JPS58104382A - Control method and device for delivery amount by pump - Google Patents

Abstract

PURPOSE:To obtain the stable delivery of liquid by providing a pressure control system for a liquid delivery pump in addition to a flow control system to minimize the variation of the delivery amount of liquid. CONSTITUTION:A painting liquid 12 in a delivery tank 11 is delivered continuously to a painting machine through a delivery pipe 13 by a delivery pump 14. The painting liquid is delivered as being controlled in its pressure by a pressure control system provided with a pressure detector 15 and a pressure regulating gauge 16 linked with the pump 14, and at the same time, controlled in its flow by a flow control system provided with a flow detector 17, a flow regulating gauge 18, and a flow control valve 19 for determining the amount of painting. It is delivered to the painting machine stably, and continuously applied on a web.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for controlling the flow rate of a liquid sent by a pump, and in particular to a flow rate control method and apparatus suitable for sending a coating liquid to a coating device that requires strict flow control. It is related to the device.

Generally, photographic materials such as photographic light-sensitive materials are manufactured by coating one or more layers of photographic coating liquid on a running web. Conventionally, there are various methods for applying photographic coating liquids, and the means for determining the amount of coating liquid to be applied to the web differs depending on these coating methods. - When applying a coating liquid to a web, it is usually sent to a coating machine through a liquid delivery pipe prepared at another location, but among the various coating methods, for example, air knife method, blade coating method, etc. After an appropriate amount of coating liquid is supplied to the nib surface, the desired coating amount is obtained by blowing or scraping off the coating liquid from the web surface with an air jet or blade. Therefore, in these coating methods, the coating liquid can be supplied so that there is no extreme addition or deficiency, so strict flow rate control is not required for feeding the liquid to the coating machine. Hereinafter, a coating method in which a desired coating amount is obtained by supplying a coating liquid onto these -H nibs and then scraping off the coating liquid will be referred to as a post-metering coating method.

On the other hand, in the case of a bead coating method or a curtain coating method, which has recently been used for high-speed, multilayer coating, the amount of coating is determined in advance by the flow rate of the liquid sent to the coating machine prior to coating.

Of course, the amount of coating is determined by the relationship between the coating speed and the flow rate, but once the coating speed is determined, the amount of coating is controlled by controlling the flow rate. Hereinafter, a coating method in which the amount of coating is determined in advance prior to coating will be referred to as a pre-metered coating method.

Conventionally, the flow rate control of these coating liquids has been performed using a control system shown in FIG. 1 or 2. Figure 1 shows a method for controlling the flow rate of liquid by using the natural gravity pressure caused by the head difference between the liquid sending tank and the coating machine (not shown). The flow rate of the liquid sent through the pipe 3 is controlled by a flow control system consisting of a flow rate detector 4, a flow rate (indication) controller 5, and a flow rate control valve 6. FIG. 2 shows a conventional method for controlling the flow rate of liquid by using a pump. The coating liquid 2 in the liquid sending tank 1 is fed by a pump 7 whose rotation can be controlled, and a flow rate detector 4 is connected to the pump. A flow rate control system consisting of a flow rate (instruction) controller 5 and a flow rate (instruction) controller 5 controls the flow rate of the liquid.

Liquid feeding using natural gravity pressure due to head difference as shown in Figure 1 provides stable liquid feeding pressure and enables highly accurate flow rate control, but as the coating speed is increased and the flow rate is increased, When the viscosity of the liquid is high, it is necessary to widen the head, which has the drawback of requiring a huge amount of space in terms of equipment. On the other hand, as shown in Figure 2, the method of sending liquid using a pump uses the pressure of the pump to send liquid, so it does not require a huge amount of equipment space, and the liquid sending pressure can be freely varied. Therefore, it is easy to cope with wide fluctuations in coating speed and fluctuations in coating viscosity. However, compared to liquid feeding using natural gravity, liquid feeding using a pump has the drawback that the feeding pressure of the coating liquid fluctuates, and conventional flow rate control methods cannot achieve stable and highly accurate flow rate control. Although such a conventional flow rate control method using a pump does not have a large effect on the post-metering type coating method, in the case of the pre-metering type coating method where the amount of coating is determined in advance by the flow rate, it is less effective than the conventional method. Strict flow rate control, preferably based on natural gravity pressure, is required, comparable to liquid delivery.

An object of the present invention is to provide a flow rate control method that can control the flow rate of liquid sent by a pump more stably and with higher precision than conventional methods.

Another object of the present invention is to provide a method for controlling the flow rate of a coating liquid, which is suitable for a type of coating system in which the coating amount is controlled only by flow rate control (namely, a pre-metering type).

Another object of the present invention is to provide a method for controlling the flow rate of a photographic coating liquid, which is suitable for a type of coating system in which the amount of coating is controlled only by controlling the flow rate.

Another object of the present invention is to provide a flow control device used to achieve the above object.

The object of the present invention is achieved by using a flow rate control method and apparatus that combine a pump pressure control system and a flow rate control system.

Regarding the present invention, a method for controlling the flow rate of liquid feeding by a pump, which is one embodiment of the present invention shown in FIG. 3, will be described below. The coating liquid 12 in the liquid feeding tank 11 is continuously fed to a coating machine (not shown) through a liquid feeding pipe 13 by a liquid feeding pump 14 whose rotation can be controlled. The coating liquid is fed while controlling the liquid pressure by a pressure control system equipped with a pressure detector 15 and a pressure (indication) controller 16 that are linked to the pump 14, and a flow rate detector 17 and a flow rate (indication) controller 18. and flow control valve '1
The amount of coating is determined by controlling the flow rate using a flow rate control system equipped with 9, and the liquid is sent to a coating machine and continuously coated on the web.

According to the present invention, in addition to the conventional flow rate control system, a pressure control system for the liquid pump is provided, so fluctuations in the amount of liquid fed are reduced compared to the conventional method, and liquid feeding is as stable as liquid feeding using natural gravity pressure. becomes possible. Therefore, even if the flow rate control method of the present invention is applied to a pre-metered coating method such as a bead coating method or a curtain coating method, the amount of coating can always be stably and accurately obtained.

The flow rate control method of the present invention is particularly effective in the production of photographic materials that require highly accurate thin layer formation by pre-metered coating methods. Of course, it goes without saying that this method can also be used as a flow rate control method for post-metering coating methods.

A photographic material consists of a silver halide emulsion layer containing or not containing a coupler, an anti-ration layer, a subbing layer, an interlayer 1. A protective layer, a back coating layer, a photosensitive polarized diazo compound-containing layer, a photopolymerizable polymer-containing layer, a photoconductive substance-containing layer,
It includes materials broadly described as photographic materials having photographic layers such as an image-receiving layer for silver salt diffusion transfer method and various constituent layers forming printing plate materials used in photolithography17, and photographic coating fluids refer to these materials. Refers to the coating liquid that forms the photographic layer.

Example 1 An aqueous gelatin solution having a viscosity of 10 centipoise was prepared and used as a coating liquid. The flow rate of the coating liquid was set at 1.500 m/min, and the fluctuation range of the flow rate was measured using the following three flow rate control methods, and the rate of variation with respect to the set flow rate was determined. An electromagnetic flowmeter was used to measure the flow rate. Maximum discharge amount of liquid by pump is 340
A gear pump with a low pulsation flow of 0 d/min was used.

(A) Flow rate control method using natural gravity pressure liquid feeding (U
Conventional flow rate control method using pump liquid feeding (C) The results of the flow rate control method using pump liquid feeding according to the present invention are shown in the table below.

From the above results, the flow rate control method (0) using a pump according to the present invention has a greatly improved fluctuation rate compared to the conventional method (B), and is a good method for controlling the flow rate using a pump using natural gravity pressure. It is recognized that results are obtained.

Example 2 A gelatin-silver halide photographic emulsion with a viscosity of 20 centipoise was used as a coating liquid, and a coating liquid flow rate of 300 M was applied to a slide hopper type bead coater using control methods B and C of Example 1.
/min, and the wet coverage of the coating liquid is 50v/-.
When applying the coating to one side of double-sided polyethylene coated paper, it was found that the conventional control method B had a variation in coating amount of 29/lri, but the variation in the coating amount of the control method C of the present invention was 0.
5g/rr? It was below. The amount of coating was confirmed by measuring the amount of silver coated.

[Brief explanation of the drawing]

1 and 2 are schematic explanatory diagrams showing a conventional flow rate control method, and FIG. 3 is a schematic explanatory diagram showing one aspect of the flow rate control method of the present invention. ■ and 11 are liquid sending tanks 2 and 12 are coating liquids 3 and 13 are liquid feeding pipes 4 and 17 are flow rate detectors 5 and 18 are flow rate (indication) regulators 6 and 19 are flow rate control valves 7 and 14 are rotation control Possible liquid feeding pump 15 is a pressure detector 16 is a pressure (indication) controller Figure 1 Figure 3 Figure 2 Procedural amendment (Mutsu) 1981 and month J/day Director General of the Japan Patent Office Kazuo Wakasugi ~ 2. Invention Name of the method and device for controlling the flow rate of liquid delivered by a pump 3, and its relationship to the case of the person making the amendment Patent applicant address 4-2 Marunouchi Pressure-chome, Chiyoda-ku, Tokyo Name (598) ';-(Ten)Zo Stock Company 4, Agent address: 5, Mitsubishi Paper Mills Co., Ltd., 3-4-2 Marunouchi, Chiyoda-ku, Tokyo 100, Japan Date of amendment order: Showa, Month, Day 8, Contents of amendment (1) Page 6, 20 of the specification Corrected line ``Flow rate control surface'' to ``Current current control system.'' (8) Corrected “described” to “recognized” on page 7, line 20 of the same page.

Claims (5)

[Claims] (1) In the method of controlling the flow rate of liquid feeding by a pump,
A flow rate control method characterized by combining a pump pressure control system and a flow rate control system. (2) The flow rate control method according to claim 1, wherein the liquid feeding by the pump is the feeding of the coating liquid to the coating device. (3) The flow rate control method according to claim 2, wherein the coating device is of a type in which the amount of the coating liquid applied onto the material to be coated is controlled only by controlling the flow rate of the coating liquid being delivered. (4) The flow rate control method according to claim 2 or 3, wherein the coating liquid is a coating liquid for forming a constituent layer of a photographic material. (5) Liquid feeding pressure control means equipped with a rotationally controllable liquid feeding pump, a pressure detector, and a pressure regulator; and a liquid feeding flow rate control means equipped with a flow rate detector, a flow rate regulator, and a flow rate control valve. Flow control device with.