JPS62276436A - Apparatus for detecting and controlling concentration of alcohol in dampening water device of offset press - Google Patents

Abstract

PURPOSE:To obtain good response, by supporting a submerged bottle so as to fully submerge the same in dampening water and detecting the wt. of the submerged bottle in water to control an alcohol injection value. CONSTITUTION:Because the wt. and displaced volume of a submerged bottle 3 are constant, for example, if the concn. of alcohol in dampening water 1 lowers, the specific gravity of dampening water becomes high and the buoyancy acting on the submerged bottle 3 becomes large and the shape of the cross rod supporting the submerged bottle 3 changes. Extension and contraction are also generated in the strain gauge 5 adhered to the cross rod 4 and the change in an electric resistance value is generated to be transmitted to a control panel 7 through a lead wire 6. The control panel 7 applies conversion processing to the signal from the strain gauge 5 display the same as the concn. of alcohol in the dampening water. This concn. of alcohol is compared with a set value to control an alcohol injection valve 9.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Industrial Application Field 1 This invention detects the alcohol concentration in the dampening water in the dampening water device of an offset printing machine, and detects the alcohol concentration at a desired value. Relates to a device for controlling the injection of alcohol so that

[Prior Art 1 In an offset printing press, it is necessary to apply dampening water to the print on the plate cylinder. A dampening system is provided. As shown in Figure 3, the part of the dampening water device that adjusts the properties of the dampening water includes a main water tank 41 equipped with a dampening water circulator, etc., and a part for adjusting the temperature of the dampening water. Cold fi 11 machine 42 and dampening water p
p11 control 43 that adjusts the H degree and alcohol concentration control 4 that adjusts the alcohol concentration of dampening water
4 and a water tray 45 for supplying dampening water to the plate cylinder, which are connected by a circulation pipe as shown.

The reason why an appropriate amount of isopropyl alcohol is added to the dampening solution in the alcohol concentration control 44 is to lower the surface tension of the dampening solution to improve so-called "water wetting" and to obtain good printing results. As shown in Figure 4, the surface tension of the dampening solution changes depending on the volume ratio of isopropyl alcohol.
As shown in Figure 5, alcohol concentration can be determined by measuring the temperature and specific gravity.If the temperature is constant, the alcohol concentration can be determined by measuring the specific gravity of the dampening water.
The surface tension of the dampening solution can be adjusted by adjusting the strength.

Therefore, in the dampening water device of an offset printing press, the alcohol concentration has been controlled and adjusted by utilizing changes in the specific gravity of the dampening water. As a conventional device for controlling alcohol concentration, one shown in FIG. 6 is used. This is alcohol concentration control 4.4
A specific gravity bottle 7 floating in a dampening water sampling container 71
A valve body 73 is integrally connected to 2, and the movement of the specific gravity bottle 72, which moves up and down in response to changes in the specific gravity of dampening water, directly causes the movement of the valve body 73, opening and closing the valve, and opening and closing the alcohol reservoir 74.
It is used to inject or stop the alcohol inside. At this time, since the vertical position of the specific gravity bottle 72 needs to be determined only by the specific gravity of the dampening water, the height of the water surface must be kept constant. Therefore, an overflow pipe 75 is provided. A mixing adjustment knob 76 is connected to the overflow pipe 75.
5 can be set, the height of the water surface can be set, and the alcohol concentration can be made to a desired value. Also, if the water surface ripples, the specific gravity bottle 72 will move, opening and closing the space between the valve body 73 and the valve seat 77, which will cause the valve to malfunction. , is injected into a side chamber 78 communicating with the bottom of the container 71.

[Problem to be Solved by the Invention 1] As described above, in the conventional alcohol concentration control tlO device in the dampening water device of an offset printing machine, the pycnometer and the alcohol injection valve are directly connected, and the pycnometer is directly connected to the alcohol injection valve. Since the movement directly opens and closes the alcohol injection valve, the height of the water surface of the dampening solution can be adjusted regardless of whether the amount of dampening water injected is large or small.
It must be constant and the water surface must not ripple.

Furthermore, for the reasons mentioned above, the sampling container 71
It is not possible to increase the circulation amount of dampening water. Therefore, even if the alcohol concentration of water [n45 or the dampening water in the main tank 41 decreases due to evaporation of alcohol, the sampling container tends to be delayed in following the dampening water. Therefore, in actual operation, for example, even if an alcohol concentration of 5% is sufficient, artificial adjustments are made, such as setting the alcohol concentration in the sampling container to 15%, and the amount of alcohol consumed is higher than necessary. The problem is that there are many

Furthermore, alcohol concentration changes moment by moment due to evaporation, etc., but there is no way to continuously detect this, so i! There is also a lack of means to control it.

[Means for Solving the Problem 1] In order to solve this problem, this invention provides an alcohol concentration detection control I in a dampening water device of an offset printing press that detects and controls the alcohol concentration of the dampening water based on the specific gravity of the dampening water. The device includes a submersible bottle supported so as to be completely submerged in dampening water, a sensor for detecting the weight of the submersible bottle in water, a control panel for inputting and converting electrical signals from the sensor, and a control panel for inputting and converting electrical signals from the sensor. It is characterized by an alcohol injection valve whose opening and closing are controlled by the output of the panel.

[Function] The alcohol m content detection control device in the dampening water device of an offset printing press according to the present invention has the above-described configuration, and detects the underwater weight of the underwater bottle completely submerged in dampening water as an electric signal by a sensor, This controls the opening and closing of the alcohol injection valve, but since the submersible bottle is completely submerged in water, it is not affected by changes in the height of the water surface or ripples on the water surface, and the alcohol concentration can be accurately determined. shows. Therefore, there is no need for means for keeping the water surface level constant or for preventing waves from forming on the water surface, as in conventional devices. Furthermore, this underwater bottle can be directly
It can also be installed inside the main tank. In this way, the alcohol m degree can be detected continuously and without delay, allowing precise control and reducing alcohol consumption. Furthermore, since the opening and closing of the alcohol injection valve is controlled by electric signals from the sensor, the opening/closing point and opening/closing state of the valve can be freely set, and remote operability and good responsiveness can be achieved.

[Embodiments] The present invention will be described below with reference to illustrated embodiments. 1st
The figure is a schematic diagram of the first embodiment, and FIG. 2 is a schematic diagram of the second embodiment.

In FIG. 1, dampening water 1 is stored in a container 2, and the dampening water 1 is circulated and used in a water tray 45 (see FIG. 3) and the like. In this invention, the container 2 may be a sampling container 71,
The main water tank 41 may also be used. If the main water tank 41 is used, the sampling container 71 becomes unnecessary. The underwater bottle 3 is made of stainless steel, plastic, etc. and has a spherical shape or a cylindrical shape with hemispherical ends, and is supported by a horizontal bar 4 so as to be completely submerged in the dampening water 1. The weight of the underwater bottle is preferably about the same as the amount of water being discharged, but it may be heavier or lighter.

The horizontal bar 4 is made of an elastic material such as flat stainless steel, and both ends are fixed to the underwater bottle 3 and the container 2, respectively. A strain gauge 5 is attached to the horizontal bar 4.
A lead wire 6 is led from the control panel 7 to the control panel 7. Control panel 7
receives the electrical resistance signal from the strain gauge 5, converts it to the alcohol concentration of the dampening water 1, and displays it. It also controls the opening and closing of the alcohol injection valve 9 via the cable 8, and fills the alcohol 12 in the alcohol bottle 11. A desired amount of dampening water 1 is injected into the dampening water 1.

Since the weight and drainage volume of the underwater bottle 3 are constant, for example, if the alcohol concentration of the dampening water 1 decreases, the specific gravity of the dampening water increases, the buoyancy acting on the underwater bottle 3 increases, and the water bottle 3 The shape of the horizontal bar 4 that supports it changes, and the horizontal bar 4
The strain gauge 5 attached thereto also expands and contracts, causing a change in electrical resistance, which is transmitted to the control panel 7 through the lead wire 6.

The control panel 7 converts, processes, and displays this signal as the alcohol concentration of the dampening water. Also, this alcohol concentration is compared with the value set on the till control panel 7, and if it is lower than the set value, a valve opening command is output to the alcohol injection valve 9 via the cable 8, and alcohol 12 is dispensed from the alcohol bottle 11. Inject it into dampening water 1. As the alcohol concentration increases and the specific gravity of the dampening water 1 becomes smaller, the strain gauge 5 detects the change in the buoyancy of the underwater bottle 3, which is input to the control panel 7, and the control 017 sets the alcohol concentration of the dampening water 1. If it is determined that the value has been reached, the alcohol injection valve 9 is closed to stop the injection of alcohol.

The alcohol concentration of the dampening solution is controlled in the above manner. The alcohol concentration setting value can be set to any value on the control panel by the operator.

In the second embodiment shown in FIG. 2, a photoelectric switch is used to detect changes in the buoyancy acting on the underwater bottle 3. In FIG. 2, a light shielding plate 31 is connected to the underwater bottle 3, and is suspended by a spring 33. A light emitter 32.32a and a light receiver 34.34a are provided facing each other with a light shielding plate 31 in between. When the alcohol concentration in the dampening water 1 changes and the specific gravity of the dampening water changes, the underwater bottle 3 floats or sinks. Then, the light emitted from the light emitter 32.32a is either blocked by the light shielding plate 31 or not blocked, and is detected by the light receiver 34.34a and is controlled by the light shielding plate 31.
! 7 is input. The control panel 7 converts and processes this signal and outputs it to the alcohol injection valve 9.
open and close. In the second embodiment, for example, if a large number of projectors and light receivers are provided or if they are movable, the current status can be displayed and the set points can be adjusted and set remotely.

In addition to the embodiments described above, potentiometers, proximity switches,
It is also possible to use a method that utilizes a change in electric capacitance, a method that uses a change in phase difference, etc.

[Effects of the Invention] As explained above, in the alcohol concentration detection control device for an offset printing line warming water device according to the present invention,
In order to detect changes in the specific gravity of the dampening solution due to alcohol concentration, we used a submersible bottle that is completely submerged in water, which prevents unwanted changes in the water surface height that were required with conventional specific gravity bottles, and also prevents the water surface from changing. Measures to prevent ripples are no longer required. Therefore, an overflow device, a side chamber compartment, a water injection control device, etc. of the sampling container are not required. The device according to the invention can also be installed in the main water tank, so that sampling containers are also not required. Particularly, when this VR device is installed in the main water tank, good responsiveness can be obtained because it detects and controls changes in the dampening water in immediate response to changes in alcohol concentration.

Furthermore, as mentioned above, it is less susceptible to disturbance conditions and therefore has good stability. Since it has good responsiveness and stability, there is no need to increase the alcohol m content according to the operator's expectations as in the past, and the amount of alcohol consumed can be reduced.

Furthermore, since the alcohol concentration is displayed and set on a control panel connected by a cable, the control panel can be remotely monitored and operated by a person who is away from the printing press in a favorable environment. Note that this control panel can be a comprehensive remote control panel that displays and controls temperature and pH as well as 1 degree alcohol.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of the first embodiment, Figure 2 is a schematic diagram 1 of the second embodiment, Figure 3 is a system diagram of a conventional dampening water device, and Figure 4 is a graph of surface tension versus alcohol concentration. , FIG. 5 is a graph of specific gravity relative to alcohol III, and FIG. 6 is a schematic diagram of a conventional alcohol m degree control device. In the figure, 1 is dampening water, 3 is an underwater bottle, 4 is a horizontal bar, and 5
is a strain gauge, 7 is a control tlJI, 9 is an alcohol injection valve, 11 is an alcohol bottle, 31 is a light shielding plate, 32
34 is a light projector, and 34 is a light receiver.

Claims (1)

[Claims] In an alcohol concentration detection control device in a dampening water device of an offset printing machine that detects and controls the alcohol concentration of the dampening water based on the specific gravity of the dampening water, an underwater bottle supported so as to be completely immersed in the dampening water; Offset printing characterized by comprising a sensor that detects the weight of a bottle in water, a control panel that inputs and converts electrical signals from the sensor, and an alcohol injection valve whose opening and closing are controlled by the output of the control panel. Alcohol concentration detection control device for the dampening water system of the machine.