FR2554914A1 - Drying hopper for granular products - Google Patents

Abstract

a) Drying hopper for granular products comprising a reserve 1 equipped with hot air distribution channels 4 forming spouts 5 equipped with rotary extractors 6. b) Drying hopper for granular products characterised in that the discharge hopper 3 is equipped with upper 9 and lower 10 level indicators avoiding blockage of the hot air intake channel 7.

Description

 The present invention relates to a drying hopper for "r'l" granular products comprising a reserve box for granular products to be dried, distribution ducts for ventilation by hot air over the entire surface of the box, these ventilation qaines serving in addition, drain buckets which are fitted with extractors.

Various dryers for granular products are known, equipped with hot air blowing ducts with tilting extractors.

These dryers have reserves in which are installed ducts for blowing and extracting air over the entire height. The hot air feeds these blowing pipes through external pipes, the air used for drying then being evacuated by other extraction ducts to external pipes. The used drying air is not used to preheat the product to be dried, it does not pass through all the product to be dried.

The present invention is characterized with regard to a drying hopper with air distribution ranges also serving as drainage buckets equipped with rotary extractors.

The innovation consists of the following points:
The reserve box has a total upper opening allowing it to be loaded either by a line through which the granular product to be dried flows, or by a mechanical loader equipped with a tilting bucket. The ventilation ducts equipped with extractors seal with the emptying hopper.

Whether the reserve is full or little filled, the hot air supply pipe installed in the drain hopper supplies hot air to the blowing pipes located between and above the extractors. The hot air thus blown passes through the product to be dried, drying the bottom of the product as a priority.

This air gradually cools through the layer of product to be dried, this cooling being effected by the evaporation of the water extracted from the product. There is no problem if this water condenses on the product at the top. We are then at an optimum thermal efficiency. Thermometers indicate the temperature of the hot air and the product being dried. The temperature of the hot air is chosen according to the temperature tolerable by the product to be dried. A certain balance between the temperature of the hot air and of the product indicates that the product is dried at the chosen convenience.

The emptying is carried out by putting the rotary extractors into operation. Drying may or may not be interrupted.

High and low level indicators cause the extractors to work or stop. The high level stops the rotary extractors while the low level puts them into operation. These level indicators thus prevent the main supply of hot air from being obstructed by the extracted product and waiting in the hopper lower.

The drain rate is regulated by a flow rate adjustment valve.

The invention will be described in more detail with reference to an example of the use of the drying hopper for granular products in accordance with the invention shown in the accompanying drawings, in which:
Figure 1 shows in vertical section, by way of nonlimiting example, an embodiment of the drying hopper for granular products.

Figure 2 is a sectional view along the horizontal plane II of Figure 1, seen from above.

The drying hopper for granular products has a reserve box 1. This box is equipped with a control thermometer 2.

The reserve bottom is isolated from the drain hopper 3 by hot air distribution ducts 4.

These ducts form drain bowls 5 which are fitted with rotary extractors 6.

The hot air is blown into the drain hopper 3 by an air inlet 7 which passes through this hopper, its end being obstructed by the slope of the hopper itself.

The air temperature is controlled by the thermometer 8.

In the lower emptying hopper are installed the high-level 9 and low-level indicators 10 which thus avoid obstruction by the dried product of the hot air inlet sheath 7.

The drain flow is ensured by a valve 11.

Claims (2)

R E V E N D I C A T I O N S 10) Drying hopper for granular products comprising a reserve of products to be dried (1) isolated from the emptying hopper (3) by air distribution pipes (4) also serving as emptying buckets (5) equipped with 'rotary extractors (6), the general hot air supply duct (7) being located in the drain hopper. 20) Drying hopper for granular products according to claim 10 characterized in that it comprises in the emptying hopper (3) a high level indicator (9) and a low level indicator (10) which avoid obstruction de-ll hot air intake duct (7).