JP2012217894A - Liquid medicine injection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid medicine injection device which can inhibit injection fault of a liquid medicine.SOLUTION: This liquid medicine injection device 1 includes a diaphragm pump 11 which injects the liquid medicine reserved in a liquid medicine vessel 10 into water running through a main tube 100, a first flow rate sensor 14 for detecting the flow rate of the liquid medicine to be injected into the main tube 100 by the diaphragm pump 11, a second flow rate sensor 15 for detecting the flow rate of the water flowing through the main tube 100, and a control unit 18 which calculates the concentration of the liquid medicine injected into the water, based on the flow rate detected by the first flow rate sensor 14 and the second flow rate sensor 15, and controls the amount of the liquid medicine to be injected by the diaphragm pump 11 so as to achieve a target concentration of the liquid medicine.

Description

  The present invention relates to a chemical liquid injector that injects a chemical liquid into water flowing through a pipe using a diaphragm pump.

  A technique is known in which well water is sterilized by filtering the iron, manganese ions, etc. contained in the well water with a filtration device and injecting a chemical solution with the chemical solution injection device, and the well water is used for drinking water or the like ( For example, see Patent Document 1).

  The chemical solution injection device sterilizes well water and deposits iron contained in the well water by injecting sodium hypochlorite, which is a chemical solution, into the well water using a diaphragm pump.

JP 2006-81976 A

  The above-described chemical injection device has the following problems. In other words, the chemical solution injection device quantitatively injects the chemical solution into the well water, but there is a possibility that the concentration of the chemical solution in the well water may vary due to a change in the flow rate of the well water.

  In addition, sodium hypochlorite used in chemicals is an unstable vaporizable liquid, and when stored in a chemical tank, there is a problem that its characteristics change after a certain period of time in a high temperature environment or the like. .

Specifically, sodium hypochlorite promotes self-decomposition when the storage temperature reaches 25 ° C. or higher, and has the chemical formula 2NaClO → 2NaCl + O _2.
As shown in FIG. 4, there is a problem that oxygen gas is generated and the effective chlorine concentration is lowered.

  Further, when a certain amount of the generated oxygen gas is accumulated in the diaphragm pump, a so-called gas lock may occur in which the chemical liquid is not compressed by the reciprocating motion of the diaphragm and the oxygen gas is compressed. These problems cause the occurrence of a decrease in the concentration of the chemical solution, and cause a poor injection of the chemical solution.

  Then, an object of this invention is to provide the chemical | medical solution injection | pouring apparatus which can prevent the injection | pouring defect of a chemical | medical solution.

  In order to solve the above-described problems and achieve the object, the chemical liquid injector of the present invention is configured as follows.

  As one aspect of the present invention, in a chemical injection device that injects a chemical into water flowing through a main, a diaphragm pump that injects a chemical stored in a chemical tank into the main is injected into the main by the diaphragm pump. From the flow rate detected by the first flow rate sensor for detecting the flow rate of the chemical solution, the second flow rate sensor for detecting the flow rate of the water flowing through the main pipe, the flow rate detected by the first flow rate sensor and the second flow rate sensor, A controller that calculates the concentration of the chemical solution injected into water and controls the amount of the chemical solution injected from the diaphragm pump in order to set the calculated concentration of the chemical solution as a target concentration.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the chemical | medical solution injection | pouring apparatus which can prevent the injection | pouring defect of a chemical | medical solution.

Explanatory drawing which shows typically the structure of the chemical injection device which concerns on one embodiment of this invention. Sectional drawing which shows the structure of the diaphragm pump used for the same chemical injection device.

Hereinafter, a chemical liquid injector 1 according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2.
FIG. 1 is an explanatory view schematically showing a configuration of a chemical liquid injector 1 according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view showing a configuration of a diaphragm pump 11 used in the chemical liquid injector 1.

  The chemical solution injection device 1 is configured to be able to inject a chemical solution into a main pipe 100 that supplies raw water (well water) supplied from a supply source such as a well by a water supply pump to a filtration device. In addition, sodium hypochlorite is used for a chemical | medical solution. Moreover, as for the main pipe 100, the primary side is connected to the water supply pump, and the secondary side is connected to the filtration apparatus.

  The chemical liquid injector 1 includes a chemical tank 10, a diaphragm pump 11, a first connection pipe 12, a second connection pipe 13, a first flow sensor 14, a second flow sensor 15, a thermistor 16, and concentration measurement. A device 17 and a control device 18 are provided.

  The chemical solution tank 10 is formed of a resin material, and is formed so that a predetermined amount of chemical solution can be stored therein. The chemical | medical solution tank 10 has the 1st connection pipe 12 connected to the lower surface. The chemical tank 10 is closed by a lid or the like so that air can move.

  The diaphragm pump 11 includes a pump unit 21 and a motor unit 22.

  The pump unit 21 includes a pump casing 31, a piston 32, a biasing member 33, and a diaphragm 34. The pump casing 31 has a pump chamber 35 therein. The pump casing 31 includes a suction port 36 continuous with the pump chamber 35, a discharge port 37, and a check valve 38 provided in each of the suction port 36 and the discharge port 37.

  The piston 32 is formed so as to be able to reciprocate by the motor unit 22. One end of the piston 32 is located in the pump casing 31, and the other end is located in the motor unit 22. As shown in FIG. 2, the piston 32 is formed with a fastened portion such as a female screw to which a diaphragm 34 can be attached, for example. The piston 32 has a seat 39 on the other end side.

  The biasing member 33 is a coil spring, and the piston 32 is inserted through the biasing member 33 and is disposed between the seat 39 of the piston 32 and the outer surface of the pump casing 31. The urging member 33 urges the piston 32 toward the motor, thereby bringing the end of the other end of the piston 32 into contact with the outer peripheral side of an eccentric cam 43 described later.

  The diaphragm 34 is a thin film formed of an elastic material. The diaphragm 34 is located in the pump chamber 35, covers one end of the piston 32, and is configured to be reciprocable by the piston 32. Specifically, as shown in FIG. 2, the diaphragm 34 is provided with a fastening member such as a male screw that is fastened to the fastened portion of the piston 32 at the center thereof, and the fastening member fastens to the fastened portion. Thus, the central portion is fixed to the end portion on one end side of the piston 32. Further, the outer periphery of the diaphragm 34 is fixed to the pump casing 31 so that the pump chamber 35 is liquid-tight. That is, the diaphragm 34 forms a part of the inner wall of the pump chamber 35, and is deformed by the reciprocating motion of the piston 32, thereby increasing or decreasing the volume of the pump chamber 35, and sucking and discharging the chemical solution in the pump chamber 35. .

  The motor unit 22 includes a stepping motor 42 having a rotation shaft 41 and an eccentric cam 43 fixed to the rotation shaft 41. The stepping motor 42 is connected to the control device 18 via the signal line S. The stepping motor 42 is formed so as to be able to output a high torque capable of reciprocating the piston 32 by an eccentric cam 43.

  The eccentric cam 43 is formed so that the difference between the maximum radius and the minimum radius of the outer surface from the rotation center thereof is equal to the reciprocating distance of the piston 32. The eccentric cam 43 is provided with a portion having a maximum radius and a minimum radius at a point-symmetrical position around the rotation center.

  For example, the eccentric cam 43 is provided at intervals of 180 degrees at the minimum radius and the maximum radius, and the eccentric cam 43 is rotated 180 degrees from the minimum radius to move the piston 32 toward the pump chamber 35. . Further, the eccentric cam 43 is rotated 180 degrees from the portion having the maximum radius, so that the piston 32 biased toward the eccentric cam 43 by the biasing member 33 moves toward the eccentric cam 43 along the outer peripheral surface thereof. Move.

  The first connecting pipe 12 connects the chemical tank 10 and the suction port 36. The 1st connection pipe 12 has the 1st flow sensor 14 in the middle part. The second connecting pipe 13 connects the discharge port 37 and the main pipe 100.

  The first flow sensor 14 is connected to the control device 18 via a signal line S. The first flow rate sensor 14 is formed so as to be able to detect the flow rate of the chemical liquid moving from the chemical liquid tank 10 to the suction port 36.

  The second flow rate sensor 15 is connected to the control device 18 via a signal line S. The second flow rate sensor 15 is the main pipe 100 and is provided on the primary side of the connection portion to which the second connecting pipe 13 is connected. The second flow rate sensor 15 is formed so as to be able to detect the flow rate of raw water flowing through the main pipe 100.

  The thermistor 16 is formed so as to be able to detect any of the outside air temperature, the temperature of the chemical solution tank, or the temperature of the chemical solution. In the present embodiment, the thermistor 16 will be described using a configuration capable of detecting the outside air temperature.

  The concentration measuring device 17 is connected to the control device 18 via a signal line S. The concentration measuring device 17 is formed so as to be able to detect the concentration of the chemical injected into the raw water flowing in the main pipe 100. The concentration measuring device 17 is provided on the secondary side of the connecting portion to which the second connecting pipe 13 is connected and on a pipe line that is separated by a predetermined distance. The predetermined distance is a distance at which the chemical solution in the raw water becomes uniform when the injected chemical solution is mixed with the raw water, that is, a distance at which the concentration is stabilized. For example, the concentration measuring device 17 is about 10 m. It is provided apart from the connection part. For this reason, the concentration measuring device 17 is provided on a pipe line that is separated from the connecting portion by a predetermined distance.

  The control device 18 is connected to the stepping motor 42, the first flow sensor 14, the second flow sensor 15, the thermistor 16, and the concentration measuring device 17. The control device 18 has a storage unit 51. The control device 18 is configured to be able to switch between driving and stopping of the stepping motor 42 and to change the rotation speed of the stepping motor 42. The memory | storage part 51 has memorize | stored the temperature which generation | occurence | production of gas accelerates | stimulates by the self-decomposition of a chemical | medical solution, and the external temperature in this embodiment as a threshold value.

The control device 18 has at least the following functions (1) to (4).
(1) The concentration of the chemical solution in the raw water is calculated from the injection amount of the chemical solution detected by the first flow sensor 14 and the second flow sensor 15 and the flow rate of the raw water, and the stepping motor 42 is configured so that the concentration becomes the target concentration. A function that performs feedback control to vary the rotation speed.

  (2) The concentration calculated from the flow rate (injection amount) of the chemical solution detected by the first flow rate sensor 14 and the second flow rate sensor 15 and the flow rate of the raw water in the main pipe 100 and the concentration detected by the concentration measuring device 17 A function of varying the rotation speed of the stepping motor 42 based on information detected by the concentration measuring device 17 when there is a difference.

(3) A function of driving the stepping motor 42 at the maximum rotational speed for several seconds when the temperature detected by the thermistor 16 is equal to or higher than the threshold value.
(4) A function of injecting a chemical solution smaller than a predetermined amount into raw water for a predetermined time after driving the stepping motor 42 at the maximum speed when the temperature detected by the thermistor 16 is equal to or higher than a threshold value.

  The chemical injection device 1 configured as described above drives the stepping motor 42 based on the information detected by the first flow sensor 14, the second flow sensor 15, the thermistor 16, and the concentration measurement device 17, and supplies the chemical to raw water. Inject.

  More specifically, the control device 18 drives the stepping motor 42 when raw water is supplied from the primary water supply pump of the main pipe 100. By driving the stepping motor 42, the eccentric cam 43 rotates and the piston 32 reciprocates.

  By the reciprocation of the piston 32, the diaphragm 34 is deformed, the volume of the pump chamber 35 is changed, and the pressure of the chemical solution in the pump chamber 35 is increased or decreased. Further, the check valve 38 is alternately opened and closed by a change in pressure in the pump chamber 35, the chemical solution in the pump chamber 35 is pumped to the secondary side, and the chemical solution is injected into the main pipe 100.

  At this time, as a function (1), the control device 18 uses the injection amount of the chemical liquid detected by the first flow rate sensor 14, the concentration calculated from the flow rate of the raw water detected by the second flow rate sensor 15, and the target concentration. And the stepping motor 42 is varied so that the calculated density becomes the target density.

  Specifically, the control device 18 calculates the concentration at the time of detection from the flow rate (injection amount) of the chemical solution detected by the first flow rate sensor 14 and the flow rate of raw water detected by the second flow rate sensor 15. . The control device 18 compares the calculated density with the target density stored in the storage unit 51. When the calculated density is substantially the same as the target density, the control device 18 drives the stepping motor 42 without changing its rotational speed.

  When the calculated density and the target density are different, the control device 18 varies the rotational speed of the stepping motor 42, and the rotational speed of the stepping motor 42 until the calculated density and the target density become substantially the same. Is variable.

  Even when the calculated concentration and the target concentration are substantially the same, the control device 18 calculates the concentration from the flow rate of the continuously detected chemical and raw water and compares it with the target flow rate. Thus, the control device 18 performs feedback control from the flow rates detected by the first flow rate sensor 14 and the second flow rate sensor 15 and the concentration of the target chemical solution.

  Further, the control device 18 functions, as function (2), the concentration of the chemical solution in the raw water detected by the concentration measurement device 17 and the concentration of the chemical solution injected by the function (1), that is, the first flow rate sensor 14 and the first flow rate sensor 14. 2. It is determined whether or not there is a difference between the concentration calculated from the flow rate of the chemical solution detected by the flow rate sensor 15 and the raw water.

  If there is no difference in the density, the control device 18 continues to drive the stepping motor 42 by function (1). If there is a difference in the concentration, the control device 18 controls the stepping motor 42 based on the concentration detected by the concentration measuring device 17.

  As a function (3), the control device 18 detects the temperature with the thermistor 16 while the diaphragm pump 11 is being driven. When the detected temperature is equal to or higher than the threshold, the control device 18 operates the stepping motor 42 at the maximum rotation speed for several seconds, for example, about 10 seconds. The control device 18 operates the stepping motor 42 at the maximum rotation speed for several seconds, and then functions (4) as a function (4) so that the concentration is lower than the target concentration for a predetermined time. Inject a small amount of chemical into raw water. That is, the control device 18 drives the stepping motor 42 at a low speed so that the density becomes lower than the target density after the stepping motor 42 is operated for several seconds at the maximum rotational speed.

  For example, as the function (4), the control device 18 adjusts the time for performing the maximum rotational speed operation of the function (3) and the chemical liquid smaller than a predetermined amount with respect to the flow rate of the raw water of the function (4). The injection amount of the chemical liquid that is expected from the total time of operation is substantially the same as the injection amount of the chemical liquid that is injected for the same time as the above-described total time in function (1) or function (2).

  In other words, the control device 18 adjusts the amount of the chemical liquid injected by the diaphragm pump 11 as the function (4), so that the chemical liquid while the diaphragm pump 11 is driven by the function (3) and the function (4) is adjusted. The injection amount is prevented from becoming an excessive injection amount. The function (3) and the function (4) may be performed every certain time, for example, every few hours.

  According to the chemical liquid injector 1 configured as described above, the chemical liquid to be injected can be adjusted based on the information detected by the first flow sensor 14 and the second flow sensor 15. In addition, when the concentration of the chemical solution calculated from the flow rates detected by the first flow sensor 14 and the second flow sensor 15 is compared with the concentration detected by the concentration measuring device 17, a difference is found in the concentration. Controls the stepping motor 42 based on the concentration detected by the concentration measuring device 17.

  As a result, the chemical solution injection device 1 is configured so that the chemical solution injected into the raw water due to the error of the first flow rate sensor 14 and the second flow rate sensor 15, the error of the pump unit 21, and the decrease in the effective chlorine concentration due to the self-decomposition of the chemical solution. It is possible to correct the density. For this reason, it becomes possible to control the injection amount of the chemical solution with high accuracy with a simple configuration.

  Further, the chemical injection device 1 drives the stepping motor 42 at the maximum rotation speed and the diaphragm 34 according to the temperature detected by the thermistor 16, thereby causing gas generated in the pump chamber 35 by self-decomposition of the chemical. Can be prevented from accumulating. By preventing gas accumulation in the pump chamber 35, it is possible to prevent gas lock generated by the gas accumulation, and it is possible to prevent poor chemical injection.

  Also, the chemical solution injection device 1 performs an operation for preventing gas lock at every predetermined time, so that even if the chemical solution is exposed to a temperature that promotes self-decomposition for a long time, the pump chamber It is possible to prevent gas from accumulating in 35.

  Furthermore, the chemical solution injection device 1 prevents the chemical solution from being poorly injected by making the injection amount of the chemical solution smaller than usual after preventing the gas accumulation, in other words, the chemical solution is excessively injected into the raw water. It becomes possible to prevent.

  As described above, according to the chemical liquid injector 1 according to the embodiment of the present invention, it is possible to provide a chemical liquid injector that can prevent poor chemical injection.

  The present invention is not limited to the above embodiment. For example, in the above-described example, by using the concentration measuring device 17, the concentration of the chemical solution calculated based on the detection information of the first flow rate sensor 14 and the second flow rate sensor 15 and the concentration measuring device 17 detects the concentration. Although the structure which controls the diaphragm pump 11 according to the difference with information was demonstrated, it is not limited to this.

  For example, when the concentration detected by the concentration measuring device 17 is different from the calculated concentration of the chemical solution in the raw water, the error is corrected, and the notification means provided in the control device or the like is used to notify the outside of the operator or the like. The structure which alert | reports that the said error has generate | occur | produced may be sufficient.

  Further, for example, a configuration without using the concentration measuring device 17 may be adopted. That is, in the case of a customer request or when a chemical solution in the chemical solution tank 10 is used or exchanged for a short time, the manufacturing cost of the chemical solution injection device 1 is reduced by adopting a configuration in which the concentration measuring device 17 is not provided. It becomes possible.

  Further, in the above-described example, the eccentric cam 43 has been described with the configuration in which the portions having the minimum radius and the maximum radius are provided with an interval of 180 degrees, but is not limited thereto. For example, the portions having the minimum radius and the maximum radius may be alternately provided at intervals of 90 degrees, or may be alternately provided at intervals of 45 degrees. In addition, various modifications can be made without departing from the scope of the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Chemical solution injection apparatus, 10 ... Chemical solution tank, 11 ... Diaphragm pump, 12 ... 1st connection pipe, 13 ... 2nd connection pipe, 14 ... 1st flow sensor, 15 ... 2nd flow sensor, 16 ... Thermistor, 17 ... Concentration measuring device 18 ... Control device 21 ... Pump unit 22 ... Motor unit 31 ... Pump casing 32 ... Piston 33 ... Biasing member 34 ... Diaphragm 35 ... Pump chamber 36 ... Suction port 37 ... Discharge port, 38 ... check valve, 39 ... seat part, 41 ... rotating shaft, 42 ... stepping motor, 43 ... eccentric cam, 51 ... storage part, 100 ... main pipe, S ... signal line.

Claims (5)

In the chemical injection device that injects the chemical into the water flowing through the main pipe,
A diaphragm pump for injecting the chemical stored in the chemical tank into the main pipe,
A first flow sensor for detecting a flow rate of the chemical liquid injected into the main pipe by the diaphragm pump;
A second flow sensor for detecting a flow rate of water flowing through the main pipe;
In order to calculate the concentration of the chemical liquid injected into the water from the flow rates detected by the first flow sensor and the second flow sensor, and to set the calculated concentration of the chemical liquid as a target concentration, A control device for controlling the amount of the chemical liquid injected from the diaphragm pump;
A chemical injection device characterized by comprising: The diaphragm pump is
A stepping motor having a rotating shaft;
An eccentric cam provided on the rotating shaft;
A piston that reciprocates by rotation of the eccentric cam;
A pump casing having a pump chamber;
A diaphragm that is provided in the pump chamber and changes a volume in the pump chamber by a reciprocating motion of the piston;
The chemical injection device according to claim 1, comprising: A thermistor capable of detecting the outside air temperature, the temperature of the chemical liquid tank or the temperature of the chemical liquid stored in the chemical liquid tank;
A storage unit that stores, as a threshold, a temperature at which gas generation is promoted by self-decomposition of the chemical solution;
When the temperature detected by the thermistor reaches the threshold, the control device drives the stepping motor for a predetermined time at a rotational speed higher than a rotational speed at which the chemical solution is injected to obtain the target concentration. The chemical injection device according to claim 2.   The control device is driven at a rotational speed higher than the rotational speed at which the chemical solution is injected to obtain the target concentration for a predetermined time, and is lower than the rotational speed at which the chemical solution is injected to obtain the target concentration. The chemical injection device according to claim 3, wherein the stepping motor is driven at a rotational speed for a predetermined time. A concentration measuring device for detecting the concentration of the chemical injected into the water;
The control unit, when there is a difference between the calculated concentration of the chemical solution and the concentration of the chemical solution detected by the concentration measurement device, based on the concentration of the chemical solution detected by the concentration measurement device The chemical injection device according to any one of claims 1 to 4, wherein the diaphragm pump is driven.

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