JPH0442619B2 - - Google Patents

Description

Claim 1: The diluent is set inside the container by the weight of the diluent in order to dilute the sample with the final weight of the diluted sample determined by the weight of the sample in the container before dilution and the set dilution factor. an apparatus for diluting a sample up to a dilution factor f, which comprises: (a) an apparatus for repeatedly measuring the weight W of the sample and diluent inside the container; and (b) a selection for setting the dilution factor f. (c) a device for calculating TW, where TW is the weight of the sample in the container before adding diluent to the dilution factor f;
(d) a device for calculating the value (TW-W); and (e) a reservoir of diluent for the purpose of diluting the sample in the container to a selected dilution factor f. (f) a liquid guiding device disposed between the reservoir and the container to allow diluent to flow from the reservoir to the container; (f) when TW>W, to direct the flow of diluent between the reservoir and the container; connected to the device for calculating the value (TW-W) to allow and to block the flow of diluent between the reservoir and the container when TW=W;
A device comprising: a valve device for controlling the flow of diluent between the reservoir and the container.

2 In order to dilute the sample with the final weight determined by the variable sample weight in the container before dilution and the set dilution factor, the device dilutes the sample in the container up to the dilution factor f using the weight of the diluent. , (a) a device for repeatedly measuring the weight W of the sample and diluent inside the container; (b) a selection device for setting the dilution factor f; and (c) a device for calculating TW, where TW is the weight of the sample in the container before adding diluent to the dilution factor f
(d) a device for calculating the value (TW-W); and (e) a reservoir of diluent for the purpose of diluting the sample in the container to a selected dilution factor f. (f) a liquid guiding device disposed between the reservoir and the container to allow diluent to flow from the reservoir to the container; (f) when TW>W, to direct the flow of diluent between the reservoir and the container; connected to the device for calculating the value (TW-W) to allow and to block the flow of diluent between the reservoir and the container when TW=W;
A device comprising: a pump device for controlling the flow of diluent between the reservoir and the container.

*Specification [Technical Field] The present invention relates to an apparatus for carrying out the dilution of a sample of any weight with a diluent up to a predetermined weight ratio of the diluent.

In the fields of microbiology, biochemistry and chemistry, it is often necessary to dilute liquid or solid samples to some predetermined weight concentration using diluents. For solid samples, a liquid diluent is used to create a slurry of solid in liquid. Bacterial density in solid food or fruit juices is determined by analysis of dilutions of these samples. In some areas, such as clinical or quality control laboratories, it is necessary to perform multiple sample dilutions. Although it is possible to manually dilute the sample to a predetermined weight or volume ratio using a diluent, the amount of time required can be significant if high precision or large amounts of dilution are required. obtain.

[Disclosure of the invention]

The present invention relates to a device for diluting a liquid or solid to a predetermined concentration by weight of diluent.

The present invention uses a diluent set inside the container to perform sample dilution with the final weight of the diluted sample determined by the weight of the sample in the container before dilution and the set dilution factor. In an apparatus for diluting a sample to a given dilution factor f,
(a) a device for repeatedly measuring the weight W of the sample and diluent inside the container; (b) a selection device for setting the dilution factor f; and (c) a device for calculating TW.
TW is the weight of the sample in the container before adding diluent divided by the dilution factor f, and (d) the value (TW
- a device for calculating W); (f) When TW>W, the liquid guiding device allows the diluent to flow between the reservoir and the container, and when TW=W, the diluent flows between the reservoir and the container. characterized in that it comprises a valve device for controlling the flow of diluent between the reservoir and the container, connected to said device for calculating the value (TW-W), in order to cut off the flow of diluent between the reservoir and the container. Provide equipment.

Furthermore, the present invention dilutes the sample according to the variable sample weight in the container before dilution and the final weight determined by the set dilution factor. (a) a device for repeatedly measuring the weight W of the sample and diluent inside the container;
(b) a selection device for setting a dilution factor f; and (c) a device for calculating TW, where TW is the weight of the sample in the container before addition of diluent divided by the dilution factor f; and (d) a device for calculating the value (TW-W); and (e) a device located between the diluent reservoir and the container for the purpose of diluting the sample in the container to a selected dilution factor f. , a liquid guide device that allows diluent to flow from the reservoir to the container; (f) when TW>W, allows the diluent to flow between the reservoir and the container;
And when TW=W, in order to cut off the flow of diluent between the reservoir and the container, the flow of diluent between the reservoir and the container is connected to the device that calculates the value (TW-W). A pump device for controlling the pump device is provided.

In the present invention, the valve device has (TW-W)<
1, it is possible to prevent an excessive amount of diluent from being added to the sample for any value of f. The present invention also provides an apparatus for defining a maximum weight limit UL that is satisfactory for some dilution factor f for the total weight of sample and diluent, and a minimum weight limit UL that is satisfactory for some dilution factor f for the total weight of sample and diluent. and a device for defining a weight limit value LL.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing one embodiment of the present invention, and FIG.
1 is a flowchart illustrating a preferred embodiment of microprocessor control for the embodiment of FIG.
and FIG. 3 are configuration diagrams showing another embodiment of the present invention.

[Best mode for carrying out the invention]

FIG. 1 shows an overall view of an apparatus 10 according to the invention which serves to automatically dilute a sample 11 held in a container 20 to a dilution factor f by a predetermined weight of diluent 36. According to the invention, dilution of the sample 11 is performed without the need to weigh the sample before filling it into the container 20.
The dilution performed according to the invention is due to the weight proportion of the diluent in sample 11. The dilution factor f of the present invention is defined by the following formula. That is, f = weight of sample / weight of diluent + weight of sample For example, for ethanol diluted with 100 g of water
The 100 g solution is diluted to a weight dilution factor f=0.5, which is equivalent to a weight dilution of 50%. In accordance with the present invention, there is provided a weighing machine 12 having a container weight controller 14, which has an output line that continuously produces a signal of the weight placed on the pan 18 in Binary Coded Decimal (BCD) format. It has 16. According to the invention, this container weight control device 14 is placed on the line 16 when the pan 18 has a container 20 resting thereon, in which the sample 11 to be diluted by the diluent 36 will be placed. weight is zero
Energized to generate a BCD output signal. The weighing machine is a commercially available weighing machine that has a container weight correction function, and is a BCD weighing machine that can be used in the present invention.
The output device is manufactured in Hightstown, New Jersey, USA.
Manufactured by Mettler Instrument Corp.
It is PS15.

The controller 22 of the present invention includes a dilution factor selector controller 24, an automatic feeder switch 26, and a first rapid control system for the flow of diluent 36 from reservoir 38 through line 40 under the action of pump 42. A quick acting supply switch 32 used to manually open the acting supply valve 34 and a pump 42.
a slow-acting switch 4 used to manually open a second valve 46 to the flow of diluent 36 from reservoir 38 through line 40 under the action of
4, a ready indicator light 46A, an expensive sample indicator light 48, an indicator light 50 indicating lack of sample, a power source 52 for the indicator light, and a maximum weight control device 53.
and a minimum weight control device 55. The aforementioned maximum load controller 53 defines the maximum weight of sample and diluent allowed for dilution of the sample up to a certain dilution factor f. The minimum weight controller 55 controls a certain specified dilution factor f
Specifies the minimum weight of sample and diluent allowed for dilution of sample to A manual fast-acting supply switch 32 and a manual slow-acting supply switch 44 are connected to supply valves 34 and 46 by controller 22 to enable selective flow control of diluent into container 20. Can be used to manually override automatic controls. The first supply valve 34 has a rated flow rate for a pressure that is ten times greater than the flow rate of the second valve 46 . The control device 22 has an interlocking line 54 attached to the chassis of the weighing machine 12 and connected to a switch 54A, so that the horizontal member 7 is connected so that the switch 54A is closed when the stanchion 74 is rotated.
6 , valves 34 and 46 are on vessel 20 , and power line 56 provides appropriate power to weighing machine 12 .
Then, the container 20 is supplied from the storage section 38 via the conduit 40 and either the first supply valve 34 or the second valve 46.
and a pump energization line 58 that controls the operation of pump 42 to pump diluent 36 within the pump 42 in the manner described below. The power line to the control device 22 has been omitted. The conduit 40 connects the pump 42 and the first
and a T-shaped section having an input side connected to the and second supply valves 34 and 46. A valve control line 64 is connected between controller 22 and first supply valve 34 to selectively control the flow of diluent 36 from pump 42 through the first valve in a manner described below with respect to FIG. It is connected. Valve control line 66
is connected between controller 22 and second valve 46 for selectively controlling the flow of diluent 36 from pump 42 through second valve 46 in the manner described below with respect to FIG. . Supply valve 34 and valve 46
has a solenoid that is energized under the control of an energization signal from controller 22 via control lines 64 and 66. Supply valve 34 and valve 46 are manufactured by Skinner Precision, New Britain, Conn.
A V5 type valve commercially available from Industries, Inc. will suffice.
A bacterial filter 68 connects the first and second supply valves 3 to filter the diluent 36 before discharging into the container 20.
4. Can be connected between the outlets 70 and 72 of the valve 46. Supply valve 34 and valve 46 are supported on container 20 by metal stanchions 74 and horizontal members 76.

FIG. 2 is a flowchart illustrating a preferred implementation of a controller 22 of the present invention that uses a microprocessor to control the operation of the device. Starting point 2 of this microprocessor control program
Let us assume that at 00 the following sequence of events occurs. That is, the maximum and minimum weight values UL and LL of the sample and diluent are entered, the dilution factor f is set, the power is turned on, the sample container 20 is placed on the pan 18, and the container weight controller 14 is turned on. The sample 11 is placed in the container 20, and the automatic feeder switch 26 is turned on. The program proceeds to block 202 where the ready indicator light on the controller is shut off to indicate the loading of the sample into the dilution. The program proceeds to block 204 where the weight W of the sample to 0.1 g in BCD form is read from the weigher 12.
The program continues to block 206 where the weight W is stored in memory. The program then advances to block 208 where the dilution factor f is determined by the dilution factor selector controller 24 within the controller 22.
read from. Next, the program starts with block 2.
Proceed to step 10, where the dilution factor f is stored in memory. The program continues to block 212 where the sample and diluent maximum weight limit UL is read from the maximum weight controller 53 in the controller 22. This maximum load limit range is 0<UL<
It is 9999g. The program proceeds to block 214 where the maximum weight value UL is stored in memory. The program then proceeds to block 216 where the sample and diluent minimum weight limit LL is read from the minimum weight controller 55 of the controller 22.
The range of this minimum weight limit value is 0<LL<9999g. The program proceeds to block 218 where the minimum weight value LL is stored in memory. next,
The program proceeds to block 220 where the calculated weight value (TW=W/f) is calculated and rounded to the nearest 0.1 g. The program then advances to block 222 where the value TW is stored in memory. The program then reaches decision point 224
Then, it is determined whether the value TW>UL. If the answer is "yes", the program branches to block 226 where the excess weight indicator light 48 in the controller 22 is illuminated to add the sample and diluent to achieve the previously set dilution factor f. indicates that the weight is greater than the specified maximum weight set by the maximum weight control device 53.
The program then proceeds to block 228 where memory components are set by switch 28 in controller 22 to prepare the device for another dilution. The program then advances to a stopping point 230, where all operations in the program end. If the answer at decision point 224 is "no", the program returns to block 232.
Then, it is determined whether TW<LL. If the answer is "yes", the program branches to block 234, where the indicator light 50 in the controller 22 is illuminated and the sample and diluent are diluted to achieve the previously set dilution factor f. It is displayed that the weight is less than the specified minimum weight set by the minimum weight control device 55. The program then proceeds to block 236 where a memory element in controller 22 is set by switch 28 to prime the system for another diluent. The program then proceeds to a stop point 238 that terminates all operations in the program. If the answer at decision point 232 is "no", the program proceeds to block 240 where pump 42 is turned on and supply valve 34 is opened. The pump then pressurizes the diluent 36 against the container at a greater flow rate through the supply valve 34 than possible through the valve 46. The program then proceeds to block 242 where the BCD output from the weigher 12 of the combined weight of diluent and sample is read. The program then proceeds to decision point 244 where a determination is made whether the value (TW-W>10).
If the answer is "no", the program cycles again to block 242 and reaches decision point 244, where the calculation (TW-W>10) is performed.
As long as (TW-W>10), the valve 34 opens,
The highest flow rate of dilution into the container occurs.
The program continues to cycle until (TW-W=10), at which time the program branches to block 246 where supply valve 34 is closed and valve 46 is opened. At this time, the flow rate to vessel 20 is increased by a factor of 10 as a result of the lower flow rate of valve 46 compared to supply valve 34.
will be reduced only. Next, the program starts with block 2.
Proceeding to 48, the total weight W of the sample and diluent is read from the weigher 12. The program then advances to decision point 250, where it is determined whether (TW-W1). If the answer is "no"
If so, the program cycles again to block 248. If the answer is yes, the program proceeds to block 252 where the valve is turned on for 0.2 seconds.
This causes the power to be turned off for 1.8 seconds. The program proceeds to block 254 where the sample and diluent loads are read from the weigher 12. At this time, the program advances to decision point 256, where (TW=
A judgment is made as to whether W). If the answer is "no", the program returns to block 252 where valve 46 is again opened and closed. The program continues to cycle until (TW=W), at which time the program advances to block 258 where valve 46 is closed and supply valve 34 is maintained in its previously closed condition. At this time, a dilution factor f of the predetermined weight of diluent is achieved, and the total weight of sample and diluent is equal to TW. The program then proceeds to block 260 where the pump 42 is shut off, the ready indicator light on the controller 22 is illuminated, and the controller's memory components are reset. At this time, the program advances to stopping point 262, where no abnormal program operations occur.

FIG. 3 is an overall diagram illustrating a second embodiment 300 of the present invention. This second embodiment is the same as the first embodiment of the invention shown in FIG. 1, except that the device for controlling the flow of diluent is different. Identical parts in FIGS. 1 and 3 are designated by the same reference numbers. In a second embodiment of the invention, the flow of diluent between the reservoir and the container is controlled by starting and stopping pump 302, excluding first and second supply valves 34 and 46 of FIG. Ru. The pump may be configured to operate in any manner as long as it stops pumping fluid immediately upon receiving a stop command from the controller 22 on the high speed pump control line 304 and/or the low speed pump control line 306. A type of pump may also be used. There are many types of pumps with this capability.
The preferred type of pump is the Master Flex manufactured by Cole-Parmer Corp. of Chicago, Illinois, USA.
This is a peristaltic pump that can be of type C-7500-00. This peristaltic pump is desirable because it can be controlled to immediately stop pumping fluid. In order to achieve an accurate dilution that closely approximates a predetermined dilution factor f, the present invention provides:
(TW-W=0), it is necessary to immediately stop the flow of fluid into the container 20. In the present example, reciprocating pumps, centrifugal pumps, rotary pumps, and other types of pumps with relatively large inertia between pumping actions are used when these pumps are connected to the controller 22.
It cannot be used unless it has a valve action that makes it possible to immediately stop the flow of fluid upon receiving a stop command. Without valving to immediately stop the diluent flow, the inertia of the active pump would cause continued pumping of the diluent after the stop command is applied, resulting in a dilution factor f. This will result in a dilution up to a dilution factor f greater than .

The second embodiment uses a relatively large flow rate when the value is (TW-W>10) and in a similar manner to the two valve mechanism of the first example, and when the value is (0<
It includes a pump 302 that can be controlled to pump at two different flow rates, such that a relatively small volume is used when TW-W>10).

The microprocessor flowchart as shown in FIG. 2 can also be applied to the second embodiment. The only difference between these first and second embodiments is that in the second embodiment the supply valves 34 and 36 are omitted and the signal to control the diluent flow is routed directly to the pump 302. It is given to

DESCRIPTION OF THE OPERATION The operation of the present invention for diluting a sample of ethanol with a 50% by weight (f=0.5) solution of water is summarized as follows. Maximum and minimum weight values
UL and LL were previously set by the maximum and minimum weight controllers 53 and 55 of the controller 22 and shall not guarantee shutdown of the device. The dilution factor f is set by the dilution factor selection device 24 to a value of 0.5. Container 20 is bread 18
Once placed, the container weight control device 14 is energized to return the BCD output of the weigher 12 to zero. A sample of ethanol is then placed in container 20 and automatic supply switch 26 is turned on. from the weighing machine
The BCD output specifies that the sample is 100g.
The formula for calculating the value TW, namely Weight of sample/f=100g/0.5=200g, proves that the combined weight of ethanol and water to obtain a dilution factor f of 0.5 is 200g.
Pump 42 is immediately energized and quick feed valve 34 is opened. Next, the pump starts and water is supplied to valve 3 until the total weight of water and ethanol is 190g.
4 to vessel 20, at which time the program closes supply valve 34 and opens slow valve 46 to reduce the rate of water charging to vessel 20. When the weights W of ethanol and water are equal to 199g,
Valve 46 is repeatedly opened for 0.2 seconds and closed for 1.8 seconds. Pump 4 until the weight of water and ethanol is equal to 200g, which is equal to the previously calculated value TW.
2 continues to pump water into the container via the pulsating valve 46. Pump 42 is then shut off and valve 46
is closed to complete the dilution operation.