JPH0422224B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a volumetric dilution device that can be used in hospital chemical analysis equipment, in particular in flame photometers.

This type of automatic equipment is old in the art. Some of these include two pistons for reagent and sample volumes and one or more valves, using common type syringes and specialized equipment.

Devices with more than one valve are in fact very expensive and prone to many failures.

Prior art devices with only one valve tend to admit air, which allows the dilution ratio to be varied and
Furthermore, these devices are influenced by the viscosity of the sample.

Therefore, in these cases, the operator usually operates the diluter by hand with the aid of a micro cylinder.
The two chambers must be filled carefully so that air bubbles are completely eliminated. This cannot be achieved in any other way.

The volumetric dilution device according to the invention is therefore completely revolutionary in its particular industrial field.

In particular, it is novel in that it is self-priming and has the advantage of automatically expelling entrained air bubbles upon start-up.

Secondly, it is novel in that for all practical purposes it is not influenced by the viscosity of the fluid being analyzed.

The above points are achieved through certain design features of the diluter, the most important of which consists of a transparent and therefore easy-to-inspect acrylic container, which contains the diluent volume and sample. It incorporates two chambers for each piston, each serving a volume, said chambers having dimensions such that the pistons do not contact the walls of their respective chambers during their stroke, except for the seals.

A second feature of the invention is that the gap between the piston and the respective wall is such that it allows air bubbles to escape to the top.

A third feature of the invention is that the chamber of the piston, which determines the volume of the sample to be analyzed, has a hemispherical dome section at the top.

A fourth feature of the invention is that the two reagent liquid inlet and outlet tubes are concentrated at the midpoint of the dome.

A fifth feature of the invention is that the two tubes have equal cross-sections and the joint of the tubes has a cross-section that is substantially the same as the cross-section of each tube.

A sixth feature of the invention is that the sealing rings of the two pistons are fitted into the lower parts of the two chambers containing the pistons.

A seventh feature of the invention is that the two pistons have maximum freedom of movement in the horizontal plane and virtually zero freedom in the vertical plane. These features and other features of lesser importance will become more apparent from the following description in conjunction with the accompanying drawings, which illustrate preferred embodiments of the invention.

As can be seen in the drawings, the volumetric diluter according to the invention (see figures 1 and 2) makes it self-priming, allowing automatic evacuation of entrained air bubbles on start-up and whose operation is consistent with all practical requirements. It has design features that make it insensitive to the viscosity of the fluid sample being analyzed for this purpose.

With reference to FIGS. 3 and 4, the device has an upper transparent part 40, preferably made of acrylic resin and of fundamental importance from the point of view of the invention, and a covering by a metal sheet 54, which is adapted to cover the device. It consists essentially of a lower support portion 44, which is necessary for operation but is not critical from the point of view of the invention.

The two parts 40, 44 are threaded in the lower part and have a bolt 8 which engages in a special suitable recess.
8 and 30.

Lower part or support part 44 of the device (see Figure 3)
contains a cam assembly 42 having a C-shaped cross section and sliding up and down along the shafts 36,38. Said lower part is provided with a recess designed to seat the bottom parts 17, 19 of the pistons 16, 18.

The piston rods 16', 18', together with the cam assembly 42 with which they are integral, slide within bushings or sleeves 32, 34 whose lower ends engage seal rings 70', 66'.

The most important part from the operational point of view of the pistons 16, 18, namely the head, is also located in the special chamber 12, 1.
4, these chambers are designed to accommodate the diluent and sample sucked in or expelled by said piston.

As can be clearly seen in FIGS. 3 and 4, the chamber 12 is located at the head of the piston 16, except for the seal 70.
In such a way that it does not come into contact with the walls of the chamber during the reciprocating process.
It has dimensions. The same is true for chamber 14 with respect to piston 18, which only contacts seal 66 during its reciprocating stroke.

The chambers 12, 14 are adjoined at their bottom by sections 13, 15 (FIG. 3) of different cross-section, which sections form the seats for the bushings 32, 34.

A recess 11' is provided at the top of one side of the transparent part 40, which recess is designed to accommodate a block 11 into which the typical upper or dome-shaped part of the chamber 14 is incorporated, and whose midpoint to 2
Two reagent inlet tubes 22 and one outlet tube 22' are concentrated.

The cross-sections of the tubes 22, 22' are the same and the cross-sections at their junction are also the same.

As is clear from a comparison between the cross-section of the chamber 12 and the cross-section of the head of the piston 16 and between the cross-section of the chamber 14 and the cross-section of the head of the piston 18,
A gap is created between each wall so that air bubbles can be easily released towards the top.

As previously mentioned, the seals 70, 66 are connected to the chambers 12,
13 and into the intermediate portions of chambers 14, 15 (see FIG. 4), the intermediate portions having substantially the same dimensions as the seals.

The outline of the operation of the diluter according to the present invention is as follows.
It is clearly shown in the figure.

During the first suction phase, the diluent contained in the container 26 is pumped into the chamber as the piston 16 is lowered.
2 and at the same time the sample to be diluted is drawn into chamber 14 by needle 10 from a suitable container containing the sample when piston 18 is lowered.

Substantially the diluent contacts the outlet point 26' of the container 26 and the inlet tube 20 within the chamber 12, and the sample to be diluted passes through the tube 22 to the domed top 1 of the chamber 14.
4'.

The downward stroke of the pistons 16, 18, as well as the upward stroke of the pistons which occurs in a second phase, called dilution, occur simultaneously to actuate the solenoid valve 24. During said suction phase, the solenoid valve 24 connects points 24' and 24'' via its terminals, i.e. connects the container 26 and the diluent chamber 12. During the second dilution phase, the piston 1
6 and 18 are the chambers 12 and 1 due to the movement of the eccentric body 50.
It is raised again to 4th grade. At the same time, solenoid valve 24 separates container 26 and connects points 24'' and 24 via its terminals, thereby causing chamber 1
2 and 14 are connected. The diluent thus flows from chamber 12 through inlet tube 22' into chamber 14;
Here it mixes with the sample contained therein and then, by means of the completely different cross-sections of the two rods of the pistons 16, 18, the diluted sample is discharged from the chamber 14 through the outlet tube 22 and through the needle 10. introduced into the container.

3 and 4 show a front view of the support 44 of the device with a cam assembly 42, which in its top has recesses 41, 43 for the bottoms 17, 19 of the pistons 16, 18. ,moreover,
It has another recess in its center with curved shorter sides 46 in which a shaft 48 rotates.

The shaft 48 is integrated with a cam 60 and its shafts 62, 62' through an eccentric body 50 (see FIG. 5), and the cam 60 is fastened to the shafts 62, 62' by screws 58.

With the aid of a microcomputer or similar means (not shown), the solenoid valve 24
The optical position encoder and the eccentric body 50 can be controlled by a gear motor 64 integrated with the cam 60.

Also shown in FIG. 5 are the mounting screws 52, 52' of the sheet metal cover 54 of the cam assembly 42. The foregoing is merely a description of one preferred embodiment of the container diluter according to the invention, and many modifications may be made by those skilled in the art without departing from the true spirit and scope of the invention as defined in the claims. It can be imagined.

[Brief explanation of drawings]

FIG. 1 is a schematic representation of the device in the suction phase. FIG. 2 is a schematic representation of the apparatus in the dilution stage. FIG. 3 is an exploded view showing a partial cross section of the device. FIG. 4 is an assembled view showing a partial cross section of the device. FIG. 5 is a sectional view taken along the line -- in FIG. 4. Figure 6 is the 4th
It is a sectional view taken along the line - in the figure. FIG. 7 is a sectional view taken along the line -- in FIG. 5. 10... Needle, 12, 14... Chamber, 16,
18... Piston, 20, 22... Inlet pipe, 24
... Solenoid valve, 26 ... Diluent container, 3
2, 34... Bushing, 36, 38... Shaft, 40... Transparent part, 42... Cam assembly, 44... Supporting part, 48... Shaft, 50
... Eccentric body, 60 ... Cam, 62, 62' ... Shaft, 64 ... Gear motor, 66, 70 ... Seal, 68 ... Optical position encoder.

Claims (1)

Claims: 1. Under a microcomputer or similar means, during the lowering of the pistons 16, 18 in the suction phase, the chamber 12 for the diluent volume is automatically connected with the container 26 containing the diluent; , during the lowering of the piston 18 for the sample volume, it is possible to separate said chamber 12 from the chamber 14 containing the sample to be analyzed, which is sucked in by the needle from another special container; Also, during the dilution phase, when the pistons 16, 18 are raised, they automatically separate the chamber 12 containing the diluent from the container 26 containing the diluent, and also separate said chamber 12 from the container 26 containing the sample to be diluted. can be connected to a chamber 14 so that the sample is thoroughly mixed with the diluent and discharged together with the diluent by means of the needle 10 into another suitable container;
It incorporates a solenoid valve 24 controllable by a gear motor with an eccentric 50 and a piston 16 for the diluent volume and a piston 18 for the sample volume to be analyzed, the bottom of which is connected to said pistons 16, 18. suitable drive means 4
A base 44 with a C-shaped cross section serves as a support for
an acrylic resin transparent container 40 joined to the acrylic resin transparent container 40, the transparency of which allows constant inspection of the container and the presence or absence of reagents therein; The rods of the pistons 16, 18 which move up and down have dimensions considerably larger than those of the rods, so that the walls of said pistons 16, 18 are connected to their lower seals 70, 18.
With the exception of 66, the chamber 12 for the diluent volume is provided so as not to touch the walls of said chambers 12, 14.
and a chamber 14 for the sample volume, and a wall of said chamber 12, 14 serving as a dilution volume and a sample volume, in order to allow automatic evacuation of air bubbles or other gaseous media formed in said chamber 12, 14. and a piston 1 moving within said chambers 12, 14.
6 and 18, a dome-shaped top portion 14' provided in the sample volume chamber 14, and a joint provided on the top of the dome-shaped top portion 14', respectively. 2 having substantially the same cross section
A volumetric dilution device comprising: two tubes 22, 22'. 2. The position of the solenoid valve 24 is changed by changing the position of the cam 60, driven by the gear motor 64, with respect to the optical position encoder 68, which together with the cam 60 forms an assembly 42 supported by the support portion 44. The eccentric body 50 which is changed and is integral with said cam 60 at the same time changes the position of the pistons 16, 18 which are also integral with said assembly, and the assembly 42 connects the two shafts 3 with the upper transparent part 40 and the lower support part 44.
6, 38 in both directions. 3. The cam assembly 42 connects the pistons 16,1
upper recess 4 engaging with enlarged bottom portions 17, 19 of 8;
1,50, thereby pistons 16,18
is integral with the cam assembly 42 and the movement of the piston in both directions is determined by the rotation of a shaft 48 in a recess 46 provided in the center of the cam assembly 42, said shaft 48 being 2. The volumetric dilution device according to claim 1, wherein the volumetric dilution device is integrated with the cam 60. 4. Volumetric dilution device according to any one of claims 1 to 3, characterized in that it makes it possible to use sample and reagent in a preferably 1:100 ratio. 5 Seal ring 7 of two pistons 16, 18
0.0,66 is fitted into the lower part of the two chambers accommodating the pistons, the cross-section of said lower part being substantially the same as the cross-section of said sealing ring. Volume dilution device according to any one of. 6. The rods of the two pistons 16, 18 always have maximum freedom of movement in the horizontal plane and essentially zero freedom of movement in the vertical plane. The volumetric diluter according to any one of items 1 to 4.