JPS58100711A - Measuring method for quantity of liquid jetting from jet - Google Patents

Abstract

PURPOSE:To measure easily the quantity of a fluid jetted from a jet intermittently, by measuring pressure variation in a passage from a liquid source to the jet. CONSTITUTION:A glue 2 is sent out from a glue tank 1 by a compressed air 3. An interval from a pipe 4 in the tank 1 to a glue gun 5 is connected with hoses 9, 10 by using joints 6-8. The joints 6-8 are provided with pressure converter 14 and the output of the converter 14 is given to an electromagnetic oscillograph 16 and a memory scope 17 through an amplifier 15. The quantity of jetted fluid from the gun 5 is proportioned to the product of pressure drop and jetting time or the product of a rate of the pressure drop and the jetting time at each joint 6-8.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel method for measuring liquid t spouted from a spout.

BACKGROUND ART In recent years, when various products are continuously produced or processed, it is often the case that liquids such as liquid adhesives and coating materials are intermittently jetted out. For example, when boxes are manufactured continuously from corrugated paper, the corrugated paper used as the raw material is placed on a belt conveyor and transported, and the base pieces are glued to the box by the adhesive that is ejected at a certain position. are manufactured sequentially. Therefore, the adhesive is intermittently sprayed at a fixed position at fixed time intervals, and the corrugated paper backing piece sent to the lid is bonded to that position.

In this case, liquid adhesives with relatively high viscosity, such as glue or hot melt adhesives, are sent out from a container such as a tank at a constant pressure and temperature for each adhesive, and are usually delivered to the gun through a pipe with a length of about 1 to 5 meters. 0.1 every time from the nozzle etc.
An amount of ~1 g is sprayed and applied onto the target corrugated paper at a speed of about 0.05 to 0.6 seconds. This jetting operation is performed intermittently at a rate of about 20 to 25 times per minute.

However, during this process, for example, if the glue solidifies or foreign matter gets mixed in, the pipe or nozzle becomes clogged, resulting in a reduced amount of ejection, or the gushing or coating is not carried out, resulting in poor box manufacturing. Moreover, it is difficult to easily check the amount of intermittent ejection of a very small amount of liquid for a short period of time.

Therefore, it is an object of the present invention to provide a method that can easily measure the i of a liquid that is intermittently ejected in a very small amount for a very short period of time from an ejection nozzle through a pipe of a certain length. .

According to the research and experiments of the present inventors, the above object can be achieved by indirectly controlling the liquid t that is intermittently ejected from the ejection port by measuring the pressure change in the passage from the liquid source to the ejection port. It has been discovered that this can be achieved by a method characterized by a method of measuring

The present invention is applicable not only to the spouting and coating of viscous liquid adhesives such as glue and hot melt, but also to the spouting of low-viscosity liquids such as ordinary water. I will explain the drawings in detail.

In FIG. 1, for example, about 0.2 to 0.6 tg of glue 2 at room temperature is transferred from a glue tank 1 with a capacity of 24 by compressed air 3.
Delivered under 7ci pressure. Two hoses 9, 10 are connected using three joints 6, 7, and 8t for a length of about 3 m from the armhole 4 in the tank 1 to the glue gun 5.
Connect with. - For example, three joints each have a length of 1
03, the first hose 9 has a length of 170 cm, and the second hose 10 has a length of 90 cm.

The glue 2 sent to the glue gun 5 via each joint and hose is compressed air 1 controlled by a solenoid valve 11.
2 is intermittently spouted from the glue nozzle 13 under pressure,
applied.

A pressure transducer 14 is provided in one of the three joins 6, 7, and 8, and in this example is electrically connected to an amplifier 15, an electromagnetic oscillograph 16, and a memory scope 17. Reference numeral 18 indicates a timer for controlling the operation of the solenoid valve 11 over time. The pressure transducer 14 can be installed at any of the three joints 6, 7, and 8 mentioned above, but considering the size of the pressure change and the position, it is best to install it in the center. The joint located at 7 is most preferred. For example, if the joint 6 is located close to the tank, the pressure change will be small, and if it is installed at the joint 8 closest to the glue gun 5, that is, the center of the box making machine, it will tend to complicate the equipment in that area. This is somewhat inappropriate.

When installing this pressure transducer 14, if a very narrow aperture with a diameter of 211 m, for example, is inserted just before the measurement position, it is possible to enlarge it even at the position of the joint 6 where the pressure change is small, for example. In addition, as mentioned above, Otsushirograph 16
However, without providing the memory scope 17, it is also possible to provide a mechanism for immediately displaying the calculated liquid volume in numerical form, or a mechanism for issuing an alarm or stopping the device, as described below.

When the glue 2 sent from the glue tank 1 under pressure at room temperature is intermittently spouted from the nozzle 13 of the glue gun 5 under the control of the solenoid valve 11, the change in pressure from the glue tank to the nozzle can be expressed, for example, at the center joint. 7, a waveform as shown in FIG. 2 can be obtained.

FIG. 2(a) shows the case where Gulyagan 5 is in a normal state,
When the valve of glue gun 5 opens, the pressure is, for example, 0.6#/a
2.The initial pressure increases rapidly from the initial pressure, but quickly decreases and maintains a steady state at a pressure slightly lower than the initial pressure.When the valve closes, the pressure decreases rapidly and immediately increases before the valve opens. Return to pressure.

Here, the initial pressure is P, and the pressure at steady state and the initial pressure P,
Let P2 be the difference between the pressure drop and pressure drop, θ be the inclination angle or pressure drop rate at the time of pressure drop, θ be the time from when the valve opens until it closes, that is, the ejection time IT, and the amount of liquid ejected during this time be Q. The liquid amount Q is expressed by the formula QQCP2 XT (1) or QoeθXT (2). In other words, the amount of liquid ejected is proportional to the product of pressure drop and ejection time or the product of pressure drop rate and ejection time, respectively.If the proportionality constant is determined by the formula shown below, then pressure drop P2 and ejection time T, or pressure drop By measuring the rate θ and the ejection time Tt, the amount of ejected liquid can be easily calculated and measured without directly measuring it.

In Figure 2 (a), the wave line and the initial pressure when the valve opens, rises once, then falls below the initial pressure, passes through a steady state, and is below the initial pressure until the valve closes. The amount of ejected liquid can also be easily measured indirectly by calculating the area of the area surrounded by the edge, that is, the area marked with an "A" by integration.

Figure 2(b) shows a waveform showing the pressure change when the glue gun 5 is operated with the nozzle hole clogged.As is clear from the figure, the valve opens and the pressure immediately rises and then falls. However, the pressure returns to the initial pressure and does not show a pressure drop as shown in Figure 2 (,). Then, when the cell is closed, the pressure decreases rapidly, then immediately rises and returns to the initial pressure.

In other words, if the nozzle or spout of the glue gun is operating normally without clogging, a pressure drop will occur during the spouting time.
If the nozzle is clogged and not working properly, no pressure drop will occur. This difference is expressed as a waveform or the ejection amount as a number, and it is possible to know whether the ejection port is blocked or partially blocked. In that case, it is possible to immediately issue an alarm and take necessary actions such as stopping the machine.

The waveforms in Figures 2(a) and (b) were measured at the center when spraying glue using a gun with a diaphragm.
Or, it differs depending on the position to be determined and whether or not a restriction is placed at the measurement position. For example, when measuring near the tank, the pressure change is small, and even when squeezed, the pressure change is small. If the location is close to the cancer, the changes are more severe.

Next, FIG. 3 shows the waveform obtained when hot melt was ejected under normal conditions using a gun different from that shown in FIG. 2 and measured at the central position.

The initial pressure P is 20 kl 2 and the temperature is about 180'C.
It is.

In this case, even when the valve is opened, the pressure does not rise or fall rapidly, but drops immediately. In this case, as in the case of glue, the amount of hot melt ejected can be measured indirectly by measuring the pressure drop P2 or pressure drop rate θ or by calculating the area of the hatch. can.

When the nozzle is clogged, there is no pressure drop as with glue.
[The pressure change waveform is different when the gun is normally inflating the eyelids and when the nozzle is clogged, and there are differences in the pressure values when the valve is opened and closed and in a steady state.]

Considering the cause of this difference, when sending viscous liquid, a pressure difference is required between both ends of the pipe, and the initial pressure is PA,
If the pressure at the measurement position is PR, then the difference p, -pB
is expressed by Hagen-Boiseuille's formula as follows. Here, l is the distance to the measurement position, r is the radius of the tube, and η
is the viscosity ζQ is the volume of liquid flowing per unit time.

8ηBO PP--(3) AB-πr4 In other words, the pressure difference is directly proportional to the fQ of the liquid flowing per unit time, and therefore to the applied amount, so this can be measured to measure the liquid tt and determine whether the gun operation is normal or abnormal. You can know. The above formula (3) forms the basis of the above formula (1).

Next, the pressure change in the glue tube when one tube is closed is large because the valve is opened and closed rapidly, and this changes depending on the clogging state of the nozzle hole, the viscosity of the glue, compressed air, and other factors. When the nozzle is clogged, the opening and closing movement of the valve is slower than when it is normal, and the pressure change is
It gets colder.

In this way, it is possible to predict whether the glue gun is operating normally, clogged, or partially clogged based on the pressure difference in the steady state or when the valve is opened and closed.

Therefore, the ratio of the tank pressure (initial pressure) at the time of measurement to the pressure when it drops to a steady state, that is, the rate of pressure change, varies depending on various factors, and as mentioned above, it also depends on the measurement position and the presence or absence of a throttle. The time to operate the gun varies, for example, 0.6 seconds, 0.05 seconds, depending on the amount of ejection, the size of the nozzle, and the initial pressure.
Since it is also affected by the viscosity and temperature of the liquid, it is necessary to measure pressure changes while taking into account the effects of these factors.

Thus, according to the present invention, the amount of a particularly viscous liquid that is intermittently spouted in very small amounts from the spout for a very short period of time can be measured without directly measuring the amount, preferably in the middle between the liquid source and the spout. By measuring the pressure change in its passage at the location, it is easy to measure indirectly and easily detect whether the jet is normal or if the jet is in a blocked or semi-blocked state. Measures can be taken quickly.

Therefore, the present invention provides a truly effective method for measuring the amount of ejected liquid.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing an example of an apparatus for carrying out the method of the present invention, and Fig. 2 is a graph showing a waveform showing pressure changes during glue ejection by the method of the present invention, (1) is a normal state, (b)
) is the waveform when the nozzle is clogged, and FIG. 3 is a graph showing the waveform showing the pressure change when the hot melt adhesive is ejected using the method of the present invention. 1...Glue tank, 2...Glue, 5...Glue gaff, 6,7.8...Join), 9*10...
Joint, 14...pressure transducer. Dejojin representative Inomata Kiyoma 2nd figure (a) (b) Horse 3rd figure

Claims (1)

[Claims] The amount of liquid ejected from the ejection port is measured by measuring the t't of the liquid ejected intermittently from the ejection port, and the pressure change in the passage from the liquid source to the ejection port. Measuring method.