EP1435499A2 - Apparatus for drying bulk materials - Google Patents

Abstract

The assembly to dry loose materials (31), e.g. plastics granules, has a funnel-shaped container (29) with adjustable side walls (30) to set the volume held in it by altering the angle between them. A membrane dryer (12) takes compressed air from a compressed air system (10) for drying, which has been cleaned by filters (13,14). A throttle (16) controls the flow of drying air according to the volume of material in the container. The membrane dryer, to extract moisture from the air to dry the granules, has a drying stretch (17), and a stretch (24) for a flushing gas at the side of the drying stretch away from the membrane (18).

Description

State of the art

The invention relates to a device for drying bulk goods an at least partially funnel-shaped container of the genus Claim 1. In addition, the invention according to claim 8 relates to a Drying device for bulk goods, which has a dehumidifier for the Coming use dry grass.

Drying devices for drying bulk goods such. B. Plastic granules are known, inter alia, from DE 3234431 C2. The Granules to be dried are in a container that is pointing downwards a granulate removal tapered funnel-shaped and from above with the Granulate is loaded. To dry the granulate, it is used Dry gas, in particular heated air passed, which on the granules adhering moisture entrains. To improve the drying result the dry air is passed through a dehumidifier beforehand.

The drying devices are generally for a specific one Flow rate of bulk material designed. The plastic granulate is after the Drying supplied in particular plastic processing machines. Before they are often mixed with other components, the one represent a significantly lower percentage in the desired raw material. Conventional dryers are used for the pretreatment of additional granules very small amounts are only of limited use. Will this Problems with the drying result may not be completely filled of the granules occur because the passage of the dry air is no longer in takes place homogeneously. On the other hand, full filling is the Drying device with granules due to the time-dependent thermal degradation of the bulk material is not possible. The drying plant leaves the capacity of the desired amount of dry granules to adjust. The dehumidifier in particular remains when the Drying capacity largely unused because it is in the event of Plant utilization must be designed. For dehumidifying the dry air often come regenerable cartridges with moisture-absorbing Fabrics used as an additional unit for the granule dryers assigned.

The object of the invention is to provide a drying device for To create bulk goods that optimally match the to be dried Granulate amount can be adjusted, especially for small dry amounts is suitable, and a high degree of flexibility in use, in particular with regard to different locations.

This object is achieved by the features of claim 1 claimed a drying device which as a membrane dryer Has dehumidifier.

Advantages of the invention

The inventive device for drying bulk goods according to Claim 1 represents a solution to enable its flexible use. The drying device according to the invention has a funnel-shaped Container in which the bulk material to be dried is filled and removed can be. Furthermore, the passage of a dry gas through the Containers possible in such a way that the dry air flows through the bulk material. This device also has a dehumidifier, which in particular can also be structurally integrated into the system unit of the drying container can. This is made possible by providing a membrane dryer Dehumidification of the dry air, as this is compared to the conventional one dehumidifying devices mentioned above by a small space requirement is marked. It is a purge gas connection and a purge gas outlet provided the passage of purge gas through a purge section enable. The rinsing section is turned away from the drying section Side of the membrane formed. The purging gas is therefore the by Moisture penetrating membranes. This creates one Partial pressure difference in humidity between the two sides of the Membrane, whereby the function of the membrane dryer is achieved.

A particular embodiment of the invention provides a membrane dryer before, which has two dry gas connections, the passage of the Dry gas through one of moisture-permeable membranes formed drying section allows. The cross section of this drying section is selected in such a way that a Throttling effect is achieved. The passed dry gas relaxes therefore from a higher pressure level in front of the membrane dryer to one lower pressure level after drying. By relaxing the Dry gas, the moisture is separated on the membrane walls and diffuses through the membrane walls. The drying section can e.g. B. from Hollow fiber membrane tubes are formed, such as this. B. from DE 196 33 177 A1 are known. After the dehumidification has taken place, the drying gas becomes Container for drying the bulk material supplied.

The purge gas can advantageously the dry air line behind the Membrane dryer can be removed. For this purpose one branches Purge gas line from the dry gas line leading to the purge gas connection of the membrane dryer. Condition for successful dehumidification of the Dry gas is that the purge gas flow is smaller than the dry gas flow, so that the drying container has a dry gas flow at all can be put. For this purpose is in the purge gas line Throttle device provided, which depends on the required Can be set.

It is also advantageous to have a heater for the in the dry gas line Provide dry gas. This allows the drying gas to be used for the Drying the granules to heat up to the ideal temperature.

According to a particular embodiment of the inventive concept, this is Output of the dry gas from the container downstream of a filter. This retains particles that the dry gas flows through Bulk goods. The filter thus prevents stress on the Working environment of the dryer due to possible granulate dust. The latter can e.g. B. by providing a cyclone again for the Process can be recovered.

A special embodiment of the invention provides that the drying gas Compressed air system and the compressed air line Feed membrane dryer. Via a dry gas throttle device, which is preferably installed in the compressed air line, the required Dry air volume can be set. The dry gas throttle can preferably be designed as a clock valve, which is controlled by time Switch the amount of compressed air reduced, with the open position of the Dry gas throttle body the full pressure of the supply of compressed air Available. This ensures that the optimal pressure drop for drying the drying gas is achieved. The Compressed air must be cleaned before being fed into the membrane dryer. The filter means provided for this can be constructed in two stages. In the Preliminary stage is z. B. cleaning of coarse particles by a paper filter reached, the fine stage mainly serves to de-oil the compressed air.

The arrangement with a filter at the dry air outlet of the container and the Extracting the dry air from a compressed air system creates an open one Circulation of the dry gas. Alternatively, the compressed air can also within a closed dry air circuit in the device itself be generated. For this purpose, the dry air after leaving the container Pressure generator fed again to the membrane dryer to go through again. An open circuit has the advantage that Only the heating without reaching the desired dry gas temperatures Additional use of return air coolers for that from the container escaping dry gas is necessary. The lower component effort saves costs and leads to a compact design of the device.

According to a further embodiment of the invention, the one described Device operated with a controller. The controller can e.g. B. the Signals from a temperature sensor between the heater and tank is attached, a temperature sensor at the dry gas outlet of the Container and a moisture sensor behind the exit of the Evaluate the membrane dryer. About the residual moisture of the dry gas behind the purge air throttle element can be controlled by the membrane dryer, whereby this way the drying container is supplied with dry air of constant residual moisture Can be made available. The temperature sensor behind the heater can be used to control the temperature of the dry gas. The Temperature sensors are still used for a temperature comparison of the Dry gas used before and after passing through the container. hereby a heat balance can be drawn up, from which conclusions can be drawn about the course of the drying process are possible. The control unit can continue with be connected to the outlet opening of the container and the discharge of Arrange dried granules depending on their moisture. The Operation of the device is both in batch mode and in continuous operation conceivable.

Due to the small size and the simple structure of the different The device can be components in a housing or support frame integrate. The result is an arrangement of small size and small Weight that is flexible in handling. In this way, the The device according to the invention is used in a short time at the respective locations come where the supply of small amounts of granules is desired. Thereby can achieve an optimal degree of utilization of the device, which the Efficiency in daily operation increased. For the compressed air variant of the The device is only a compressed air connection and an electrical one Connection for control and heating necessary. Connections this Art are available at most conceivable locations, so none Modifications are necessary for the use of the device. By adjusting the Container volume, the amount of dry air can be Reduce the dry air throttle element to a minimum. The system is consuming So only as much compressed air as this for the degree of filling necessary is. This contributes to the economic operation of the device according to the invention.

These and other features of preferred developments of the invention go beyond the claims also from the description and the Drawings, the individual features each individually or to several in the form of sub-combinations in the embodiment of Invention and to be realized in other fields and advantageous as well Protectable versions can be represented, for which protection here is claimed.

drawing

Figur 1

ein Blockschaltbild einer Vorrichtung, die durch ein Druckluft-Versorgungssystem gespeist wird, einen Membrantrockner zur Entfeuchtung der Trockenluft aufweist und deren Behälter verstellbare Trichterwände aufweist,

Figur 2

einen trichterförmigen zum Teil aufgeschnitten dargestellten Behälter zur Trocknung von Schüttgut in der Seitenansicht und

Figur 3

den Behälter gemäß Figur 2 in der Ansicht von unten.

Further details of the invention are described in the drawings using schematic exemplary embodiments. Show here

Figure 1

2 shows a block diagram of a device which is fed by a compressed air supply system, has a membrane dryer for dehumidifying the dry air and the container of which has adjustable funnel walls,

Figure 2

a funnel-shaped, partially cut open container for drying bulk goods in side view and

Figure 3

the container of Figure 2 in the view from below.

Description of the embodiments

The figure 1 can be seen which way the dry air through the Device for drying bulk goods takes. The dry air becomes one Compressed air supply 10 removed and via a compressed air line 11 Membrane dryer 12 supplied. A pre-filter 13 is located in the compressed air line 11 for separating particles and oil separator 14 for separating the in Compressed air located oil. The oiler 14 has one Return line 15, the separated oil to the compressed air system again supplies. Furthermore, a clock valve as a dry gas throttle element 16 in the Compressed air line 11 is provided. The dry gas flows through the Membrane dryer 12 and passes a drying section 17, the tubular membranes 18 is formed. When going through the Drying section, the drying gas releases most of its moisture and is passed into a dry gas line 19, where it contains a moisture sensor 20 happens to determine the residual moisture. There is in the dry gas line further a branch of a purge gas line 21 leading to a Purge gas connection 22 leads to the membrane dryer 12. As a purge gas throttle 23, a solenoid valve is provided in the purge gas line 21, which the Purge gas flow limited by a purge section 24 of the membrane dryer 12. The purge gas absorbs the moisture passing through the membrane and leaves the membrane dryer 12 through a purge gas outlet 25. Das Dry gas passes through a dry gas heater 26 and one Temperature sensor 27 in the dry gas line 19, to then by a Entrance 28 to be fed to a container 29. The container 29 has adjustable funnel walls 30 and is filled with bulk material 31. The Dry gas flows through the bulk material 31 from the bottom up and is through an outlet 32 passed from the container. There is another one here Temperature sensor 27 and a filter 33. The bulk material 31 can by a Feeder 34 can be filled into the container 29 and through an outlet opening 35 can be removed again. Feed 34 and outlet opening 35 are lockable.

The container 29 has a double wall 54 through which the dry air alternatively, can be routed via a bypass line 55. You then reached via bushings 56 the entrance 28.

A controller 36 is provided for operating the device. about Control lines 37, this control evaluates the signals of the Moisture sensor 20 and the temperature sensors 27. Of this Evaluation is the circuit of the dry air throttle element 16, the Purge air throttle element 23, the dry air heater 26 and the outlet opening 35 dependent. In addition, other sensors such. B. a Level sensor for the bulk material (not shown) can be arranged. The Control also allows the device to be manipulated manually.

Figure 2 shows an embodiment of the funnel-shaped container 29. This provides for a self-contained system, which the feed 34 and the outlet opening 35 for the bulk material and the entrance 28 and the Has outlet 32 for the dry gas. The container has a lid 38, which releases the feed 34 and an adjustment of adjustment sides 39 allowed. The adjustment sides 39 form together with fixed wall parts 40 the surfaces of the funnel-shaped container. At the top of the fixed wall parts 40, a catch bar 41 is attached, with lugs 42 interact on the adjustment sides 39. On the bottom are the Adjustment sides 39 in slots 43 in an intermediate floor 44 of the container plugged in. These slots act like a hinge, so that by light Lifting the adjustment side 39 and disengaging the lugs 42 adjust the adjustment sides 39 are tiltable in their inclination. By snapping into the catch bar 41 the adjustment sides 39 are fixed. The intermediate floor 44 has one in the middle Through opening 45 for the bulk material. To fill the container with Bulk goods are closing means 46, z. B. a screw connection and the lid removed. As a result, the feed 34 of the container Approved. At the same time, with the cover 38 open, the adjustment of the Funnel inclination.

The design of the fixed wall parts 40 is clear from FIG. The one of them is arranged obliquely and has two kinks 47, ie it consists of three flat wall parts. By the inclination of the resulting Triangular surfaces 48 ensure that side edges 49 (in FIG. 3 shown in dashed lines) of the adjustment surfaces 39 always on the inside of the Triangular faces 48 abut. The other fixed wall part 40 is designed vertically and has a maintenance opening 50 (see Figure 1) is closed by a maintenance cover 51 are also on the container Fastening bores 52, which integrate the container in one Allow housing or on a frame attached. With help of a Mounting flange 53, the container z. B. on one Attach plastic injection molding machine, the outlet opening with a not shown inlet of the injection molding machine communicates.

Claims (7)

Device for drying granular or powdery solids, which has an at least partially funnel-shaped container (29) with a feed (34) and a closable outlet opening (35) for the solid, with an inlet (28) to which a dehumidifier for the dry gas is connected upstream and an outlet (32) is arranged such that the dry gas flow leads through the solid, characterized in that the dehumidifier is a membrane dryer (12) with a drying section (17) for the drying gas and a purge gas section (24) for purge gas , wherein the purge gas section is formed by the side of the membranes (18) facing away from the drying section (17). Apparatus according to claim 7, characterized in that the drying section (17) formed by moisture-permeable membranes (18) is designed as a throttle for the drying gas. Apparatus according to Claims 7 to 9, characterized in that a purge gas line (21) provided with a purge gas throttle element is provided, which branches off from a dry gas line (19) connecting the membrane dryer (12) and the container (29) and with a purge gas connection (22) connected is. Device according to one of claims 7 to 10, characterized in that the dry gas line (19) has a dry gas heater (26). Device according to one of claims 7 to 11, characterized in that the output (32) is followed by a filter (33). Device according to one of claims 7 to 12, characterized in that the membrane dryer (12) is connected to a compressed air line (11) which has a dry gas throttle element (16) and filter means (13, 14) for cleaning the compressed air, and the device one Containers (29) according to any one of claims 1 to 6. Device according to one of claims 7 to 13, characterized in that in the dry gas line (19) a moisture sensor and a temperature sensor (27) in the dry gas flow in front of the entrance (28) and after the exit (32) are provided, which by means for Control (36, 37) of the dry gas throttle element (16), the purge gas throttle element (23), the dry gas heater (26) and / or the outlet opening (35) are connected.

Images