Rotary Valve Types and Selection

Rotary valve belongs to star-like material feeding and discharge devices. The body usually consists of rotor wheel, shell, seals, gear box and electric motor.

l  Structure Types

According to mediae’s characteristics, application and use conditions, several structure installation types are available for choice.

Bearing-built-in Direct Connection Type:  A gear box is connected with main body directly. The design is compact and transmission efficiency is high. It is applicable for low temperature mediae and large-grain-size mediae.

Bearing-outboard Direct Connection Type:  A bearing is placed at the outer end of the end cover and keep some distance from material or media. It is applicable for high temperature mediae, easy leakage materials (e.g. ultrafine powder). The bearing has a long use life span.

Bearing-outboard Side Chain Type:  A sprocket is used for transmission. The gear box motor is sided and connected with the main body with a connection plate. It is featured with high transmission ratio, durability and easy maintenance and repair.

l  Rotor Wheel Types

According to different media’ characteristics, several rotor wheel types are available for choice.

                   (1)             (2)           (3)            (4)

   (1)：Open type rotor wheel

(2)：Inserted disc rotor wheel

(3)：Close type rotor wheel

(4)：Anti-adhesive rotor wheel

According to different pressure, the blade quantity is 6 pieces, 8 pieces, 10 pieces or 12 pieces for choice.

l  Construction Material

The main body can be made of stainless steel, carbon steel, cast iron, cast steel, ductile cast iron, cast aluminium, cast copper and etc.

l  Driven Power

According to different requirements, there are ordinary motor, freqency inverter motor and explosion-proof motor for choice.

l  Application Field

A rotary valve is widely used in petrochemicals, electric power, metallurgy, mine, grain and oil, foodstuff, fodder, medicine, building material, tobacco, wood, casting, textile, drying, dust-proof and other industries.

When it is used at the bottom of a feed bin, the material fall down by gravity and fill in the space between blades of the rotor wheel of the rotary valve. Then it rotates together with the blades, finally falls down at the lower position. In this way, quantitative and continuous material discharge can be realized.

In the positive pressure and negative pressure pneumatic conveying system, a rotary valve can feed material evenly and continuously to a transport pipe to ensure stable flow rate of solid and gas. At the same time, it can cut gas from the top side to lower side of the discharger, therefore it can lock gas and make pneumatic conveying can be working smoothly.

l  Output (discharge output) G Calculation Formula

G=0.06V.N.Y.R.K (ton/hr)

V: volume (L/r)     N: rotary speed (r/min.)

Y: volume efficiency (granule material value 0.8, powder material 0.5-0.6)

R: bulk density (ton/m³)

K: correction ratio (usually value 0.7-0.8)

l  Model Selection

In order to select a suitable model for you, please inform us:

1.    Construction material --- cast iron, carbon steel, stainless steel, aluminium, copper or alloy.

2.    Conveyed material’s property—grain size, moisture content, bulk density, angle of test, and ect.

3.    Application--- positive pressure conveying, negative pressure conveying and pressure difference between top and bottom blades.

4.    Conveying capacity---- discharge output per hour, is a quantitative conveying  needed?

5.    Speed ratio of a gear box, the protection grade of electric motor. Is an adjustable speed or inverted frequency needed?

6.    Installation dimensions.

Rotary Feeder Introduction

Rotary Feeder

Rotary feeders, also known as rotary airlocks or rotary valves, are commonly used in industrial and agricultural applications as a component in a bulk or specialty material handling system. Rotary feeders are primarily used for discharge of bulk solid material from hoppers/bins, receivers, and cyclones into a pressure or vacuum-driven pneumatic conveying system. Components of a rotary feeder include a rotor shaft, housing, head plates, and packing seals and bearings. Rotors have large vanes cast or welded on and are typically driven by small internal combustion engines or electric motors.

Rotary airlock feeders have wide application in industry wherever dry free-flowing powders, granules, crystals, or pellets are used. Typical materials include: cement, ore, sugar, minerals, grains, plastics, dust, fly ash, flour, gypsum, lime, coffee, cereals, pharmaceuticals, etc.

Industries requiring this type include cement, asphalt, chemical, mining, plastics, food, etc.

Rotary feeders are ideal for pollution control applications in wood, grain, food, textile, paper, tobacco, rubber, and paint industries, the Standard Series works beneath dust collectors and cyclone separators even with high temperatures and different pressure differentials.

Rotary valves are available with square or round inlet and outlet flanges. Housing can be fabricated out of sheet material or cast. Common materials are cast iron, carbon steel, 304 SS, 316 SS, and other materials. Rotary airlock feeders are often available in standard and heavy duty models, the difference being the head plate and bearing configuration. Heavy duty models use an outboard bearing in which the bearings are moved out away from the head plate. Housing inlet and discharge configurations are termed drop-thru or side entry. Different wear protections are available such as hard chrome or ceramic plating on the inner housing surfaces. Grease and air purge fittings are often provided to prevent contaminants from entering the packing seals.

·         Rotary airlock

The basic use of the rotary airlock feeder is as an airlock transition point, sealing pressurized systems against loss of air or gas while maintaining a flow of material between components with different pressure and suitable for air lock applications ranging from gravity discharge of filters, rotary valves, cyclone dust collectors, and rotary airlock storage devices to precision feeders for dilute phase and continuous dense phase pneumatic convey systems.

·         Rotary valve

Rotary airlock feeders/ rotary airlock valves are used in pneumatic conveying systems, dust control equipment, and as volumetric feed-controls.

·         Volumetric feeder

Rotary airlock valves are also widely used as volumetric feeders for metering materials at precise flow rates from bins, hoppers, or silos onto conveying or processing systems.

Rotary airlock feeders

Drop through rotary airlock feeders are designed for rugged applications that require an outboard bearing style unit where contamination and /or an abrasive product cannot be handled with an inboard bearing style. The outboard bearing feeders is engineered for use in high pressure pneumatic conveying systems, with high temperatures where more of an effective seal is required due to high or excessive wear that is experienced with a simple dust collector.

Blow-thru rotary airlock feeder

The blow-thru rotary airlock feeder is ideal for pneumatic conveying applications in food, grain, chemical, milling, baking, plastics and pharmaceutical industries. The blow-thru airlocks feature a low profile with large capacity. High pressure differentials integral mounting feet, and retrofit competitive units. The blow-thru valves are available with 10-vane open-end rotor; outboard bearings and replaceable shaft seals.

Easy clean rotary feeder

The easy-clean series rotary feeders can be fast and simply disassembled, thoroughly quick cleaned, sanitized and inspected or maintenance in a minimum amount of time without the use of tools or removal from service, thereby reducing downtime and increasing system production. Reassembly without tools is accomplished in minutes. Internal clearances are automatically re-established every time.

The Clean-in-place rotary feeder is a special purpose valve designed for where cross-contamination is a major concern and lengthy shut-downs for clean-out are cost-prohibitive, suited for Dairy, Pharmaceutical industries, Food, Baking, Chemical, Plastics, Paint, and Powder Coating plants.

It is ideal for batch mixing systems such as those handling different colored resins which demand regular cleaning between cycles.