CS236046B1 - Device for dosing, preparation and injection of compositions from liquid polymers - Google Patents

Abstract

The purpose of the invention is to provide a device for dosing, preparation and injection liquid polymer compositions for Wide viscosity range from 0.01 Pas to 10® Pas. The purpose is achieved by being on the sliding three separate pumping stations are placed on the counter (l) dispensing systems based on viscosities into gear pumps (4) or piston pumps (5) optionally a three-spindle supercharged pumps (3) in the required combination. Similarly, a homogenizer for less viscous Ingredients up to 10 ^ Pas Is used cylindrical and for viscosity components to viscosities 10® Conical waist homogenizer, both of them stators and rotors tempered and in place a homogeneous reactive composition Pressure sensors (8) are located injection cycle and temperature sensors (9) control homogenization process.

Description

The invention relates to a device for dispensing, preparing and injecting two or more filled or unfilled separately relatively stable components into homogenizers, in which the input components are homogenized with each other on a reactive composition which is injected by pressure exerted by dispensing systems into a mold cavity. or a porous product.

The devices currently used use two basic principles, or combine the advantages of both. One method uses metering pumps to meter and deliver the components typically to mechanical homogenizers. The second method uses metering pumps to measure and achieve high inlet pressures into a homogenization, suitably shaped cavity, where vigorous pressure drop causes intensive mixing and homogenization. these devices are often supplemented with a static mixer.

If a homogeneous reactive composition is to be injected into molds, both basic methods are complemented; an injection device, usually a piston, which, under pressure, moves the composition from the piston space into the mold cavity. These devices are said in a number of ways, often very complicated, both in mechanical and electrical control, and most of them have a significant disadvantage in the constant injection volume or in the complicated adjustment to a different volume.

The devices are mainly designed to process reactive compositions with viscosities up to 2 Pas. In particular, the latter method requires reasonably low viscosities and a dosage ratio

-2 236 046 components 1: 1 maximum 2: 1. The viscosity limitations of both methods is the impossibility to process grain filled composition, except USE B8taTÍrt? S? ^Er P ^ ¹ "* ^1! predominantly fibrous, which do not affect the flow properties of the liquid components.

These drawbacks are eliminated by the device according to the invention, the dosing regimen greatly viscous ingredients which may in addition be filled with active fillers having dispersed Dála podatatně increase viscosity and thixotropy of the composition and V-filled systems may be zářísaní processed composition to viscosities of 10 ³ Pas · Vs variant · active fillers up to viscosity 10 ⁶ Pas ·

By adjustment is that the dispensing system js adapted for dispensing one, two or three liquid components of different viscosities, pumping system js depending on viscosities formed supercharged dávkovaeími pumps třívřetenovýai, by gear or piston in the necessary combinations homogenizer for viscosity to 10 ³ Pas cylindrical and for viscosities up to 10 ^ Cone-shaped waist with progressive es gap extending from smaller to larger cone diameter, stator and rotor are provided with taper cavities · A pressure sensor controlling the injection cycle and a temperature sensor controlling the homoganization process while being placed on a sliding counter ·

The solution according to the invention allows mixing in the viscosity range with high mixing efficiency. The homoganisers themselves are designed in such a way that both are interchangeable and the supply systems are essentially the same.

The inlet of the components is chosen so that the more viscous, usually more voluminous component surrounds the lower viscosity so that only the more viscous components come into contact with the cooled surfaces of the stator and rotor at the inlet to the homogenization section *

Reliability and dosing accuracy of supercharged three-spindle pump is better / + 0.5% of transported volume ·

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The other metering elements operate with the reliability and precision common to metering pumps.

For a more detailed explanation of the invention further description and attached drawings are shown in Fig. 1 - schematic representation of the whole device Fig. 2 - cross-section of a cylindrical homogenizer Fig. 3 - cross-section of a conical homogenizer pressures and temperatures.

The dosing and homogenizing devices (FIG. 1) are located on a slide bar 2 'allowing the mouth of the homogenizer 2 to be moved to the injection mold inlet in a press or the like. Dispensing pumps are also placed on the counter. The three-spindle supercharged metering pump J including the drive part j of the gear pump a and the piston pump obě both with drives. The sliding counter 11 can alternatively be fitted with a pair of supercharged three-spindle pumps 11 or 11 respectively. A pair of gear pumps 2 supplemented by a piston pump The pumps are connected by a metal piping to the cock system 6, which is part of the homogenizer block 2. The control of the cock positions and the displacement of the counter is performed by hydraulic elements. The rotor of the homogenizer is driven by a DC motor 1 »The pump outlets are fitted with pressure sensors, which regulate the pressure conditions at the outlet, to ensure perfect pump supercharging. The pressure sensors at the outlet serve as a monitoring function and ensure protection of the pumps against pressure overload. There are also temperature control Sdla in the pipeline. At the outlets of the pumps 4 and there are sampling points for separate dosing control components 10. The dosing control of the pump is performed via the homogenizer 11 with the injection valve 12 open, which is opened by a lever mechanism 11 which also serves to open the homogenizer outlet during filling over time longer breaks at work.

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A homogenizer for mixing the components with viscosities up to 10%. The waist is in FIG. In the second position, the cock 18 returns the flow of the dosed component to the inlet of the three-spindle or the spindle. The tap 17 operates in a similar manner. Both taps are coupled, but can be actuated separately if necessary. Behind the taps 17 and 18 there is an inlet with a tap 19 through which the homogenizer space can be filled or flushed with any liquid according to the technological need. The rotor and stator of the homogenizer are tempered by liquid medium through inlets 13 and 23 in cavities 15 and 16. The non-return valve 12 at the outlet of the homogenizer is opened by down pressure to the mouth of the mold inlet and closed after leaving the slide 2. . Pressure and temperature sensors 8 are located in the outflow section to control the injection cycle and mixing mode of the homogenizer, in which the temperature sensor 14 also participates. The projections of the rotor 21 and stator 22 are designed so that the rotor can be easily disassembled. The cone homogenizer of Fig. 3 is designed to homogenize compositions with viscosities up to 10 µm. The system of the inlet valves is basically the same as in the case of a cylindrical homogenizer, as well as the solution of rotor and stator tempering. The control and regulation sensors are also the same. Both types of homogenizers have the same drive and are interchangeable. The feed ring of the mixed components 24 is designed to achieve a high mixing effect and a cross section of the flow profile at the inlet to the mixing space is shown in FIG.

Fig. 5 shows the course and utilization of the monitored variables of the i.-th cycle, where in position I the duration of the injection cycle t is shown, when at time t _{poi the} position of the homogenizer outlet with the block inlet is fixed. In position II, the injection time t _v is observed and compared to position III regarding the injection pressure p _y , it is clear that the

The 236 046 injection cycle is derived from the pressure at (max) selected as the final injection pressure. The value of the initial pressure increase p _y is given by the hydraulic resistances of the filling inlets of the block and its course is therefore dependent on the solution of the inlet openings and the whole arrangement of the mold cavities.

The pressure build-up before the end of the injection is due to the filling of the mold cavities and the application of resistances in the separating plane, which must always be designed so as to allow the desired final filling pressure to be achieved.

In position IV, the course of the temperature T _y at the outlet of the homogenizer during the filling cycle is shown. In the temperature interval selected according to the technology requirements, where T _vz is the temperature guaranteeing the safe operation of the humidifier following the time lag between injection cycles and the temperature T _V p is the maximum allowable temperature at the injection time. Response speed controller homogenizer temperature level is in position, which shows that the rotor rotational speed homogenizer is controlled according to the outlet temperature in the interval ^{of n} jj j _{m n} 5 i.e. the speed at which there is achieved a good homogeneity of the composition and the speed n ^^, which are the highest possible revolutions of the homogenizer rotor. design reasons. Along with the speed change response to the outlet temperature, the flow rate of the tempering /

media - two-parameter regulation. At position VI, the course of the temperature Tg ^ in the homogenizer is indicated, which is maintained at T at the temperature č 'β between the injection cycles. This means that the temperature control at the time of injection is carried out by the sensor at the outlet of the homogenizer, while in the time between injections the control sensor within the homogenizer takes over.

Claims (2)

Apparatus for dispensing, preparing, and injecting liquid polymer compositions having viscosities of 0.01 to 10 µ Pas. Characterized in that the dispensing systems are adapted to dispense one, two or three liquid components of different viscosities, the pumping system is according to these viscosities. formed by supercharged metering pumps with three-spindle (3) gear (4) or piston (5) in necessary combinations, homogenizer (2) for viscosities up to 10 Waist is cylindrical and for viscosities up to 10 * to the larger cone diameter, the stator and rotor are provided with tempering cavities (15, 16), a pressure sensor (8) controlling the injection cycle and a temperature sensor (9) controlling the homogenization process are installed at the exit point of the homogeneous reactive composition. counter (1) · Apparatus according to claim 1, characterized in that the taps (17, 18) of the control distribution system (6) are operated jointly or individually as required.