JPH04361170A - Apparatus for measuring charge quantity of liquid - Google Patents

Abstract

PURPOSE:To measure the drift charge characteristics of a liquid in a filter with good reproducibility by easy operation and to also measure the release charge characteristics of the liquid in the filter. CONSTITUTION:A charge detection pipe 11 charged by the contact or separation of a liquid sample, sample removing means 3,5 bringing the sample into contact with the charge detection pipe 11 and a net 12 and removing the same from them, a charge quantity measuring means 41 measuring the charge quantity of the charge quantity detection pipe 11 and a shield body 2 shielding the noise to the charge detection pipe 11 from the outside.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring the amount of charge of a liquid.

0002

2. Description of the Related Art In liquid transportation, filters are often used to remove solid impurities. This filter exhibits extremely high charging characteristics due to its large contact surface with liquid, and there have been cases of disasters in the past that are presumed to be caused by charging of the filter. By the way, electrification caused by filters is not well understood because the internal structure of the filter itself is complicated, and in order to know how static electricity is generated in the production process, it is necessary to actually measure it according to the handling conditions. Actual measurement of the amount of charge in this production process itself has the risk of causing discharge, and it is not possible to measure it while changing various conditions.
Therefore, there is a need for a measuring device that can be used experimentally. Conventionally, devices using full-scale tanks have been known as devices for measuring the amount of electrostatic charge of liquids that can be carried out experimentally. K
raemer, G. Schoen: PTB-Ber
icht, W-6, Physikalisch-Te
chnische Bundesanstalt. B
It was proposed by Runschweig (1976). This device has a filter built into the piping system.
The amount of charge on the liquid is measured by passing the liquid through the filter and measuring the flowing current generated in the filter at this time.

0003

[Problems to be Solved by the Invention] However, in measurement using this conventional device, the shape and material of the filter material and container are too complicated, and the sample liquid is used in circulation for measurement. There was a problem in that the characteristics changed and it was difficult to maintain the quality of the sample liquid, so the data varied widely and quantitative measurement results could not be obtained. Further, there was a problem in that the peel-off charging characteristics of the liquid could not be measured. The present invention solves the above-mentioned problems, and makes it possible to measure the flow charging characteristics of a liquid in a filter with good reproducibility through easy operations, and furthermore, to measure the exfoliation charging characteristics of a liquid in a filter. The purpose of the present invention is to provide a device for measuring the amount of charge of a liquid. Note that the peeling electrification characteristic refers to the electrification characteristic when the liquid is peeled off from the filter.

0004

[Means for Solving the Problems] The present invention includes a charged detector that is charged by contact and separation of a liquid sample, and a method for bringing the sample into contact with the charged detector and removing the sample from the charged detector. The present invention is characterized in that it includes a sample removing means, a charge amount measuring means for measuring the amount of charge on the charge detecting member, and a shielding member for blocking external noise from entering the charge detecting member.

[0005]

[Operation] First, a liquid sample is injected into the charged detection body, and the sample is suctioned by a suction device such as a vacuum pump that constitutes the sample removal means, so that the sample is brought into contact with the charged detection body and removed from the charged detection body. Remove. At this time, the charge detection body is charged with a flowing charge amount that is equal to and opposite in polarity to the charge amount generated on the sample due to contact and separation between the sample and the charge detection body. Further, a liquid sample is deposited inside the charged object, and the sample is suctioned by a suction device such as the vacuum pump to be removed from the charged object. At this time, the charge detection body is charged with a peel-off charge amount that is equal to and opposite in polarity to the charge amount generated on the sample when the sample is peeled from the charge detection body. At this time, the amount of charge on the charge detection body can be measured by the charge amount measuring means, and thereby the amount of flow charge and the amount of peeling charge that are equal to the amount of charge on the charge detection body can be measured.

[0006]

[Embodiment] In FIGS. 1 and 2 showing an embodiment of the liquid charge measuring device of the present invention, the charge detection tube 11 is made of, for example, SUS, with a diameter of 18 mm and a total length of 120 mm, as shown in FIG.
This tube is made of a steel bar made of No. 304 material and has a liquid injection part 11c, a liquid storage part 11d, and a liquid discharge part 11e formed by penetrating the inside of the charge detection tube 11 in the axial direction.

The liquid injection part 11c has a funnel shape with a length of 20 mm, with a diameter of 14 mm at one end of the charge detection tube 11 and a diameter of 10 mm at the terminal end of the liquid injection part 11c, and the liquid storage part 11d is a through hole with a constant diameter. It is a hole, and the liquid storage part 11d
The outlet has a funnel shape and has a length of about 60 mm so as to be connected to a liquid discharge part 11e which is a through hole with a diameter of 4 mm. Note that the length of the liquid discharge portion 11e is 40 mm.

Further, an insulating tube 13 (described later) is provided on the outer peripheral surface of the charge detection tube 11 corresponding to the portion where the liquid discharge portion 11e is formed.
A screw 11a that engages with the charge detection tube 11 is formed along the axial direction of the charge detection tube 11.
A charge amount detection terminal 11b is provided to which a lead wire 42 is connected to the charge amount detection meter 41.

For example, in the cylindrical insulating tube 13 made of an insulating material such as Teflon, one side surface 13b in the axial direction
A recess 13c having a circular planar shape and a bottom is formed in the recess 13c, and a screw 13a that engages with a screw 11a formed at one end of the charge detection tube 11 is provided in the inner peripheral surface of the recess 13c in the axial direction. formed along. On the other hand, a pipe 21 having the same inner diameter as the through hole with a diameter of 4 mm constituting the liquid discharge portion 11e of the charge detection tube 11 is engaged with the other axial end side surface 13d of the insulating tube 13, and the concave portion Bottom surface 13f of 13c
A through hole 13e with a diameter of 4 mm is formed between the pipe 21 and the pipe 21.

Charge detection tube 11 and insulation tube 13 explained above
This means that after the net 12 made of a material such as SUS304 and having a diameter approximately equal to the inner diameter of the recess 13c is placed on the bottom surface 13f of the insulating tube 13, an electrical charge is detected on the screw 13a of the recess 13c of the insulating tube 13. The screws 11a of the tube 11 are engaged, and the charge detection tube 11 is screwed into the recess 13c until the charge detection tube 11 presses the net 12, thereby being connected. By coupling the charge detection tube 11 and the insulating tube 13 in this way, liquid can be transferred between the liquid storage portion 11d and the like in the charge detection tube 13 and the piping 21 via the mesh 12 and the through hole 13e, and the insulation Since the tube 13 is an insulating material, the charge detection tube 11 and the net 1
2 and piping 21 are electrically insulated. Furthermore, the charge detection tube 11 and the insulating tube 13 are removable, and can be replaced with a mesh 12 having a different number of meshes, as will be described later. Note that the charging detection tube 11 can be attached to the insulating tube 13 by ordinary attachment methods such as packing or fitting via an O-ring other than screwing.

The pipe 21 is connected to a hollow sealed tank 3 made of metal via a valve 22 and a pipe 23 so as to be able to send liquid. The valve 22 is connected to, for example, a commercial AC 100V via a switch 24, and by operating the switch 24, the valve 22 can be opened and closed.

Charge detection tube 11 configured as described above,
The insulating tube 13, the piping 21, the valve 22, and the piping 23 are housed in a cylindrical container 2 having an inner diameter of 70.3 mm and a length of 350 mm and made of a conductive material such as metal.
is fixed to the tank 3. Further, the storage container 2 is grounded, and with this configuration, the storage container 2 shields the charge detection tube 11 and the like from electrical noise acting from the outside.

The tank 3 is a cylindrical container with an inner diameter of 65.9 mm and a length of 190 mm. The tank 3 is grounded so as not to generate electrical noise, and is connected to the piping 7.
1, valve 72, piping 73, gas cooler 4 and piping 74
is connected to the vacuum pump 5 so that air can be supplied thereto, and is connected to the atmosphere via a pipe 75a and a valve 75, and via a pipe 76a and a valve 76, respectively. The piping 71 and the piping 75a are connected to the circumferential side surface of the tank 3, the piping 76a is connected to the bottom plate of the tank 3, and the connection parts of the tank 3 and the piping 23, 71, 75a, and 76a are connected to the tank 3, respectively. The interior of the chamber is connected to the atmosphere in an airtight manner. Further, a vacuum gauge 77 is attached to the tank 3 for measuring the degree of vacuum inside the tank 3.

With the above configuration, the valve 22
, with valve 75 and valve 76 closed.
By opening 2 and operating the vacuum pump 5, the gas in the tank 3 is exhausted by the vacuum pump 5,
The inside of the tank 3 can be brought into a reduced pressure state close to vacuum of about 10<-4 >Torr. Further, by adjusting the opening degree of the valve 75, the amount of air flowing into the tank 3 through the valve 75 can be adjusted, and the pressure inside the tank 3 can be set from a reduced pressure state close to vacuum to atmospheric pressure.

The operation of the charge amount measuring device of this embodiment constructed as described above will be described below. After opening the valve 72 and closing the valves 22, 75, and 76, a predetermined amount of the liquid sample 6 is injected into the charge detection tube 11 from the liquid injection part 11c.

Next, by operating the vacuum pump 5, the pipes 71, valves 72, pipes 73, gas cooler 4,
The gas inside the tank 3 is exhausted via the piping 74, and the gas inside the tank 3 is exhausted.
Reduce the pressure inside to about 10-4 Torr. In this state, the valve 72 is closed and the valve 75 is gradually opened while adjusting the opening degree to allow outside air to flow into the tank 3 and adjust the pressure inside the tank 3 to a predetermined pressure value. When the pressure reaches a predetermined value, the valve 75 is closed, and then the switch 24 is turned on to open the valve 22.

Since the liquid storage portion 11d of the charge detection tube 11 is at atmospheric pressure, when the valve 22 is opened, the sample 6 is sucked into the tank 3 via the pipe 21, valve 22, and pipe 23. It will be done. At this time, the charge detection tube 11
is charged with a flowing charge amount that is equal to and has an opposite polarity to the charge amount generated on the sample 6 due to contact and separation between the sample 6 and the charge detection tube 11.

The charge thus charged on the charge detection tube 11 flows to the charge amount detector 41 via the charge amount detection terminal 11b and the lead wire 42, and the amount of charge is measured by the charge amount detector 41. be done. Therefore, the flow charge amount of the liquid sample 6 can be measured. In this way, the sample 6 is not circulated and used for one measurement as in the conventional method, so there is no problem of sample characteristics changing with each measurement, and measurement data with good reproducibility can be obtained. .

Using a commercially available special grade reagent as sample 6, the results were measured by the above-mentioned measuring method, and the results are shown in FIGS. 3 to 7 and Table 1.
It is shown in Table 2. In addition, the charge detection tube 1 used for these measurements
No. 1 was used having the size described above.

In FIG. 3, a 150 mesh net is used as the net 12, and the amount of sample 6 injected into the charge detection tube 11 is 3 ml.
The results of investigating the effect of replacing sample 6 on charging characteristics and reproducibility of measurement when the pressure value in tank 3 was set to 10-4 Torr and sample 6 was changed in the order of hexane, acetone, and hexane are shown. It is a graph. The solid line in FIG. 3 is the result of the first test using hexane, and the broken line is the result of the second test. As shown in FIG. 3, it can be seen that the flow charge amount, whose unit is nC, approaches a constant value while following different paths as the number of measurements increases. Also,
There is almost no difference in the respective convergence values, and the reproducibility of the measurements is also seen.

FIG. 4 is a graph showing the relationship between the suction differential pressure and the flow charge amount when a 200 mesh mesh is used as the mesh 12 and 3 ml of hexane is injected as the sample 6. Figure 4
As shown in Figure 2, the flow charge amount increases as the suction differential pressure increases.

FIG. 5 is a graph showing the relationship between the number of meshes of the net 12 and the flow charge amount when 3 ml of hexane is injected as the sample 6 and the pressure value in the tank 3 is set to 10 -4 Torr. As shown in FIG. 5, the amount of flow charge increases as the number of meshes of the net 12 increases.

FIG. 6 shows sample 6 when a 200 mesh net is used as the net 12, hexane is injected as the sample 6, and the pressure value in the tank 3 is set to 10-4 Torr.
3 is a graph showing the relationship between the amount of liquid and the amount of flow charge. Figure 6
As shown in , the flow charge amount increases as the sample amount increases.

Table 1 shows that a 150 mesh net is used as the net 12, 3 ml of sample 6 is injected, and the pressure value in tank 3 is set to 1.
The graph shows the results of examining the flow charging characteristics of various samples when set at 0-4 Torr. As shown in Table 1, the conductivity of the sample exhibits a characteristic in which the flow charge peaks in the range of 10-7 to 10-6 S/m.

[0025]

[Table 1]

Next, using a 32 mesh net as the net 12, 0.5 ml of the sample 6 is injected to create a state in which a sample film is formed between the meshes of the net 12, and the formed sample film and the net 1
The charging state when the sample 6 attached to the sample 2 was peeled off from the net by suction was investigated. FIG. 7 is a graph showing the relationship between suction differential pressure and peeling charge amount when acetone is used as sample 6. As shown in FIG. 7, the amount of peeling charge increases as the suction differential pressure increases.

Table 2 shows the pressure value inside the tank 3 at 10-4T.
These are the results of examining the peel-off charging characteristics of various samples 6 when set to orr. As shown in Table 2, the electrical conductivity of Sample 6 exhibits a characteristic in which the peeling charge amount peaks in the range of 10-7 to 10-6 S/m.

[0028]

[Table 2]

The measurement results shown in FIGS. 3 to 6 and Table 1 qualitatively agree well with past measurement reports, and it can be seen that the liquid charge amount measuring device of this example is practical. Furthermore, the net 12 may be made of a material other than SUS304, so that changes in the amount of charge on the sample 6 depending on the material of the net 12 can be measured. Furthermore, a plurality of nets 12 may be stacked, thereby making it possible to measure changes in the amount of charge on the sample 6 depending on the number of nets 12 stacked.

FIG. 8 shows a longitudinal cross-sectional view of a second embodiment of the charge amount measuring section 1 used when measuring the amount of charge using a net 12 made of an insulating material such as nylon, Tetron, polyethylene, etc. . Note that the same components as in FIG. 2 are given the same reference numerals, and their explanations will be omitted. The second charge detection tube 101 is screwed into the insulating tube 13 as described above, and the bottom surface 1 of the recess 101a formed in the second charge detection tube 101 is screwed into the insulation tube 13.
A net 12 made of an insulating material is placed on 01b. Furthermore, the recess 101 is located on the outer peripheral surface of the second charge detection tube 101a.
A screw 101c is formed in the portion where a is formed.

The first charge detection tube 100 has a liquid injection part 11 having the same shape and size as the charge detection tube 11 described above.
c, a liquid storage part 11d, a liquid discharge part 11e, and a flange 100a projecting in the circumferential direction is formed on the entire outer circumferential surface of the first charge detection tube 100 corresponding to the liquid discharge part 11e. The diameter of the flange 100a is smaller than the inner diameter of the recess 101a, and the flange 100a can be inserted into the recess 101a, so that the end surface 100b of the flange 100a and the mesh 12 come into contact.

First charge detection tube 1 installed as described above
00, the fastening metal fitting 102 has a recess 102c formed in the bottom surface 102a with a hole 102b having a diameter slightly larger than the outer diameter of the first charge detection tube 100 and smaller than the outer diameter of the flange 100a. A screw 102d inserted through the first charge detection tube 100 and formed on the inner peripheral surface of the recess 102c and the second charge detection tube 101
The screw 101c is engaged with the screw 101c. Therefore, the fastener 102
By screwing in, the bottom surface 102a of the fastening fitting 102 and the flange 100a of the first charge detection tube 100 come into contact, and by further screwing, the first and second
charge detection tubes 100 and 101 can be fastened together.

With this configuration, the amount of charge generated in the mesh 12 made of an insulating material can be detected by the charge amount detection terminal 11b and the lead provided on the first charge detection tube 100, as in the case of a mesh made of metal. The charge amount can be measured by the charge amount detector 41 via the line 42 .

In each of the above-mentioned embodiments, as shown in FIG.
Although the charge detection tube 11 etc. having the structure as described above was used,
However, the inner diameter, length, and structure of the charge detection tube may be appropriately designed to increase the detection sensitivity of the amount of flow charge and the amount of peeling charge that occur when the sample 6 is sucked into the tank 3. Bye.

As explained above, according to the charge amount measuring device of each of the above embodiments, the shape of the filter material, container, etc. is not complicated, and the sample liquid is not used in circulation. It is possible to quantitatively measure both the flow charge amount and peeling charge amount of the liquid without changing the characteristics of the liquid, and the measurement data does not change significantly.It is highly accurate and has excellent reproducibility under the same measurement conditions. Measurements can be taken.

[0036]

As described in detail above, according to the present invention, after a liquid sample is brought into contact with a charged detecting body and removed from the charged detecting body, the amount of charge on the charged detecting body is measured by the charge amount measuring means. Since the filter material and the shape of the container are not complicated, and the sample liquid is not recycled, the characteristics of the sample liquid will not change and the measurement data will change significantly. A liquid charge measurement method that allows you to measure both the flowing charge amount and peeling charge amount of a liquid in a filter with easy operation without having to use a filter, and is highly accurate and has excellent reproducibility of measurement conditions compared to conventional methods. equipment can be provided.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a liquid charge amount measuring device of the present invention.

2 is a longitudinal cross-sectional view of the charge amount detection section shown in FIG. 1. FIG.

FIG. 3 is a graph showing the relationship between the number of measurements and the flow charge amount.

FIG. 4 is a graph showing the relationship between suction differential pressure and flow charge amount.

FIG. 5 is a graph showing the relationship between the number of meshes of the net and the flow charge amount.

FIG. 6 is a graph showing the relationship between sample amount and flow charge amount.

FIG. 7 is a graph showing the relationship between suction differential pressure and peeling charge amount.

8 is a longitudinal sectional view showing a second embodiment of the charge detection section shown in FIG. 1. FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1... Charge amount detection part, 2... Storage container, 3... Tank, 5... Vacuum pump, 6... Liquid sample, 11... Charge detection tube, 12...
Net, 13... Insulating tube, 41... Charge amount detection meter.

Claims (1)

[Claims] 1. A charged detector that is charged by contacting and separating a liquid sample; sample removing means that brings the sample into contact with the charged detector and removes the sample from the charged detector;
A charge amount measuring means for measuring the charge amount of the charge detection body;
An apparatus for measuring the amount of charge of a liquid, comprising: a shield that blocks noise from the outside to the charge detection body.