JPH04314455A - Roller pump - Google Patents

Abstract

PURPOSE:To make measuring errors unlike to occur by adjusting developing positions of a suction pressure. CONSTITUTION:This roller pump is provided with a tube 6 which has a suction port 8 at one end while having a discharge port 7 at the other end thereof and a rotor 1 which rotates squeezing the tube 6 to create a suction pressure at the suction port 8 in the rotation of the rotor 1. In the roller pump of such a type, a sensor 4 for detecting position is provided to detect the position of rotation of the rotor 1 and a sucking operation is controlled based on a detection output from the sensor 4 for detecting positions so that the position of the rotor 1 is constant at the start of suction.

Description

[Detailed description of the invention]

[Purpose of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roller pump that suctions or discharges liquid by rotating a rotor while crushing a tube.

0002

[Prior Art] A roller pump that can create positive pressure in the rotational direction of the rotor (tube extrusion side) and negative pressure in the opposite direction by rotating the rotor while crushing the tube can be detected in, for example, a blood cell counter. It is used when drawing diluted blood into a tube to count blood cells. During this counting, it is necessary to aspirate diluted blood into the detection tube with a constant suction pressure in order to improve the accuracy of blood cell counting. However, in this roller pump, the moment when the rotor presses the tube, that is, from the time when the rotor 1 hits the tube 6 as shown in FIG. 7 until the tube 6 is completely pressed by the rotor 1 as shown in FIG. In addition, since some pressure is also applied to the suction port 8 side, a state of low suction pressure occurs, leading to pressure fluctuations. Therefore, in the past, an air chamber was provided on the suction side to minimize fluctuations in suction pressure. This air chamber is connected to the suction port 8 and can communicate with the atmosphere via a solenoid valve.

0003

[Problems to be Solved by the Invention] However, in conventional roller pumps, even if an air chamber is provided on the suction side, some fluctuations in suction pressure remain, and as shown in FIG. Since the pressure fluctuation P1 occurs arbitrarily during this period, there is a problem in that, for example, an error occurs in the quantitative determination during blood cell counting, and the reproducibility of the measured value is poor.

The present invention was proposed in order to solve the above-mentioned conventional problems, and an object of the present invention is to provide a roller pump that aligns the appearance positions of pressure fluctuations and makes measurement errors less likely to occur. [Structure of the invention]

[0005]

[Means for Solving the Problems] In order to achieve this object, the present invention includes a tube having a suction port at one end and a discharge port at the other end, and a rotor that rotates while crushing this tube. A roller pump that creates suction pressure at the suction port when the rotor rotates is equipped with a position detection sensor that detects the rotational position of the rotor, and based on the detection output from this position detection sensor, when suction starts. The invention is characterized in that the suction operation is controlled so that the position of the rotor is kept at a constant position.

[0006]

[Operation] According to the above-mentioned configuration, since the position of the rotor can be detected by the position detection sensor, the suction operation can be started from a constant rotational position of the rotor, and slight changes in suction pressure can always be detected at a fixed rotational position. can be caused in position.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the roller pump according to the present invention will be described in detail with reference to the drawings. An embodiment of this roller pump is shown in FIGS. 1 to 3. In these figures,
A semicircular light-shielding plate 3 is attached to the rotating shaft 2 of the rotor 1 of this roller pump on the back side, and a position detection sensor 4 made of a photocoupler is mounted on the pump body so as to straddle this light-shielding plate 3. It is attached to the back of 5. By detecting the light shielding plate 3 using the position detection sensor 4, the rotational position of the rotor 1, which rotates while crushing the tube 6, can be detected. Here, the extrusion side of the tube 6, which is the rotational direction of the rotor 1, is the discharge port 7, and the opposite side is the suction port 8. Therefore, based on the detection output from the position detection sensor 4, the position of the rotor 1 at the start of measurement can be controlled to be constant, and slight changes in suction pressure that occur during measurement can be controlled for each measurement. can be made equal. Note that rotor 1 at the start of measurement
The position may be any position as long as it is constant.

FIG. 4 shows an example in which a roller pump having this configuration is used as a detection tube of a hemocytometer. In this figure, a pump drive circuit 10 controlled by a control circuit 9 outputs a drive signal to the roller pump. The output signal from the position detection sensor 4 is input to the control circuit 9 via the sensor circuit 11. Air chamber 1 connected to suction port 8
The second electromagnetic valve 13 is opened and closed by an opening/closing signal from the electromagnetic valve drive circuit 14. Further, output signals from a first water level sensor 16 provided on the lower side of the detection tube 15 and a second water level sensor 17 provided on the upper side are inputted to the control circuit 9 via the sensor circuit 11.

In this configuration, the roller pump is rotated at high speed at the same time as the switch to start measurement is turned on, and the solenoid valve 13 is opened at N1 to open the air chamber 12 to the atmosphere, as shown in FIG. Ru. Subsequently, when the position of the rotor 1 is detected by the position detection sensor 4 at N2, the solenoid valve 13 is closed and the internal pressure of the pump is reduced. Along with this, the diluted blood 19 in the cup 18 is sucked up into the detection tube 15, and when it is sucked up to the first water level sensor 16 position at N3, the pump is switched to be driven at low speed and blood cell counting starts. be done. N4
When a detection signal is output from the second water level sensor 17, the counting operation ends. The solenoid valve 13 is then briefly opened and the air chamber 12 is opened to the atmosphere. In this way, in this roller pump, the position of the rotor 1 at the start of measurement can be kept at a constant position, so that the position where the slight change in suction pressure P0 that occurs during measurement appears will vary from measurement to measurement, as shown in FIG. be equal. As a result, the suction pressure at t1 at the start of measurement and at t2 at the end of measurement becomes constant for each measurement, improving the reproducibility of quantitative determination and the reproducibility of measured values.

0010

Effects of the Invention As explained above, according to the present invention, since the rotational position of the rotor is kept constant at the start of suction, a slight suction pressure appears at the moment the rotor crushes the tube. The influence of changes in position can be suppressed to a low level, and the reproducibility of measured values in various measurements can be improved.

[Brief explanation of drawings]

FIG. 1 is a side view showing an embodiment of a roller pump according to the present invention.

FIG. 2 is a rear view of the roller pump of FIG. 1.

FIG. 3 is a front view of the roller pump of FIG. 2.

FIG. 4 is a configuration diagram of an apparatus showing an example in which the roller pump according to the present invention is applied to a blood cell counting apparatus.

FIG. 5 is a timing diagram showing the operation of the blood cell counting device of FIG. 4.

FIG. 6 is a characteristic diagram showing changes in suction pressure of this roller pump.

FIG. 7 is an explanatory diagram for explaining the occurrence of fluctuations in suction pressure.

FIG. 8 is an explanatory diagram for explaining the occurrence of fluctuations in suction pressure.

FIG. 9 is a characteristic diagram showing how the suction pressure of a conventional roller pump changes.

[Explanation of symbols]

1 rotor
2 Rotating shaft 3 Light shielding plate
4 Position detection sensor 5 Pump body
6 Tube 7 Discharge port
8 Suction port 9 Control circuit
10 Pump drive circuit 12 Air chamber
13 Solenoid valve 14 Solenoid valve drive circuit

Claims (1)

[Claims] Claim 1: A tube having a suction port at one end and a discharge port at the other end, and a rotor that rotates while crushing this tube, and when the rotor rotates, it creates suction pressure at the suction port. The roller pump includes a position detection sensor that detects the rotational position of the rotor, and controls the suction operation so that the rotor is at a constant position when suction is started based on the detection output from the position detection sensor. A roller pump characterized by: