RU2315931C1 - Pneumatic dryer with a double-wound spiral - Google Patents

Abstract

FIELD: the invention refers to drying technique of dispersed materials and may be used in microbiological, food, chemical and other fields of industry.

SUBSTANCE: the result is achieved due to the fact that in the pneumatic dryer with a double-wound spiral having a spiral channel, a body hermetically closed with a lid, inlet and outlet sockets, the spiral channel is fulfilled in the shape of a plane double-wound spiral of a rectangular section located in a vertical plane and formed by spiral tapes, the body and the lid with an elastic washer. At that the spiral tapes are winded up concentrically in such a way that form in the center a fluent S-shaped passage and on the body there is a fixed vibrator whose optimal work parameters are the level of vibration in the diapason of 70 85 db, a vibration frequency in the range of 31,5 125 Hz, expose time of 5 seconds with an interval of 30 seconds.

EFFECT: increases efficiency of the dryer.

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Description

The invention relates to techniques for drying dispersed materials and can be used in microbiological, food, chemical and other industries.

The closest technical solution to the claimed object is a pneumatic dryer combined spiral-vortex for AS USSR No. 553424, F26В 17/10, 1975, containing a spiral channel, top and bottom hermetically sealed with a lid and a bottom, respectively, with the formation of a vortex chamber, inlet and outlet pipes (prototype).

The disadvantage of the prototype is the relatively low productivity of drying the final product.

The technical result is an increase in drying performance.

This is achieved by the fact that in a pneumatic dryer with a bifilar spiral containing a spiral channel hermetically sealed by the housing and the cover, an inlet and outlet pipe, the spiral channel is made in the form of a flat rectangular bifilar spiral located in a vertical plane and is formed by spiral ribbons, the housing and the cover with an elastic gasket, and the spiral sheets are wound concentrically so that they form a smooth S-shaped transition in the center, and a vibrator is mounted on the body, the optimal operating parameters of which are yayutsya vibration level in the range of 70 ... 85 dB, the oscillation frequency in the range 31.5 ... 125 Hz, the exposure time is 5 seconds at intervals of 30 seconds.

Figure 1 presents a General view of a pneumatic dryer, figure 2 - section aa of figure 1.

A pneumatic dryer with a bifilar spiral contains a drying path, which is made in the form of a flat bifilar spiral 1 located in a vertical plane. The drying spiral channel 1 of rectangular cross section is formed by spiral ribbons 2 and 3, the housing 5 and the cover 6 with an elastic gasket 7. The spiral sheets are wound concentrically so that they form a smooth S-shaped transition 4 in the center.

A vibrator (not shown) is fixed on the housing 5 to improve the hydrodynamics of the process, removing the wet or unprepared product adhering to the spiral channel 1 walls. The vibrator can also be mounted on the cover 6 or directly on the wall of the spiral channel 1 (not shown). The optimal parameters for vibration processing are the vibration level in the range of 70 ... 85 dB, the oscillation frequency in the range of 31.5 ... 125 Hz, the exposure time of 5 seconds with an interval of 30 seconds.

When drying dispersed materials with a long second period, it is advisable to carry out drying in milder modes after removing free moisture. To ensure such regimes, it is necessary to observe the optimal ratios of the design parameters of the dryer, namely: the ratio of the diameter D _{1 of the} separation chamber to the diameter D _{2 of the} vortex chamber lies in the optimal range of values: D ₁ / D ₂ = 0.57 ... 0.84; the ratio of the diameter D _{1 of the} separation chamber to the diameter D _{3 of the} exhaust pipe lies in the optimal range of values: D ₁ / D ₃ = 1.6 ... 1.8; the ratio of the height H of the spiral channel to its width B lies in the optimal range of values: H / B = 1.5 ... 4.0; the ratio of the width B of the spiral channel to its length L lies in the optimal range of values: B / L = 3.3 · 10 ^-3 ... 7.2 · 10 ^-3 ; the ratio of the diameter D _{H of the} apparatus to its height Hn lies in the optimal range of values: D _H / _Hn = 0.58...0.82.

A pneumatic dryer with a bifilar spiral works as follows.

The gas suspension is transported from the inlet to the outlet and is dried, passing the path from the periphery to the center, and then from the center to the periphery. A change in the curvature of the particle trajectory creates conditions for the non-stationary nature of the hydrodynamic regime and heat and mass transfer under the condition of ideal phase displacement, i.e. at the maximum driving force of the drying process. Bifilar winding of channel 1 provides heat recovery along the length of the drying channel and reduction of heat loss to the environment.

The initial turns of channel 1 are in contact with the weekend, so the final stage of the convective drying process proceeds under conditions of additional heat supply through a spiral partition. Due to the redistribution of heat, the drying process will take place with a decrease in the enthalpy of the drying agent at the beginning of the process and an increase at the end. Thus, the driving force tends to maintain a constant value throughout the drying process, and to complete the drying process does not require the supply of fresh coolant or a second degree of drying.

Bifilar placement of the spiral channel allows you to maintain a high process intensity at an air flow rate of 30 ... 35 thousand m ³ / h and above, which ensures the use of dryers of this type for medium and large-capacity industries, where they can give a great economic effect. The hydraulic resistance of these dryers is small and amounts to 1.0 ... 2.5 kPa with a spiral channel length of 10 to 25 m.

The proposed air dryer with a bifilar channel can be used for drying materials with free moisture, in particular for the production of chemical, food, agricultural and other industries.

Claims (1)

A pneumatic dryer with a bifilar spiral, comprising a spiral channel formed by spiral tapes and hermetically closed by a body and a cover with an elastic gasket, an inlet and an outlet nozzle, characterized in that the spiral channel is made in the form of a flat bifilar spiral of rectangular cross-section located in a vertical plane, moreover, spiral tapes they are wound concentrically so that they form a smooth S-shaped transition in the center, and a vibrator is mounted on the body, the optimal operation parameters of which are: vibration level ii 70-85 dB in the range of oscillation frequency in the range 31,5-125 Hz, exposure time 5 seconds at intervals of 30 seconds.

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