JP2013003135A - Precision liquid dispenser - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dispense liquid into a measurement container at a high speed and with high accuracy.SOLUTION: A dispenser is used for precisely dispensing liquid in a supply container into the measurement container. The precision liquid dispenser includes: an air blower as a roughly weighing feeding pump connected to the supply container with a tube; a piezoelectric element type pump as a precisely weighing feeding pump connected between the supply container and the weighing container with tubes; and a precision electronic balance which measures the weight of liquid injected into the measurement container.

Description

  The present invention relates to a precision liquid measurement and dispensing apparatus.

  The precision liquid dispensing apparatus is required to accurately inject the liquid in the supply container into the measuring container in a short time. As one of liquid pumps for dispensing the liquid in the supply container into the measuring container, a liquid pump is used in which a piston is driven by a motor by combining a cylinder and a piston.

  JP 2000-329771 A

  The liquid can be dispensed into the measuring container at high speed and with high accuracy.

  In a dispensing device for accurately dispensing the liquid in a supply container into a measuring container, the supply container is equipped with an air blower connected to the supply container by a tube as a coarse weighing pump. A precision liquid component comprising a piezoelectric element type pump as a precision weighing pump connected by a tube between containers, and a precision electronic balance for measuring the weight of the liquid injected into the weighing container. Note device.

  According to the present invention, as a liquid pump used for liquid dispensing, an air blower is used for a coarse amount, and a piezoelectric element type pump is used for a minute amount, thereby enabling precise liquid dispensing in a short time.

Explanatory drawing showing the configuration of the precision liquid dispensing device The process drawing of precision liquid dispensing equipment is shown.

In FIG. 1, 1 is an air blower, 2 is a supply container, 3, 4, 5, and 6 are tubes, 7 is a piezoelectric element type pump, 8 is a measuring container, and 9 is a precision electronic balance. .
(1) First, the air blower 1 is driven to inject air into the supply container 2 through the tube 3. By this air pressure, the liquid in the supply container 2 is passed through the tube 4 and most of the required liquid amount is measured into the measuring container 8. To discharge.
{Circle around (3)} During this time, the piezoelectric element type pump 7 for supplying the precise weighing is simultaneously driven to inject the liquid in the measuring container into the measuring container 8 through the tubes 5 and 6.
(4) Next, the air blower 1 for supplying the coarse weight is stopped immediately after the required liquid amount, and only the piezoelectric element type pump 7 for supplying the precise weight is driven, and the precision electronic balance 9 is used. Weigh accurately to achieve the required liquid volume.
(5) It should be noted that the piezoelectric element type pump 7 for supplying the precise weighing can discharge a predetermined minute amount by driving every pulse, and can accurately supply the weighing in the unit of pulse with respect to the required liquid amount. is there.
{Circle over (6)} Next, the operation and method of precision weighing by the piezoelectric element type pump 7 for supplying the precision weighing in units of pulses will be described. In the pulses applied to the piezoelectric element type pump 7 for supplying the precise weighing, the method of supplying the weighing by increasing / decreasing the number of pulses per unit time, and the time width of the pulse, the driving voltage, or increasing / decreasing simultaneously It is possible to quickly and precisely control a small amount of liquid by a method of feeding by weighing.
(7) Further, as automation of the liquid dispensing, the liquid weight measurement data sequentially output from the precision electronic balance is taken into a personal computer (hereinafter referred to as a personal computer), and the difference from the required liquid amount by the personal computer. The most of the amount of liquid injected into the measuring container is required to inject a large amount of liquid by driving both the coarse weigh supply air blower and the precise weigh-feed piezoelectric element pump. In the immediate vicinity of the liquid volume, stop the air supply blower for coarse weighing supply, drive only the piezoelectric element pump for precision weighing supply, and stop the piezoelectric element pump for precision weighing supply when the difference is zero This makes it possible to automate the dispensing of the required liquid amount.
FIG. 2 shows a control flow of an air blower for dispensing liquid from a supply container to a measuring container, and a piezoelectric element type pump. The sequence will be described below.
(1) First, the dispensing process is started by driving the air blower and piezoelectric element pump.
(2) Next, measure the required amount while continuing dispensing, and monitor the difference from the dispensing amount.
(3) Monitor whether the difference is within α%. Α is preset from the controllability of the air blower.
(4) When the difference falls within α%, the inside of the supply container is depressurized in preparation for stopping the air blower.
(5) Monitor whether the difference is within β%. Β is preset from the controllability of the air blower.
(6) Subsequently, the air blower is stopped, only the piezoelectric element pump is operated, the measurement is continued, and the difference is monitored.
The remaining dispensing volume is calculated from the dispensing volume when the air blower is stopped, and the required number of pulses is calculated from the pulse duration and pulse voltage conditions of the piezoelectric element type pump drive.
(7) Monitor the difference by measuring the number of pulses and monitor if the difference is zero.
(8) Dispensing is stopped when the difference becomes zero.

1. 1. Air blower 2. Supply container Tube 4. Tube 5. Tube 6. Tube 7. 7. Piezoelectric pump 8. Weighing container Precision electronic balance

Claims (5)

In an apparatus for precisely dispensing the liquid in the supply container into the weighing container,
The supply container is provided with a coarse weighing pump connected by a tube, and is provided with a precision weighing supply pump connected by a tube between the supply container and the measurement container, and injected into the measurement container. A precision liquid dispensing apparatus comprising a precision electronic balance for weighing a liquid weight. The precision liquid dispensing apparatus according to claim 1,
A precision liquid dispensing apparatus, wherein an air blower is used as the coarse weighing pump and a piezoelectric element type pump is used as the precision weighing pump. The precision liquid dispensing apparatus according to claim 2,
Most of the amount of liquid injected into the measuring container is dispensed using both the air blower and the piezoelectric element type pump, and the air blower is stopped in the immediate vicinity of the required liquid amount, and only the piezoelectric element type pump is used. A precision liquid dispensing apparatus characterized by being used to dispense a small amount of liquid into the measuring container. The precision liquid dispensing apparatus according to claim 3,
The drive pulse of the piezoelectric element pump is to drive the piezoelectric element pump by increasing or decreasing the number of pulses per unit time, the time width of the pulse, and the voltage of the pulse, or a combination thereof. A precision liquid dispensing device. The precision liquid dispensing apparatus according to claim 4,
As automation of the liquid dispensing, the liquid weight measurement data sequentially output from the precision electronic balance is taken into a personal computer (hereinafter referred to as a personal computer), and the difference from the required liquid amount is sequentially taken out by the personal computer. Most of the liquid injection amount to the measuring container is driven by simultaneously driving the air blower and the piezoelectric element type pump to inject a coarse amount of liquid, and the air blower is stopped immediately after the required liquid amount to A precision liquid dispensing apparatus that dispenses a required amount of liquid into the measuring container so that the difference is zero by driving only the pump.

Images