DE1629380A1 - Mixing device - Google Patents

Description

Mixing device The invention relates to a mixing device which is suitable to add liquid components in the production of polyurethane foam Mix. The invention also relates to a device which is suitable for liquid Measure and distribute components, especially in this manufacture of Polyurethane foam.

The mixing device according to the invention has a mixing chamber with two or more inlets for liquid polyurethane foam forming components, one Outlet for the mixed ingredients and two or more rotors in this Collector for Rotation about a common axis or axes that are practically parallel to each other, are built so that the scope of each Rotors close to at least a part of the mixing chamber wall along, and at least one of these rotors has a toothing or protrusions on the circumference for mixing to support0 The inlets of the mixing chamber are usually via a valve out that in the open position the entry of the corresponding component allows the inlet of the mixing chamber and in the closed position the flow of the Diverts constituent in a secondary line, these valves for synchronous operation are arranged.

To get a really good mix, the rotors should be Shape and dimensions have that only a small space the circumference of the rotors of separates at least part of the inner surface of the mixing chamber wall. The mixing chamber and the rotors are preferably circular in cross-section, with a narrow annulus separates the inner surface of the mixing ram from the circumference of the rotors. The rotors are preferably installed so that only a small space is the end of one of the end of the adjacent rotor separates, and this space is usually, for example, through a sealing ring or by using a cushion made of compressed air.

As stated above, at least one of the rotors has protrusions its periphery is adjacent to the wall of the mixing chamber, and the other rotor or the other rotors can have similar or different projections or serrations to have. The projections are usually in the form of grooves, for example rectilinear parallel to the axis of rotation of the rotor or helically with any suitable one Slope can be arranged. The exact dimensions and the arrangement of the grooves or other projections or teeth depends to a large extent on the viscosity of the constituent, of the pressure with which it is fed into the mixer and the type of mixture required, and it can be conveniently shaped by a simple investigation can be determined.

The rotors of the mixing device are preferably driven in such a way that that a relative angular velocity between them, or if more than two Rotors used are present between adjacent rotors. Thus, if two rotors are used, for example, these in opposite directions are driven at the same or different angular speed, or but in the same direction with the same or different angular velocity, or one of the rotors can be stationary and the other rotating. Preferably however, the linear peripheral speed of adjacent rotors should be such that there is relative movement between them, thereby improving mixing will.

The rotors can be made by any conventional device, be it mechanical, be driven electromechanically, pneumatically or hydraulically. Where the rotors Sitting on concentric shafts, as shown in the drawing, will be the shafts conventionally using a system of pulleys and belts driven by an electric motor. It was found that steel and Teflon (a Polymer made from tetrafltorethylene) suitable materials for the construction of rotors, valves and the mixing device, but the choice of materials depends of course the chemical nature of the ingredients to be mixed and the conditions used, z. B. the temperature and pressure of the components.

The invention also includes a device that has a very powerful but provides simple means for distributing precise amounts of liquid, for example the mixing device of the invention. The invention also includes a device with a distributor which has an inlet and an outlet for the liquid this inlet is in connection with a container for the tallüssigkeit, furthermore with a valve that has an inlet opening that communicates with the outlet of the Distributor stands, a bypass opening, which is in connection with the container or Reservoir is, and an outlet for the discharge of the liquid speed, further with means to divert the liquid between the outlet of the distributor, the valve and the inlet of the To circulate the distributor, with a device to interrupt the flow of liquid to the manifold, further with a Means to replace the liquid discharged from the valve, the Manifold, the interruption device and the valve in accordance with a common actuating device are operated, whereby the interruption of the Flow to the manifold, the work of the manifold, liquid to the valve discharge, and adjusting the valve so that the liquid through the outlet port can flow, can be synchronized, so that successively predetermined Liquid quantities are discharged from the valve0 Since the device according to the invention not the use of conventional precision pumps with sensitive moving parts requires it can be used more generally to dispense liquid products So can very viscous liquids and suspensions of powdery solid Material can be measured in liquid, whereby the designation 11 liquid component ", as used herein includes such materials, the dispenser of the invention Device is usually a diaphragm pump, and the device for measuring and Distributing liquid is described accordingly below with particular reference on the use of diaphragm pumps as distributors, although the invention is not limited to the use of such pumps. Furthermore, although the invention in the following with particular reference to the measuring, dispensing and mixing of liquids Ingredients described for use in a polyurethane foam-forming reaction it should be emphasized that the mixing device and the measuring and distributing device also for. other liquids can be used0 in the manufacture of polyurethane foam the various ingredients are usually not in equal amounts by weight or the same volume quantities are required, but the quantities used are determined by the nature of the components and the type of foam required. As a result, the chamber volume of the diaphragm pump that is swept by the diaphragm becomes, usually different for each constituent.

The difference in volume of the various components that are present in each Operation of the mixing device can be supplied by use, if desired be brought about by diaphragm pumps, the chambers of which have different volumes, according to the amount of the various ingredients necessary for use. On the other hand, diaphragm pumps can be of practically the same (or different) capacity can be used with an actuator that allows different sizes the displacement of the diaphragm with each operation is obtained, an example of such One has furnishings, if the cylinders of the diaphragm pumps are straight are arranged, and their pistons are depressed with the help of a rod or a bar extending over the pistons from a rotatable mount at one end and is pressed down against the pistons with each operation5 is the pivot fixed, so the amount by which the pistons are depressed in the mfflmbran pumps are varied by their distance from the rotatably attached end of the rod will. EB is obvious to a person skilled in the art that depressing the piston of the Diaphragm pumps by various other mechanical, electrical or pneumatic Funds can be carried out.

The diaphragm pump can be considered, both in terms of their function and operation as hydraulic cylinders with adjustable cylinder volume, and indeed the diaphragm pump can be replaced by such a cylinder, if the volume of the ingredients to be distributed is large enough for each operation, that the leakage of liquid around the piston can be neglected, what normally the case with such cylinders, however, the volume is the at each operation to be distributed liquid relatively small, for example 4 1 or less so it is generally preferable to use a diaphragm pump.

The mixing device and the measuring and distributing device of the invention are suitable for the production of polyurethane foam, for example of a polyether polyol or polyester polyol, so-called polyether polyurethane and Polyester polyurethane. The polyurethane foam can be flexible, be solid or semi-solid.

A preferred example embodiment of an inventive Low pressure mixing device is shown in the drawing. This device is suitable for mixing two ingredients and has two valves, one for each Component.

Fig. 1 shows a section and Fig. 2 shows a plan view of the control device, which is used to achieve synchronous operation of the valves.

Fig. 3 shows a preferred embodiment of the measuring and distributing device the invention.

In Fig. 1 a mixing number 1 with a circular cross-section has a nozzle (outlet opening) 3 for the outlet of the mixed components, and two egg outlets 4 in the form of calibrated Nozzles, corresponding to the entry of the two polyurethane foam-forming components. Of course, each component can consist of more than one component by appropriate means Choosing the size of the nozzles, the injection pressure of the supplied to the mixing chamber The calibrated nozzles connect the inside accordingly the mixing chamber with two directional valves 2. Each of the valves has one Inlet, outlet and bypass port that open and close controlled by a cylindrical gate. The gate has a control arm 5, the an upright plug or pin 51 carries at its end. In Fig. 1 is the valve shown on the left side of the figure in the open position, i.e. in the position the one flow of the foam-forming component via the inlet port 16 and the nozzle 4 allows into the mixing chamber. The valve on the right is closed, i.e. it has the position in which the foaming agent is prevented from that flows through the inlet opening 15, enters the nozzle 4, but the valve leaves via the bypass opening 17, from which it is thereby returned to its source can be In the main part of the mixing chamber two rotors 8 and 9 are arranged, wherein the rotor 9 is not shown in section.

The rotors have a circular cross-section and practically the same diameter, are built in one above the other and have a very much due to the seal 14 small distance from each other.

Each rotor is closely matched to the shape or profile of the mixing chamber and is separated from this by a narrow annulus, and has a number of circumferential grooves 10 to aid mixing. The grooves of the rotor 9 are shown in Figure 1, while the grooves of the rotor 8 are not shown, since this Rotor is shown in section0 The rotors 8 and 9 are respectively concentric Shafts 11 and 12, which are driven by an electric motor 13 via the disks 13 A can be driven in the usual way on the support for the mixing device can be attached as shown in FIG.

The opening and closing of the valves 2 is shown in plan view Mechanism shown in Fig. 2 is controlled. The federal government 18, the approach 19 of the Mixing chamber is rotatable, has a flange 20, which means for controlling which carries valves 2, The part of the collar on the right side of Fig. 1 is broken off to show more clearly the control arm 5 and its plug. The valve control device has a cylindrical block 7 with an elongated hole 52, which is a connection between the upper and the lower part of the block creates the block 7 is in a circular The opening in the flange 20 is held by means of a collar 53 which is releasable on the flange 20 is attached by screws, not shown. The opening 52 encloses the Plug 51 which sits on the valve control arm 50 The part of the upper edge of the cylindrical block 7 has where it touches the edge of the flange 20 supporting it, a scale on its top surface, and the flange has a reference line on its Edge An identical control device (not shown) sits on the flange 20 diametrically opposite that described above, to control the one on the right Side valve shown in Fig. 1, a Pfleumatikylinder 6 or a similar one pneumatic or hydraulic equipment is connected to the periphery of the flange 20, in order to obtain an angular displacement of the flange around the shoulder 19 of the mixing chamber.

The typical operating procedure for the one shown in FIGS Mixing device is described below, with reference to the use at continuous supply of two foam-forming components, the corresponding through the inlet ports 15 and 16 are supplied. It should be noted that during normal operation of the mixing device, the two valves will not are simultaneously in the positions shown in Fig. 1, but they would either both open or closed, as indicated above in the following description It is assumed that both valves are initially in the one on the right-hand side of the Fig. 1, i.e. closed, with a continuous Flow of each component through the inlet port and through the bypass port flows out.

The cylindrical block 7 in the valve control device is set to normal or brought to zero position and in this position with the aid of a retaining collar 53 festgeliedten. The rotors 8 and 9 are set in motion, preferably in opposite directions of rotation, up to a constant speed is reached, and until the temperature and pressure of the flowing through the valves 2 Components have the desired values. If a load of foam material is required is, the flange 20 is at an angle to the approach of the mixing chamber with the help of Pneumatic cylinder 6 shifted, This shift pushes the side of the elongated hole 52 against the plug 51, so that the latter is moved a short distance, whereby the cylinder closure of the valve moves so that the outlet opening of the valve opened and the bypass opening is closed.

Exactly the same adjustment is carried out on the other valve, and consequently the two components flow through the two calibrated nozzles 4 in the annular space between the rotors and the inner surface of the mixing chamber, wherein the ingredients are thoroughly mixed together and the resulting mixture flows down through the mixing chamber and out of the opening at the bottom. The valves are kept in the list for as long as it is necessary to achieve the desired Amount of mixture to get, and at the end of this time both valves will through the movement of the pneumatic cylinder closed again, with the cylindrical Block 7 and plug 51 engage reversely as described above.

If the valves should not open at the same time, the cylindrical Block 7 thereby adjusted by one of the valve control devices will, that it is rotated a small amount, thereby changing the angle, with which the side of the elongated hole 52 abuts against the plug or peg 51. Through this the valve is opened either before or after the other valve, depending on how the cylindrical block 7 was rotated in its housing. Through the Block 7 attached scale can open the valves to be calibrated differently will.

The mixing device shown in Figures 1 and 2 can be simple be reinforced or expanded by one or more additional valves for adaptation to one or more other foam-forming components, with suitable control devices, generally the same as those described above can be used.

A preferred embodiment of the measuring and distributing device according to the invention is shown in FIG. 3. The facility is for keeping or storing, the accurate measurement and distribution of a liquid component involved in its manufacture of polyurethane foam is used with the aid of a mixing device in which the measured amount of the ingredient with precisely measured amounts of other foaming agents Ingredients is mixed. The facilities for storing, measuring and distributing these other components may be duplicates of the device shown in FIG except that, of course, normally a standard single mixer for all ingredients are used.

In Figo 3 is a storage container 21 for the component over a Valve 35 is supplied with the aid of a feed pump 22.

The valve 35 allows the constituent on a constant To maintain the level in the container 21. The container 21 is part of two in * correlation standing circles. The first comprises the container 21, a pump 23, a valve 36, a heat exchanger 24 and a valve Di, and it is with the help of this circuit possible to keep the contents of the container 21 at a constant temperature keep that they are circulated through the heat exchanger. The container 21, the Heat exchanger 24 and valve 34 form part of the second circuit, the also shut-off valves 27, a diaphragm pump 25, a mixing device 26 and a Valve 33 includes. The mixing device 26 has a two-way valve, which is shown in the in Fig. 3 prevents the liquid to the mixing chamber and thus flows to the outlet 32, but it directs the liquid into a secondary line, so that it flows from the diaphragm pump 25 back to the heat exchanger 24. In the other position of the valve allows fluid from the diaphragm pump to the misclic chamber and thus to the outlet 32 flow.

The mixing device usually has that shown in FIGS. 1 and 2 shown shape.

The diaphragm pump 25 has upper and lower chambers 28 and 29, between which the circumference or the edge of a membrane 30 is clamped, and this on the head a piston 37 is attached. In the drawing the piston is in its uppermost position Position shown and the membrane is completely pulled up into the upper chamber 28, so that a maximum volume is created under it. The top of the piston 37 carries a freely rotatable contact wheel 39 which is in contact with a rod 31, the wheel being urged against the rod by a spring 38. The rod or the bracket 31 is rotatably mounted at one end on a horizontal pivot 40. The other end is connected to a piston 41 which runs in a cylinder 42, these together form a means for turning the support 31 around its pivot to move. In the drawing, the rod or bracket 91 is pivoted from its End tilted off upwards. Between the part of the rod that contacts the wheel 39, and the end of the rod attached to the piston 41 is a second wheel 43 shown, the contact wheel of a device for measuring and distributing the second component is.

The valves 33 and 34 form means for controlling the throughput of the component through the various circles.

The pumps 22 and 23 can be of any known type, and it is not necessary that they are particularly accurate in terms of their delivery rate.

The device of Figure 3 relates to the measurement and distribution of a individual foam-forming component, which is fed to the mixing device 26. In the following description of the operation of the device, it is assumed that the other foam-forming ingredients are measured by like facilities and be distributed, their relationship to. the device of FIG. 3 by the position of the contact wheel 43 is displayed.

The said second component is usually in the same way fed to the mixing device 26, as shown for the first component in Fig. 3, the flow of each component having its own inlet, outlet and bypass opening in the mixer. The actuating means for the control piston 41 can also be those relating to the shut-off valve 27 and the mixing device control of each component, so that the components are synchronized in the chamber can be fed to the mixing device.

The operation of the device shown in Figure 3 is typically as follows. At start-up, the membrane 30 is in its fully retracted position, and that valve of the mixing device is set so that its binla opening in) with the bypass opening. ie are described in detail below the membrane and the valve of the instrument normally turn to the desired Positions that follow the completion of a previous mixing cycle.

The liquid component is pumped 22 into the container 21 introduced until the level of the component in the container is a desired one Value reached when valve 35 is closed, then pump 23 is switched on, with valves 34 and 36 open 0 When constant conditions are reached, the usual actuation device for the devices is operated, which the control both components to close the shut-off valve 27 and the piston 41 moves down and takes the rod 31 with it. The rod 31 thus pushes the piston 37 down, causing the components in the chamber of the diaphragm pump 25 squeezed out of this chamber and pressed into the chamber of the mixing device will.

The actuating device acts simultaneously on the device which controls the flow of the other component, creating a predetermined amount injected from these into the mixing chamber through the corresponding inlet opening becomes, practically simultaneously with the injection of the first component, and the Ingredients are mixed together before being put into a mold, container, or other receiving devices are brought into which the polyurethane foam is located can develop.

If the contents of the diaphragm pump have been discharged, so Find the following connection processes take place: 1. The actuator stops work so that the piston in the cylinder 42 under the influence of the spring 38 upwards increases, which, if necessary, can be supported by other institutions, whereby the piston 37 and its membrane 30 attached to it up to the top climb up around the chamber of the diaphragm pump. The spring 38 continues the contact wheel 39 to press against the carrier 31.

2. The valve of the mixing device 26 is reset so that the Inlet port is brought back into communication with the bypass port and from the mixing chamber is separated or cut off0 5. The shut-off valves 27 are opened again.

Through these three processes one gets a flow of the constituent again through the chamber of the diaphragm pump, through the mixing device via the bypass flow and back to the reservoir via the heat exchanger 24. It also gets fresher Component as required in the storage container 21 by opening the valve 75 and fed using pump 22 to balance the amount of ingredient, which has flowed off into the mixing device. The entire cycle can then be carried out by using of the actuator are repeated, usually in the form of an electromechanical Control is present.

Claims (10)

Claims 1. Mixing device suitable for mixing liquids Components in the production of a polyurethane foam, with a mixing chamber, the two or more inlets for liquid polyurethane foaming ingredients and has an outlet for the mixed ingredients, characterized in that the mixing chamber has two or more rotors (8,9) which rotate around a common one Axis or around axes that are practically parallel to one another, are installed, -so that the circumference of each rotor is close to at least a portion of the mixing chamber wall drifts past, and that at least one of these rotors has circumferential projections or teeth has to aid mixing. 2. Mixing device according to claim 1, characterized in that the Supply to each of the inlets (4) via a valve (2) success, which is in its open Position the entry of the corresponding component into the DinlaA of the mixing chamber allows and that in its closed position the flow of the component in a Bypass line (17) diverts, and these valves can be operated synchronously. 3. Mixing device according to claim 1 or 2, characterized in that that two rotors are present, one of which sits on a shaft (12) which is arranged within a hollow shaft (11) on which the other rotor is seated. 4. MischvorrichtuAg according to claim 1, 2 or 3, characterized in that that all rotors have circumferential projections or teeth to facilitate the mixing to support. 5. Mixing device according to one of the preceding claims, characterized characterized in that the projections or teeth by helical Grooves or grooves are formed. 6. Mixing device according to one of claims 2 to 5, characterized in that that the device for synchronous command each valve drove the valves a slotted Member (7), the slot or recess (52) of which in a plug or peg (51) can engage, which is operably connected to the valve, and further means are provided to move the slotted links in synchronism. 7. Device for measuring and distributing a liquid in successive equal amounts, characterized in that it comprises in combination the following parts; a manifold (25) having an inlet and an outlet for the liquid, wherein this inlet in connection with a reservoir (21) for the liquid stands, a valve (26) having an inlet port which is in communication with the outlet of the manifold is a bypass orifice that communicates with the reservoir stands, and an outlet opening (32), for discharging the liquid, a device (23) to divert the liquid between the outlet of the manifold, the valve and the To circulate the inlet of the manifold, means (27) to allow the flow of the liquid to interrupt the manifold, and a device to discharge discharged from the valve Fluid to replace, and a conventional actuator to synchronize to bring about the following processes, a) the interruption of the flow of the liquid to the manifold, b) actuation of the manifold to discharge liquid to the valve, c) adjusting the valve so that the liquid flows through the outlet opening can. 8. Apparatus according to claim 7, characterized in that the distributor is a diaphragm pump. 9. Apparatus according to claim 7 or 8 ,, characterized in that daCo the reservoir or container for the liquid and means (24) to to maintain the temperature of the liquid between the bypass port of the valve and the distribution inlet are arranged. 10. Apparatus according to claim 7, 8 or 9 in combination with the mixing device according to one of claims 1 to 6, characterized in that the valve of this device, which is one of the valves of the mixing device, and the outlet opening of the valve of this device are in communication with the mixing chamber of the mixing device. Lee rse 1 te