Working principle of high pressure homogenizer and its advantages and disadvantages

The high-pressure homogenizer uses a high-pressure reciprocating pump as the power transmission and material conveying mechanism to transport the material to the working valve (the first-stage homogenizing valve and the secondary-stage emulsification valve). The material to be treated, during the process of passing through the working valve, produces strong shear, impact and cavitation under high pressure, so that the liquid substance or the liquid-supported solid particles are ultra-fine.

        When the material has not passed the working valve, the valve core and the valve seat of the primary homogenizing valve and the secondary emulsification valve are closely attached under the action of the forces F1 and F2. When the material passes through the working valve, both the spool and the valve seat are forced to squeeze a slit by the material, and pressures P1 and P2 are generated to balance the forces F1 and F2, respectively. When the material passes through the first-stage homogenizing valve, the pressure drops from P1 to P2, and as the pressure energy is suddenly released, a similar explosion effect occurs in a narrow area composed of the valve core, the valve seat and the impact ring. The strong cavitation, accompanied by the shearing action of the material through the slit between the valve core and the valve seat and the high-speed impact of the impact with the impact ring, so strongly combined, so that the particles are ultra-fine . In general, the pressure of P2 (ie, the emulsification pressure) is adjusted very low, and the role of the secondary emulsification valve is mainly to make the particles that have been refined more evenly distributed.

Classification of high pressure homogenizers:

According to the structure type, it is divided into a vertical integral homogenizer and a horizontal combined homogenizer. The former is generally suitable for small and medium-sized equipment (power below 45kw); the latter is suitable for large equipment (power is above 45kw). At present, most domestic manufacturers produce vertical integral homogenizers. This type of compact structure has a beautiful appearance and a small footprint. But for large devices, stability is a major issue. The so-called horizontal combined homogenizer refers to the relatively independent blocks of the motor, the reduction box, the crankcase, the lubrication station, etc., and is distributed on the same horizontal plane, and is integrated by a belt (wheel), a coupling, a tubing, and the like. The machine has a low center of gravity, stable operation and convenient maintenance.

According to the number of reciprocations of the plunger per minute, it is divided into a common type homogenizer and a low speed type homogenizer.

In the United States, Gazin Company classifies the number of reciprocating times per minute of the plunger to 150 or less for low speed type, and the number of reciprocating times of 150 times or more is called normal type. The speed of the homogenizer crankshaft (that is, the reciprocating frequency of the plunger is determined year by year) is one of the key factors determining the performance of the whole machine. In the case of the same material, processing accuracy, structure, etc., the lower the rotation speed within a certain range, the wear degree of each friction pair (such as shaft and tile, plunger and seal, etc.) per unit time, and the force in the pump body. The damage degree of parts (such as valve core, valve seat, etc.) is greatly reduced in the same time, and the stability of equipment operation is also greatly improved.

According to the control mode, it can be divided into manual control type, manual adjustment hydraulic control type and fully automatic control type. Currently, manual control is dominant in the market. If the entire production line is automatically controlled, a fully automatic control homogenizer can be used. For the automatic control homogenizer, please refer to "Homogeneous Machine, Spray Pump Automatic Control Technology"

According to the use situation, it can be divided into production homogenizer and experimental homogenizer. JHG series experimental homogenizer has the following characteristics: 1) Compared with the experimental machine with vertical horizontal (upper and lower) movement of the plunger, the plunger can spray cooling water to extend the plunger seal. Life 2) After the material leaks, it will not enter the fuel tank. 3) The overall shape of the cube is beautiful and easy to operate, and it can be easily transported by adding wheels.

According to the position of the homogenizer on the production line, it can be divided into an upstream homogenizer and a downstream homogenizer. The homogenizer used before sterilization is called the upstream homogenizer, and the homogenizer used after sterilization is called the downstream homogenizer. Usually the former uses a general homogenizer, while the latter uses a sterile homogenizer. The so-called aseptic homogenizer is to isolate the leakage point of the dynamic seal at the plunger of the homogenizer and the leak point of the static seal at the inlet and outlet with the atmosphere by steam (or superheated water). The bacteria equipment is used after sterilization.

Compared with centrifugal dispersing emulsification equipment (such as colloid mill, high shear mixing emulsifier, etc.), the advantages of high pressure homogenizer are:

1. The refinement effect is more intense. This is because the valve spool and the valve seat of the working valve are in close contact with each other in the initial position, but only a slit is forcibly extruded by the liquid during operation; and the high speed is satisfied between the rotating stators of the centrifugal emulsification device. Rotating and not generating too much heat, there must be a large gap (relative to the homogenizing valve); at the same time, since the transmission mechanism of the homogenizer is a volumetric reciprocating pump, in theory, the homogenizing pressure can be unlimited The ground is raised, and the higher the pressure, the better the refinement effect.

2. The refinement of the homogenizer mainly utilizes the interaction between the materials, so the calorific value of the material is small, so that the performance of the material can be kept basically unchanged.

3. The homogenizing machine can quantitatively transport the material because it relies on the reciprocating pump to feed.

Main disadvantages:

1. The homogenizer consumes a lot of energy, the homogenizer has more damage, and the workload is large, especially under high pressure.

2. The homogenizer is not suitable for high viscosity conditions.

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