JPS6279860A - Separation of solid matter from hardly separable liquid - Google Patents

Abstract

PURPOSE:To economically separate solid matter from liquid with high accuracy by using a double cant type decanter for solid-liquid sepn. in a food producing stage and specifying the degree of inclination for discharging settled solid particles. CONSTITUTION:The initial angle X of inclination of a sloped part 1a for discharging the settled solid particles is set larger than the angle Y of inclination of the terminal and the angle of inclination of the liquid surface part is set same as the angle Y or larger than said angle but smaller than the angle X in a method for separating the solid matter from the hardly separable liquid such as concd. coffee, fruit juice or soybean milk. The double cant type decanter is adopted for the solid-liquid sepn. in the food producing stage in the above- mentioned manner, by which the fine particles are separated and removed with good accuracy and the yield of the product is improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to the removal of solids and tar-like substances present in concentrated coffee, the removal of valve substances from fruit juice, the removal of okara from milk, etc. Concerning an improved method for performing.

[Conventional technology]

A screw-type continuous centrifugal sedimentation device called a super decanter, screw decanter, etc. has a mechanism for continuously discharging settled solid particles Y- to the outside. This type of device includes a conical or cylindrical-conical bowl that rotates at high speed, and a bowl that rotates with a small gap between the bowl and the bowl.
The bowl is equipped with a screw that discharges solid particles attached to the inner surface of the bowl to the outside of the bowl. However, in actual operation, the shape of this bowl becomes a problem.

The part that discharges the solid particles Y~ has a conical shape as described above, but in order to make the discharge effective, the angle of inclination of the conical part (slanted part) of the bowl must be made very small. . However, if the inclination angle is made small in this way, the length of the rotating body and the screw must be significantly increased. Therefore, in order to obtain the required performance, it is inevitable to increase the size of the device. This means that the installation space of the apparatus becomes large, which not only causes an increase in costs but also brings great inconvenience to the operation. In addition, the efficiency of operation also deteriorates.

In addition, if the inclination angle of the bowl cone is made smaller, the depth of the liquid in the bowl must be made shallower, so if the difference in specific gravity between the solid and liquid in the suspension to be treated is small, the separation of the solids will be insufficient. It will not be done.

In order to eliminate these drawbacks, one of the present inventors proposed a double cant type screw type continuous centrifugal sedimentation device disclosed in Japanese Patent Application Laid-open No. 54961/1983.

In this double-cant screw type continuous centrifugal sedimentation device, the initial inclination angle of the inclined part of the bowl for discharging settled solid particles is set larger than the final inclination angle, and the inclination angle at the liquid level is the same as the final inclination angle. or larger but smaller than the initial inclination angle, and the solids separated from the suspension are transported from the liquid surface direction F along a gentle slope to the north of the liquid surface. When separating solid and liquid using this device, the settled solid particles are subjected to centrifugal force under the liquid surface due to the difference in specific gravity between the liquid and the solid particles, and above the liquid surface, they are centrifuged in proportion to the specific gravity of the solid particles. subjected to the action of force.

Therefore, even if the angle of inclination of the slope section for solid particles below the liquid level is large, it is possible to transport the solid particles in the liquid. Since the force effect is relatively large, the angle of inclination was made small to facilitate transportation.

The above-mentioned double cant type device makes it possible to downsize the device while maintaining a high discharge capacity for settled solid particles.
Like activated sludge, it has a specific gravity of about 1.02 to 1.04, with a small difference in specific gravity from water, and is fine particles, and when dehydrated, it becomes pudding-like or paste-like and is extremely susceptible to plastic deformation. Satisfactory results can now be obtained even when a suspension of a substance that easily forms a cake is separated into solid and liquid.

In the production of instant coffee, it is known that the concentrated coffee at the outlet of the concentration equipment contains solid substances that have leaked from the separation equipment and solid substances and tar-like substances that have been generated in the concentration equipment. is approximately 10,000
Due to their centiboids and extremely high viscosity, there are no effective and economical separation methods, and these substances end up in the product.
When drinking, it remains at the bottom of the cup, giving an impression of quality, which has become a problem.

In addition, fruit juice contains sugar and persimmon acid as its solutes, has a liquid ratio greater than 1, and contains plant cellulose (pulp) as a solid, so it is difficult to centrifuge it, so it is difficult to use a screw press. filtration machines have been widely used as juice extraction machines. However, if the filtration accuracy is increased in an attempt to improve the clarity of fruit juice in a juice extractor, the filtration surface becomes clogged with pulp.

Therefore, in many factories, the extraction machine is operated with a large opening to prevent clogging, so 2 to 5% of the pulp leaks out during the extraction process, and in the later process the disc-shaped It is necessary to separate the pulp using a decanter (also called DeLaval type or Westfalia type).

However, due to the structure of such a decanter, the inside of the decanter is easily clogged, and the decanter is discharged as a pulpy concentrated slurry, resulting in a loss of fruit juice.

Furthermore, in the production of tofu, by separating okara from soy milk with high precision,
Although soybean milk containing no solids can be obtained, and the tofu obtained from this can be of excellent quality, there has been no known means for separating okara from soymilk with such high precision.

[Problem that the invention seeks to solve]

The present invention aims to provide a method for accurately and economically separating solids from liquids in the food manufacturing process as described above.

[Means for Solving Problems] Difficulties #The method of separating solids from liquid of the present invention is the removal of solids and tar-like substances from concentrated coffee, the removal of bulb-like substances from squeezed fruit juice, or When removing okara from σ milk, the initial inclination angle of the inclined part for settling solid particles Y and discharge of the bowl is set to be larger than the final inclination angle, and the inclination angle at the liquid level is set to be equal to the final inclination angle. The method is characterized in that the removal is carried out using a screw type centrifugal sedimentation machine set to be the same as or larger than the initial inclination angle but smaller than the initial inclination angle.

The screw type centrifugal sedimentation machine used to carry out the method of the present invention is
This is the so-called double cant type, and a typical example of its bowl and screw portion is shown in Figure 1. In FIG. 1, 1 indicates a bowl, 2 indicates a screw, and 3 indicates a liquid level. 1a is a sloped part for discharging settled solid particles, X shows the initial jυ1 inclination angle of this sloped part, and Y shows the final inclination angle. Z is the matching point of these two tiered inclined portions, and is located slightly below the liquid level 3. Angle X is IO° ~ 80°,
Preferably, the angle Y is between 2° and 15°. Further, the sloped portion may be multi-staged with three or more stages or a curved surface, and further, the sloped portion directly below the liquid surface is provided with a retention area to prevent the settled solid particles conveyed to the liquid surface from flowing back into the liquid. A section may be provided.

The separation of solids from liquids according to the present invention will be specifically explained below in the case of concentrated coffee, squeezed fruit juice, and soybean milk with reference to FIGS. 2 to 4.

Fig. 2 is a flow sheet showing an example of the instant coffee manufacturing process. The raw coffee is extracted with hot water in the extraction device 2I, and the coffee grounds are discharged from the bottom. Extract 7 & (coffee liquid) is subjected to separation and removal of accompanying solid matter in a solid-liquid separator 22, and then concentrated in a concentrator 23. Concentrated coffee from a concentrator is accompanied by solid matter produced during the concentration process, and has an extremely high viscosity of 10,000 centivoids.

This concentrated coffee is fed to a double cant type screw type centrifugal sedimentation machine (hereinafter referred to as a double cant type decanter) 24 having a bowl shape as shown in FIG. 1, and solids and tar-like substances are separated and removed. This separation operation in the double cant decanter removes fine particles down to 10 to 20 microns with almost 100% accuracy.

The instant coffee product 26 obtained by drying the concentrated coffee thus obtained in the drying device 25 had no residue on the bottom of the cup when drinking.

FIG. 3 of the valve 9 in items 21-' is a flow sheet showing an example of the fruit juice manufacturing process. The raw fruit is supplied to a crusher 31 by a belt conveyor and crushed, and the resulting crushed product is sent to a juicer 32, where the pulp is separated from the squeezed fruit juice. In the present invention, a double cant type decanter 32 as shown in FIG. 1 is used in place of the 32° screw press or the like conventionally used as the juice extracting machine. Double cant type decanter 32
The juice that comes out passes through a sterilizer 33 and is sent to packaging equipment 35. After going through sterilization equipment 36, it is made into pickles 37. Conventionally, the fruit juice from the juice extractor 32° contained 2 to 5% bulb quality, so it was necessary to install a bulb quality separator 34 after the sterilizer 33. Since the valve chamber contained in the juice exiting the juice extractor 32 can be operated to maintain the required concentration, for example, 0.3 to 0.6% by weight for cloudy apple juice, the valve quality separator 34 is omitted. be able to.

According to the present invention, the pulp exiting the juice extractor 32 is not recovered as a concentrated slurry, but as a cake with substantially all the juice squeezed out, so that there is no loss of juice and, therefore, a reduction in juice relative to the raw fruit. Yield is heading north.

-Kanooka C' Figure 4 is a flow sheet showing an example of the process for producing soymilk from soybeans. The raw soybeans are soaked in water for about one night in a soaker 41 to make them easier to grind, and then fed to a grinder 42 .

It is sufficiently and smoothly ground by a grinder 42 to obtain ground raw juice. This raw juice is heated in a heater 43 to extract fat and vegetable protein into the liquid. The soybean milk containing okara from the heater 43 is transferred to the double cant decanter shown in FIG.
44 to separate the soy milk from okara. The soymilk thus obtained was substantially free of solid matter, and the tofu produced therefrom was smooth and delicious.

Furthermore, since the soybean milk is sufficiently separated from the separated okara, it is possible to increase the yield of soymilk by 2 to 4% based on the raw soybeans.

〔Effect of the invention〕

As described above, according to the present invention, by employing a double cant decanter for solid-liquid separation in the food manufacturing process, it is possible to accurately separate and remove fine particles, which was previously impossible or difficult. can also improve product yield,
Furthermore, the process can be simplified, resulting in significant improvements in quality and reduction in manufacturing costs.

Although the present invention has been specifically explained with respect to the three food manufacturing processes mentioned above, it goes without saying that it can be advantageously applied to solid-liquid separation in various other food manufacturing processes. That's true.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram showing the bowl and screw portion of the double-cant screw type centrifugal sedimentation machine used in the implementation of the present invention, Figure 2 is a flow sheet showing an example of the instant coffee manufacturing process, and Figures 3 and 3 are illustrations of the bowl and screw portion of the double-cant screw type centrifugal sedimentation machine used in the implementation of the present invention. Flowsheet showing an example of the manufacturing process. FIG. 4 is a flowsheet showing an example of the process of manufacturing soybean milk from soybeans. 1... Bowl, 2... Screw, 3...
-Liquid level, 21--Extraction device, 22--Solid W, separation device, 23--Concentration device, 2
4-...Double cant type decanter-125...Drying device, 26...Product. 31... Crusher, 32... Juicing machine (double cant decanter), 32
°... Screw press, 33-... Sterilizer, 34... Pulp buying separator, 35... Packaging equipment, 36... Sterilization equipment, 4
1... soaker, 42-... grinder, i3...
・Heater, 44...Double cant type decanter - 0 Patent applicant: Mitsui Toatsu Chemical Co., Ltd., Ju Iron Works Co., Ltd.

Claims (1)

[Claims] Removal of solids and tarry substances from concentrated coffee,
When removing pulpy substances from squeezed fruit juice or removing okara from soy milk, the initial inclination angle of the inclined part of the bowl for discharging settled solid particles is set larger than the final inclination angle, and the liquid level is However, is the inclination angle the same as the terminal inclination angle?
Or a method for separating solids from a difficult-to-separate liquid, characterized in that the removal is carried out using a screw-type centrifugal sedimentation machine set to be larger than the initial inclination angle but smaller than the initial inclination angle.