JPH0675643B2 - Centrifugal sprayer for spray dryer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement of a rotary disk type spray dryer, and relates to a centrifugal sprayer for a spray dryer capable of achieving high efficiency and miniaturization. .

[Prior Art] Conventionally, a stock solution to be dried is sprayed at a high pressure onto the surface of a rotating disk of a centrifugal sprayer that is rotationally driven at a high speed, which is provided in the central portion of the ceiling of a drying chamber, and is dispersed in high temperature air for drying for a moment. A rotary disk type spray dryer having a structure for drying is used. In this centrifugal sprayer, the axis for rotating the rotary disk is located at the center of the rotary disk. Therefore, the injection nozzle for the stock solution must be provided at a position off the axis, and the contact with the rotary disk must be avoided. There was a problem that the radius was shortened and the drying efficiency was poor.

Originally, about 97% of the quality of the dried product obtained by this type of spray dryer, except for special ones, was irrelevant to the shape of the spray disk and was mostly due to the peripheral speed of the rotary disk. Generally, the most frequently used rotating disk has a peripheral speed of about 90 m / sec.For example, in the case of a spray dryer having a stock solution treatment capacity of 1,000 kg / hour, the rotating disk has a diameter of 180 mmψ and a rotation speed of 10,000 rpm. The peripheral speed is 70m / sec, and the required motor horsepower at this time requires 11KW.

Further, it is technically difficult to make the spray angle of the conventional rotary disk narrower than 170 degrees, so the diameter of the drying chamber becomes large in order to secure the flight distance of the spray droplets generated by the rotary disk, Had the problem of increasing in size.

[Problems to be Solved by the Invention] The present invention has been made in view of the above problems, and an object thereof is to improve not only the drying efficiency of an apparatus but also the energy efficiency. Moreover, it is an object to realize the miniaturization of the apparatus.

[Means for Solving the Problems] A centrifugal sprayer for a spray dryer according to the present invention is an external rotary drive mechanism for a centrifugal sprayer for a spray dryer for spraying and drying a stock solution to be dried in a dry air atmosphere. A hollow shaft that is rotatable by means of a shaft is installed, and a plurality of thin pipe-shaped propellers for injection are provided in the downward angular direction of the vertical section 30 to 60 degrees from the horizontal position with respect to the propeller blade mounting seat fixed to the lower end of the hollow shaft. The gist of the present invention is that the blades are arranged so as to project radially evenly and communicate with the undiluted solution supply pipe shaft, and the undiluted solution supply pipe line is formed through a rotary pipe joint provided at the upper end of the undiluted solution supply pipe shaft. It is a thing.

Preferably, in the above configuration, the gist is that a spray nozzle member is provided at each of the injection propeller blade tips protruding from the propeller blade mounting seat.

Further, each of the injection propeller blades projectingly provided on the propeller blade mounting seat is configured so that the projecting angle can be adjusted with respect to the central axis.

[Operation] A dryer having a centrifugal sprayer configured as described above supplies a liquid to be dried while rotating a stock solution supply pipe shaft at a predetermined rotation speed by a rotation driving device such as an external motor, and supplies the liquid to be dried to an upper end of a drying chamber. The atomized stock solution is jetted and mixed from the tip of the propeller blade into the dry high temperature gas atmosphere jetted from the hot air jetting device provided, and the heat is instantaneously exchanged to evaporate the water content and dry powder the stock solution. .

[Embodiment] An embodiment of the centrifugal sprayer for a spray dryer according to the present invention will be described below with reference to FIGS. 1 to 3.

As shown in FIG. 3, the centrifugal sprayer 1 of the present invention has a drying chamber 2
An annular hot-air jetting device 5 fixed to the upper wall 4 so as to be located on the central axis of the cylindrical portion 4 continuous with the upper edge of the inverted conical hopper 3 and formed on the lower surface of the upper wall 4. Is provided in the annular shape of the hot air jetting device 5 so as to face the jet port, and a drying gas supply port 6 is opened on one side of the hot air jetting device 5 and above the discharge port 7 formed at the lower end of the hopper 3. Is provided with an exhaust pipe 8 having a conductive opening outside the drying chamber.

The centrifugal sprayer 1 rotates the stock solution supply pipe shaft 16 through the bearings 14 and 15 provided on the mount plate 11 and the support wall 13 on the shaft center of the cylindrical main body frame 12 having the mount plate 11 fixedly mounted on the upper end. A pulley 24 that is freely shaft-mounted and has an upper end that is rotatably connected to an external rotation drive device (not shown) such as a motor, and has an oil supply port 17 provided on an upper bearing 14 and an oil seal provided on the outer side thereof. It is opened between 14a. Further, the lower bearing 15 is fastened with an oil cutting nut 19 having a water draining edge to be fitted on a collar edge 18 protruding from the bottom wall of the main body frame 12, and rotates in cooperation with the stock solution supply pipe shaft 16. In addition, the oil suction pipe communicating from the vicinity of the lower end of the oil sump 29 in the inner cavity of the main body frame 12 through the mount plate 11
20 are provided. Reference numeral 21 is a propeller blade mounting seat fixed to the lower end of the undiluted solution supply pipe shaft 16, and the propeller blade mounting seat is provided.
21 is a thin pipe-shaped eight propeller blades for injection 22,22 ... protruding in a downward angle direction of about 45 degrees in a vertical cross section, which are evenly arranged radially with respect to the shaft, and with respect to screw holes 23,23. The undiluted solution supply port of the rotary pipe joint 25 provided at the upper end of the undiluted solution supply pipe shaft 16 that is threadedly protruded and communicates with the undiluted solution supply pipe shaft 16 respectively.
A stock solution supply path 27 is formed via 26.

When pressure spraying is required in addition to rotary spraying, a nozzle member having a small diameter nozzle hole 30 at the tip of each propeller blade 22 arranged on the propeller mounting seat 21 as shown in FIG.
28 is screwed and used.

The centrifugal sprayer 1 having the above-mentioned configuration has upper and lower bearings 14,1.
In order to maintain the normal bearing function of 5, oil is supplied from the oil supply port 17 and the oil that has accumulated in the oil sump 29 is discharged and circulated through the oil suction pipe 20. The stock solution supply port 26 is rotated by the drive device while rotating the stock solution supply pipe shaft 16 through the pulley 24 at a predetermined rotation speed.
To supply the liquid to be dried. Drying room 2 at this time
From the hot air jetting device 5 provided at the upper end of the dry hot gas is jetted toward the vicinity of the propeller blades 22,
It mixes with the mist-like stock solution ejected from the propeller blades 22 and heat is instantaneously exchanged to evaporate the water content, whereby the stock solution is dried and powdered.

According to the above configuration, since the rotating shaft of the centrifugal sprayer 1 is the stock solution supply pipe shaft 16, the stock solution to be supplied can be supplied from the central axis position of the sprayer 1, and an ideal spray structure is provided. In addition, the pipe for introducing the undiluted liquid supply can be omitted, and the device can be simplified.

In the centrifugal sprayer 1 having the above-described configuration, when the length of the injection propeller blade 22 is configured such that the end rotation locus has a diameter of 500 mmφ, a peripheral speed of 90 m / sec can be obtained at a rotation speed of 3,500 rpm. Therefore, it is not necessary to rotate the stock solution supply pipe shaft 16 at an extremely high speed,
Spraying is possible at low speed (2P motor rotation speed), and at the same time the weight of the sprayer body is reduced and the required horsepower of the motor that drives the sprayer to rotate is only about 1/3 that of the conventional structure. Is. Further, it has a feature that the rotational noise during operation also decreases as the rotational speed decreases.

According to the above configuration, the spray angle of the liquid droplets can be arbitrarily and easily changed by changing the mounting angle of the propeller blades 22, so that the diameter of the drying chamber 2 can be designed to be small and the drying device The whole can be miniaturized.

As shown in FIG. 4, a spray nozzle is attached to the tip of the propeller blade 22.
An injection propeller blade 22 is provided by attaching a nozzle member 28 having 30 and pressurizing the liquid at a pressure of 5 to 10 kg / cmG by an external pump (not shown) communicating with the raw liquid supply port 26 of the rotary pipe joint 25. The stock solution is temporarily sprayed from the nozzle member 28 provided at the tip of the nozzle, and the liquid particles of the pressurized spray are ejected in a linear trajectory. However, since the propeller blades 22 are rotating, the flight trajectory of the liquid particles ejected from the nozzle member 28 turns in a curved shape, and the flight distance until it impinges on the wall of the drying chamber 2 becomes long. Even if the diameter of the drying chamber 2 is reduced, a sufficient flight distance required for heat exchange can be obtained.

Further, in the above configuration, the drying air in the inner space of the drying chamber 2 is vigorously agitated and vibrated by the rotation of a large number of jet propeller blades 22, so that the liquid particles scattered in the form of mist and the hot air are sufficiently contacted (heat exchange). Therefore, the thermal efficiency of the device can be improved.

[Advantages of the Invention] As described above, according to the configuration of the centrifugal sprayer for a spray dryer according to the present invention, there are advantages that the prior art cannot achieve at all, (1) Supply to the spray rotating disk The dropping position of the undiluted solution became an ideal position for spraying, the installation of the liquid feeding pipe was unnecessary, the structure was simplified and the handling became convenient.

(2) Due to the structure of the injection propeller blades, which replaces the conventional rotating disk, the rotation speed is 1/3 lower than that of the conventional structure, so the driving power can be reduced and the noise generated can be reduced.

(3) Moreover, since the injection angle can be arbitrarily narrowed by the structure of the injection propeller blade, the diameter of the drying chamber can be reduced to about 1/2 of that of the conventional one.

(4) Since the double spray method is a combination of pressure spray and rotary spray, the objective can be achieved by low-pressure supply of the stock solution and low-speed rotation of the stock solution supply pipe shaft.

(5) The vigorous agitation of the drying air continues due to the rotation of the propeller blades provided on the rotating disk, which causes an increase in the heat exchange area due to the contact between the mist-like droplets and the hot air, thus increasing the thermal efficiency. Can be greatly improved.

Was obtained, and the effect after the present invention was carried out was extremely large.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a centrifugal sprayer for a spray dryer according to the present invention, FIG. 2 is a bottom view of the same, and FIG. 3 is a schematic sectional view showing a state of being installed in the dryer. FIG. 4 is a cross-sectional view of a propeller blade end portion showing a state in which a spray nozzle is provided. 1 ... Centrifugal sprayer, 2 ... Drying chamber, 5 ... Hot air jetting device, 6 ... Gas supply port, 7 ... Exhaust port, 8 ... Exhaust pipe, 12 ... Main body frame, 14, 15 ... Bearing, 16 ...
... undiluted solution supply pipe shaft, 21 ... propeller blade mounting seat, 22 ... injection propeller blade, 25 ... rotating pipe joint, 26 ... undiluted solution supply port, 27 ... undiluted solution supply path, 28 ... nozzle member.

Claims (2)

[Claims] 1. A centrifugal sprayer for a spray dryer for spraying and drying an undiluted solution to be dried in a dry air atmosphere, wherein a hollow shaft which is rotatable by an external rotation drive mechanism is provided axially, and a lower end of the hollow shaft. A plurality of thin pipe-shaped injection propeller blades are radially and evenly projected in a downward angle direction of 30 to 60 degrees from the horizontal position with respect to the propeller blade mounting seat fixedly installed in A centrifugal sprayer for a spray dryer, wherein a stock solution supply pipe is formed through a rotary pipe joint provided at an upper end of the stock solution supply pipe shaft. 2. A spray nozzle member is provided at each injection propeller blade end projecting from the propeller blade mounting seat.
Centrifugal sprayer for the spray dryer described.