SU892162A2 - Vibration dryer for fine materials - Google Patents

Description

(54) CRASH DRYER FOR LOW-DYED MATERIALS

I

The invention of fires to continuous-flow dryers in viral {tweeted dense layer with conductive heat supply and is intended for drying fine materials, such as fluorite concentrate, abrasive powders, etc.

Vibro-gravity dryers for finely dispersed materials are known, containing a vertical shaft with a heat exchange surface disposed therein, devices for removing vapor released from the material being dried, material for charging and loading, and a vibrating member. In this case, the device for removal of steam is implemented in the form of a channel combined with a heat transfer surface. Joint actions, creating conditions for a stable moving material in the form of a dense layer, arise as a result of vibration of the heat exchange surface 1.

However, these dryers have a relatively low efficiency.

Vibrating killers are also known in which part of the heat of the resulting vapor is utilized to increase thermal efficiency. An additional bundle consisting of heat pipes 2 is located in the vibrating driers under the tag-exchange surface.

The common principle in the said sweethearts is the principle of conductive drying of fine materials in the extragravity layer, and the difference lies in the organization of

10 vapors formed and the method of transmitting vibratory effects to the layer. Prichaschialnye difficulties, I conclude in the organization of a stable movement of material and uniform removal, in these dryers are resolved.

15

A disadvantage of the known dryers is the relatively low intensity of heat and mass transfer associated with the nature of the washed cylindrical tubes of the heat exchange surface in the transverse flow of the granular material. These zones are practically excluded from heat transfer.

The presence of a streamlined hermetic compartment in the frontal zone, as well as vibro probes, can to a certain extent improve the conditions for washing, but will lead to significant structural and operational complications.

According to the main auth. No. 597905 is well-known, a vibratory dryer for fine materials, containing a vertical shaft with heat exchangers in the form of hollow tubes, between which vibrating steam collectors are installed. The steam collectors are connected to the vibrator by the rods located in the steam discharge pipes on the outside of the shaft 3.

The purpose of the invention is the intensification of heat and mass transfer and the improvement of steam removal conditions by tangentially injecting part of the coolant in the amount of 4-6% of the total flow rate from the heat exchanger cavities to the base of the stagnant zone of the material.

The goal is achieved by the fact that in the upper part of each heat exchanger tube there are holes, located along the tube forming at an angle of 20-25 ° from the frontal point, and the step between the holes is 2-2.5 of their diameter.

In addition to the destruction of the stagnant zone, the injection of part of the coolant into the moving layer improves the conditions of vapor filtration. in the direction of the steam collectors.

FIG. 1 shows schematically a descriptive vibration dryer for fine materials; in fig. 2 - the same, side view; in fig. 3 — node 1 in FIG. 2

The vibrating dryer contains a vertical shaft 1 with beams of tubes 2 placed therein for kontststivnogo heat supply to the material. The layout of the chess pipes that provides intensive mixing; The material is heated by a gas coolant, for example, combustion products. In the upper part of each pipe 2, holes 3 are made with a diameter of 0.2-0.3 mm, located along the generator with a pitch equal to 2-2.5 times the diameter of the holes. Holes 3 are located along the line forming the pipe 2 at an angle of 20-25 ° from the frontal point. Steam collectors 4 are located between the pipes. They are connected by means of vertical rods 5 with a vibrator 6.

The rods 5 are located in the steam discharge pipes 7 on the outside of the shaft 1. The material is drained from the vibrating dryer through the plug-in device 8. The furnace, the device for feeding the heat carrier to the pipes and its aerodynamic path are not shown conventionally.

Vibration works as follows

2162.4

Wet material is loaded from above into mine I and under the action of vibrographic forces in the form of a dense layer moves downwards. As a result of contact with the hot surface J of the pipes 2, the material is heated and the moisture contained therein evaporates. The destruction of the stagnant zone formed in the frontal part of the pipe is carried out by part of the heat transfer fluid tangentially injected into the 4tO 6% of the total flow from the pipe cavity through the holes 3 located along the generator of each pipe at an angle of 20-25 ° from the frontal point. This angle, found experimentally, characterizes the boundaries of the stagnant

j frontal area. The steam generated during drying, as well as the heat carrier injected into the layer, diffuses in the direction of the steam collectors 4 and is discharged through the steam discharge pipes 7 to the atmosphere. Vibration of the steam collectors 4 is carried out with the help of the vibrator 6 by means of rods 5, located in the steam discharge pipes 7 on the outside of the shaft 1.

The stable movement of the material in the form of a dense vibrogravitational layer and the regulation of its speed is ensured by the appropriate vibration parameters created by the vibrator 6, the temperature of the heat exchange surface of the pipes 2 and the design of the discharge device. The destruction of the stagnant zone in the frontal part of heat pipes will increase the heat exchange rate by approximately 20-30%, which will reduce the size of the installation, as well as increase its efficiency.

Claims (3)

1. Authors certificate of the USSR G 519918, cl. F 26 B 17/16, 1974. 2. USSR author's certificate number 659862, cl. F 26 B 17/16, 1977. 55 3. USSR author's certificate No. 597905, cl. F 26 B 17/10, 1976.