cylinder end 5. The end face 7 is the cylinder end 5
act directly in combination with a closing means or closing means, and when the closing means is actuated,
It is observed that no residual volume remains in the chamber which cannot be evacuated by the piston 4. Figure 1a shows
The cylinder end 5 is shown in the position where the duct 2b is connected to the chamber 1. In FIG. 1b, the cylinder end 5 is in a neutral intermediate position in which both ducts 2a, 2b are closed by the end face 7. In FIG. The piston 4 abuts the cylinder end 5 in such a way that the chamber volume is equal to zero, without any residual volume remaining behind. In FIG. 1c, the duct 2a communicates with the chamber;
Meanwhile, duct 2b is closed.

In practice, FIG. 1 may for example be used to illustrate a measurement procedure, in which the chamber is cleaned with a cleaning solution via duct 2b. The cleaning solution is then completely removed from the chamber via the duct 2b by pressing the piston 4 downwards, and then the duct 2b is closed as shown in FIG. 1b. Then, starting from a zero chamber volume, a given amount of liquid is sucked into the chamber 1 via the duct 2a, as shown in FIG. 1c. It is recognized that the cylinder end 5 may be provided with a plurality of ducts that can communicate with the chamber 1 in a given or any desired sequence. In this respect, the cylinder end 5 does not necessarily have to be disc-shaped. Furthermore, the cylinder end does not necessarily have to be flat. It is also possible for the cylinder end surface to have a partially spherical shape, in which case the end face 7 and the lower boundary surface of the piston 4 must also have a similar partially spherical shape.

FIG. 2 shows a reference example in which the duct 2 is not provided at the cylinder end but in the cylinder casing or peripheral part 6. This reference example exhibits a function similar to that of the present invention, so its configuration is more complicated than that of the present invention. The volume of the chamber 1 consists of the inner wall of the cylinder casing 6, the interface of the oblique piston 14 and the end plug part 1.
5. The plug portion 15 is non-rotatably connected to the piston rod 16 and thus
It is rotatable about the axis of the cylinder together with the oblique piston 14. When the oblique piston 14 is in full abutment against the plug part 15, the volume of the chamber is equal to zero. Figure 2a shows the location where the duct 2a communicates with the chamber. In this position, the upper part of the plug part 15 covers the duct 2b in an opposite relationship to the duct 2a. FIG. 2b shows the position in which the device consisting of diagonal piston 14 and plug part 15 has been rotated through 180 DEG C. FIG. In this position, the duct 2a
is closed, while duct 2b is connected to chamber 1
It is recognized that it is related to. It is recognized that each duct must be arranged in such a way that the volume of the chamber can be reduced to zero for each duct. This example also recognizes that more than two ducts may be coupled to the chamber.

Finally, FIG. 3 shows a reference example in which the rotating spool 17 is arranged at the cylinder end 5 of the cylinder 3. The spool 17 is rotatable about an axis extending transversely to the axis of the cylinder. Figure 3b shows a partial cross-sectional view through Figure 3a. The rotating spool 17 projects in a given part of the chamber 1 into the chamber 1 and thus forms part of the inner surface defining the chamber. two ducts 2a, 2
b is arranged on the rotating spool 17 in such a way that both are covered by the cylinder end 5 in the neutral position. By rotating the spool 17 in one direction or the other direction, the duct 2a or the duct 2
b can be communicated with chamber 1.
It is recognized that in order to enable the volume of the chamber to be reduced to zero, the piston 4 must have a recess 18 corresponding to the part of the spool 17 that projects into the chamber 1. In this embodiment, the rotating spool 17 may also include a plurality of juxtaposed ducts 2.

FIG. 4 is a detailed view of a preferred embodiment of the invention in which the cylinder end is positioned and displaced by motor drive. The main features of the metering device shown in FIG. 4 are once again the cylinder 3 with an internally displaceable piston 4 and the cylinder end formed as a circular disc 9. Piston 4 is connected to spindle 2
6 by means of a motor (not shown). The relative position of the piston is chamber 1
It can be expressed and observed in a known manner as a given volume of .

In its lower region, the cylinder casing 6 is
It has a somewhat wider wall section, so that the end face 7 of the cylinder casing 6 is somewhat wider than the rest of the cylinder casing. The circular disc 9 is pressed in a fluid-tight manner against the end face 7. Precise machining of the sealing surface allows
The circular disk 9 is attached to the end surface 7 only by a slight adhesive force.
held against. However, the circular disk may additionally be pressed against the end face 7 by a spring force depending on the respective internal pressure expected in the chamber 1.

As can be seen in particular in FIG. 5, in its peripheral area, the circular disc 9 has eight evenly angularly distributed openings 8a to 8h, each opening being a separate tube or It is coupled to the hose 27.

The circular disk 9 is shown as the ninth
It is arranged in a planar parallel relationship within a control disk 10, which is shown separately in the figures. The control disc 10 has a bore 21 into which the circular disc 9 fits in a rotatable manner. The ribs 19 are arranged on the control disc 10 on either side of the bore 21 on a line passing through the bore 21 and the center of the circular disc 9 .

A rotating ring 11 rotatable about the axis 28 of the cylinder is arranged on the control disk 10 .
The rotating ring 11 is directly attached to the cylinder 3 and has an external tooth shape as shown at 13. Rotating ring 11 may be driven by motor 29 via gear 30. The rotary ring 11 is provided on its underside with an entrainment tube 20 having two mutually diametrically opposed grooves 31 .

The rib 19 of the control disk 10 is connected to the entrainment tube 2
0 groove 31. In this way, it can be seen that the control disc 10 is displaceable relative to the rotating ring 11 along an axis defined by the ribs 19, but is non-rotatably connected to the rotating ring 11. Said displaceability of the control disc 10 relative to the rotating ring 11 is an essential condition for the circular disc 9 to be moved from a neutral intermediate position, in which the opening is closed, to an open position, as will be explained further below. .

The control disk 10 is engaged in its outer region by a wedge or cam disk 12 which, like the rotary ring 11, is likewise rotatable about the axis 28 of the cylinder. As shown in FIG. 4, for this purpose the disc 12 is rotatably mounted directly on the lower region of the rotating ring 11. As shown in FIG. Areas of disk 12 that are not rotationally symmetrical in shape are shown in FIGS. 5-8 as hatched areas. Further, the disc 12 may have an external tooth shape as shown at 13, and may be rotationally driven by a separate motor 32 and gears. Because the external toothing of the rotary ring 11 and the disc 12 preferably has the same number of teeth and the same nominal diameter, only a single drive motor can be used to selectively drive the rotary ring 11 and the disc 12. It is recognized that it is also possible to provide this by means of a displaceable gear.

The operating modes of the device will now be explained in detail with particular reference to FIGS. 5-8. In Figure 5,
Cylinder bore 22 is shown in dashed lines. As shown in FIG. 4, the circular disk 9 has all openings 8a to 8h.
is outside the cylinder bore 22 and is therefore arranged in a neutral position closed by the end face 7 of the cylinder casing 6. Then, if the opening 8e is to be connected to the chamber, the disc 12 is rotated in the direction indicated by arrow A, while the rotating ring 11
And the companion tube 20 is stopped. During said rotational movement, the wedge portion 25 starting at the position indicated at 23 and ending at the position indicated at 24 exerts a force on the control disc 10. Since the entrainment tube 20 is stationary, the control disc 10 can only be deflected in the direction indicated by arrow C and is therefore moved together with the circular disc to the position shown in FIG. When this occurs, the opening 8e moves into the area of the cylinder bore 22;
Liquid can thus be drawn in or pumped out through the opening. Disc 12 undergoes a rotational movement through approximately 45° to achieve the open position.

Disc 12 is rotated in the direction shown by arrow B to return the device to a neutral closed position. When this occurs, the wedge portion 25' applies a force to the control disc 10. The rotational movement in the direction indicated by arrow B continues until circular disk 9 is returned to the position shown in FIG.

Then, for example, if the opening 8c is to be connected to the chamber 1, the rotating ring 11 with entrainment tube 20, the disc 12 and the control disc 10
is rotated about the circular disk 9 or about the axis 28 of the cylinder until it occupies the position shown in FIG. When this movement occurs, the circular disk 9
does not change its relative position and remains immobile with respect to the end face 7 of the cylinder casing 6. As soon as the axis of the rib 19 coincides with the desired line of motion of the circular disk 9, the rotating ring or entrainment tube 20 is stopped and fixed. Next, disk 1
2 is actuated again in such a way that the control disc 10 together with the circular disc 9 is displaced in the manner already described above. However, since the relative position of the control disc 10 with respect to the circular disc 9 has been changed over 90°, it is not the opening 8e that is moved into the area of the cylinder bore 22 and thus communicates with the chamber. This is the opening 8c. In a similar manner, opening 8a
Each of 8h through 8h can communicate with the chamber in any sequence. In this way, it is possible to introduce various liquids in precise amounts into or out of the chamber in a very simple and accurate manner.

The practical use of the device in a measuring device will be explained below with reference to FIGS. 10 and 11.

With reference to FIG. 10, the metering cylinder 3 is provided with a piston 4 which is displaceable within the metering cylinder by means of a drive element 29 by a volume-predeterminable proportion or by a volume-dependent proportion depending on the measured value. The drive motor 29, for example a linear motor, is
The counter is operated in a known manner by a control device coupled to the preselection device 33. The control device is
Pulses are supplied to the drive element in a known manner, which pulses cause a movement of the piston rod 16 and thus of the piston 4, the movement being proportional to the number of pulses. By preselection, the number of pulses supplied by the control device 32 and thus the displacement of the drive element 29 can be adjusted by the counter 33. Since the displacement of the piston rod by the drive element is proportional to the change in the volume of the metering cylinder 3, the desired change in volume can be preset in this embodiment of the counter 33. Alternatively, it is also possible to activate the control device 32 and in this way drive element 2
By suitable displacements of the piston rod 9 and the piston rod 16, it is possible to cause a change in volume and to read the change in volume in the counter 33. This method is used, for example, when a titration operation is carried out in the metering cylinder 3. For the purpose of introducing the solution, the cylinder end 5 of the metering cylinder 3 is
There are eight different feed line fittings or openings 8 for lines 35A-35H. The shutoff member is actuated by the valve control device 36 to open or close the opening 8. Valve control device 36
is coupled to the controller 32 by a coupling line 34. Control pulses are supplied to the control device 32 via a coupling line 34, these pulses ensuring that the drive element 29 is actuated only when one opening 8 is opened by the valve control device 36. give.
The feed lines 35A-35F are supplied with reagents and auxiliary solutions from containers 37A-37E, which are shown in schematic form. Feed pipe line 35F, 35G
is coupled to a container 38 of measurement solution. Waste liquid line 35H enters a waste liquid container (not shown).

In order to analyze the measuring solution in the container 38, for example by titration, the device is operated in the following manner. That is, firstly, the opening coupled to the waste liquid pipe line 35H is opened by the valve control device 36. next,
The control device 32 is operated to displace the piston 4 to the left until the piston 4 comes into contact. When this occurs, the solution mixture in the metering cylinder 3 is discharged via line 35H. Next, the opening connected to waste liquid line 35H is closed again. Then, in order to clean the metering cylinder, the opening connected to the line 35A is opened by the valve control device 36, the drive element 29 is actuated by the control device, and the cleaning solution is applied to the piston 4. is sucked into the metering cylinder 3 from the container 37A by a suitable displacement of . The opening of conduit 35A is closed again and the opening of conduit 35H is opened, thus
The cleaning solution can be forced out by displacement of the piston 4 to the left position.

Next, the opening of the conduit 35H is closed again,
The opening of the conduit 35G is opened. The desired quantity by volume may then be preselected in a counter, preselection device 33 and then in a control device 3
2 causes an increase in the volume of the metering cylinder 3 by the desired amount by actuating the drive element 29 and displacing the piston 4. When this occurs, the desired amount of solution is aspirated from container 38. The opening associated with conduit 35G is then closed;
The opening of the conduit 35B is opened. Container 37B
contains auxiliary solutions suitable for the titration operation to be carried out. The control device 32 is then activated continuously or stepwise until a suitable change in the measured value of the sensor is observed in the metering cylinder 3 in a known manner. The control device 32 is then switched off, while the amount of auxiliary solution sucked in via line 35B until this event occurs can be read in the counter 33.

A rotating or vibrating member may be placed on or within the chamber to accelerate mixing of the liquid within the chamber. In this respect, stationary volumes should be excluded in a similar manner as for sensors. It is thus possible, for example, for the piston itself to be rotated and/or pulsated.

Containers 37C-E provide additional auxiliary solutions in performing the multi-step process. For example, during the course of the operating procedure, the cleaning solution may be drawn into the metering cylinder 3 from the container 37A via the line 35F and then sprayed into the container 38 so that the container 38 is cleaned.
Container 38 is then evacuated again via line 35G, after which the wash solution is directed via line 35H to a waste container (not shown) by suitable valving.

As shown schematically, two ion-sensitive electrodes 39 are placed at the cylinder end 5 as sensors. Electrodes 39 are provided for measuring the ion content in a manner known per se. The electrode is flush with the inner wall of the cylinder end so that no dead space is formed when emptying the metering chamber 3. Electrode 39 is coupled to an evaluation circuit (not shown). Measuring cylinder 3 in a very simple manner
It is recognized that it is possible to carry out extremely precise ion content analysis operations. Precisely predeterminable amounts of measuring solution and reagent or auxiliary solution are drawn into the metering cylinder 3 in sequence without additional metering devices, such as e.g.
directly analyzed within.

It will be appreciated that the ion sensitive electrode 39 may be replaced by any other sensor depending on what type of reaction or analysis operation is to be carried out within the metering cylinder 3.

FIG. 11 shows a modified embodiment in which the movement of the piston rod 16 and the operation of the shut-off member occur in the same manner as in the embodiment shown in FIG. The valve control device 36, the control device 32 and the preselection device 33 as well as the drive element 29 are therefore not shown for clarity of the drawing. The embodiment shown in FIG. 11 has only two containers 37A, 37B for reagents and auxiliary solutions, in which the solution to be analyzed is located. Unlike the embodiment shown in FIG. 10, the embodiment of FIG.
It additionally has a reaction or measuring cell 40 which is connected to the metering cylinder 3 via D, 35E. For the purpose of metering the solution to be measured and the auxiliary solution, the desired mixture is obtained by suitably sequential actuation of the shut-off member and a simultaneous increase in the volume of the metering cylinder 3 by displacement of the piston 4. It is inhaled in a manner similar to the embodiment shown in the figures.
However, the contents of the metering cylinder 3 are then discharged via the line 35C into the reaction measuring cell 40 after the appropriate opening has been opened and then detected by the sensor 39 and the evaluation device 41. Analyzed within cell 40.

It will be appreciated that the apparatus shown in FIG. 10 may be combined with an apparatus such as that shown in FIG. Thus, for example, various sensors may be arranged at the cylinder end 5 for a given analytical operation. The solution may then be analyzed directly in the metering cylinder 3 by these sensors in the manner described above. Additional reaction measuring cells 40 may be connected to the metering cylinder 3 if further analysis operations are to be carried out, for which the installed electrodes 39 are not compatible.