Electromagnetic Drive Feeders

Applications
Electromagnetic drive feeders and conveyors are used for applications where a controlled and instantaneously variable feed rate is required. They are particularly suitable for frequent and rapid stop / start operation as the run up and stop time is virtually instantaneous. This makes them an ideal choice for applications such as high speed and high accuracy batch weighing, bulk filling and weighing, charging, discharging and controlled transfer.

Twin Motor Drive Units

Applications
Twin motor drive feeders and conveyor units are ideal for high capacity feeding and conveying applications where the throughput rate is fixed or infrequent adjustment is required. They are used in many industries such as steel making, mining, quarrying, foundries, food processing and chemical industry for the feeding and transfer of bulk materials. Unlike other systems, they are simple to install and do not require skilled tuning on site. Although the maximum single unit length is 6m, multiple units can be mounted in series with minimal or no height loss to achieve greater conveying lengths.

General Feeder and Conveyor Construction

The main feeder structure consists of a weld fabricated conveying trough, which can be supplied as a trapezoidal, rectangular or tubular assembly, and drive mounting assembly onto which the drive unit is mounted. The drive and drive assembly can be mounted below or above the trough. The trough and associated structure are normally manufactured in either carbon steel, stainless steel or a combination of both. These materials are adequate for the majority of applications, but the conveying troughs can also be manufactured from other materials such as abrasion resistant steel, polypropylene, etc. Also, liners and coatings can also be incorporated into the trough to help eliminate or minimise various problems such as: expendable liners for highly abrasive applications; flexible liners for light products that have a tendency to adhere or compact; energy absorption liners like laminated rubber and steel, polypropylene, rubber and polyurethane which minimise noise generation caused by the impacting of the product on the trough during conveying. Tubular feeders and conveyors are ideal for applications where dust emissions, atmospheric pollution or product contamination need to be prevented. The conveying tubes are crevice free and can be fitted with either bolted or quick release dust tight end plates. Bolted or quick release dust tight covers can also be fitted to trapezoidal or rectangular section troughs on which both the inlet cover and the outlet of the conveying trough can be fitted with either discharge spigots or bolting flanges for flexible sleeves.
 
All equipment can be manufactured in accordance with the hygiene and legislative requirements of the food and pharmaceutical industries. A range of equipment finishes are available for both product contact and non contact surfaces which include spraying, powder coating, polishing and bead blasting.

Drive Systems

Electromagnetic Drive Units

The range of electromagnetic vibrators used are essentially closed two mass oscillation systems tuned to operate in the subcritical frequency zone.

The oscillation frequency of the drive unit is selected to suit the duty of the vibrating feeder or conveyor, with particular reference to the  handling characteristics of the material being conveyed. For example 50Hz drive units are generally used when feeding course grained bulk materials with densities of up to 1.6 t/m3 whilst 25Hz drive units are used for bulk materials such as powders having densities below 1.0 t/m3.
33Hz drives are used where a high performance combination of the above is required.

Electromagnetic drive units also offer the following advantages:-

• Long service life
• Low power consumption
• Low noise level
• Low maintenance with no routine maintenance required
• No loss of performance with high bulk loadings
• Units available for use in areas where potentially explosive atmospheres exist.

Electromagnetic Drive Control Units

Electromagnetic drive feeders are connected to an a.c. electrical supply by means of a power controller which incorporates a variable amplitude control facility for regulation of the feeder output. There are a wide range of control units and control functions available for the complete range of feeders, from simple on/off manually operated units to voltage regulated systems with inbuilt facilities for accepting a range of control  signals for automatic regulation of  feeder output.

all the power controllers can be supplied to IP00 or in an enclosure to suit a specific specification, and are available for all the recognised voltage and frequency power supplies.

Twin Motor Drives

In the case of twin vibrator motor drives, the feeder or conveyor structure together with the two vibrator motors form the principle mass of a single mass oscillation system with a single degree of freedom. when the eccentric masses of the vibrator motors are contra-rotated forced vibrations are set up in the system resulting in uni-directional displacement of the trough which, together with the angular displacement of this motion to the conveying plane, produces directional movement of the material.

Vibrator motors are available for connection to most recognised mains supply voltages and offer nominal oscillation frequencies of 50Hz, 25Hz, 16Hz and 12Hz when connected to a 50Hz electrical supply and 60Hz, 30Hz and 20Hz when connected to a 60Hz electrical supply. The choice of oscillation frequency is normally determined by the size of the feeder or conveyor, the product being conveyed and the volumetric output required.

Vibrator  motors offer the following advantages:-

• Robust construction
• High output force in relation to weight
• Easy to use and connect
• Low maintenance, require practically no servicing
• Units available for use where potentially explosive atmospheres exist.

Twin Motor Drive Control Units

The vibrator motors on twin motor drive feeders and conveyors must be connected to a power supply by means of a two motor starter unit. This connects both motors direct to the mains supply simultaneously and provides interlocked overload and single phase protection for each unit. Where multiple units are used as a continuous conveying system, a common control panel with sequential starting and stopping can be provided. When a twin motor drive feeder is switched off with standard controls a temporary increase in amplitude occurs as the motors slow down and pass through the resonant frequency of the suspension mounts, but this can be minimised by incorporating d.c. injection braking

Inverter based controls can also be supplied which provide limited feed rate control within the  range of 20% to 100% of the maximum volumetric output of the feeder. Control units are available for connection to most recognised mains electrical supplies and can be supplied in IP00 form or in an enclosure of construction and protection to suit the customers specific needs.

Suspension Mounts

These can take one of four forms, bonded rubber mounts, hollow rubber mounts, helical coil compression springs or helical coil tension springs. The type of mount is selected to suit the requirements of the installation and to provide a minimum isolation efficiency of 95%.

Throughputs

Data sheets are available on request for standard feeder and conveyor units which show the maximum volumetric feed rates obtainable for each unit when handling dry, free flowing granular material.
It should be noted that the specified volumetric feed rates can be reduced when handling materials with bulk densities greater than 1.6 t/m3 and less than 1.0 t/m3, also materials with a high moisture content or a high percentage of fines.

Specials

In addition to our standard range equipment we can design and manufacture equipment to suit customers specific requirements

Application

The range of Hopper Feeders has been designed as a self discharging bulk storage hopper capable of storing and then discharging components or materials in a controllable, continuous stream. Particularly suitable for components or products that tangle or do not feed well from static hoppers, the hopper feeder eliminates many of the interruptions in production that can occur with more conventional systems.

Construction

Hopper Feeders are available in five basic sizes, although specials can be manufactured for specific applications.

The Hopper Feeder consists of a weld fabricated structure in either carbon steel or stainless steel. when produced in carbon steel the internal surfaces are lined with an abrasion resistant and noise deadening polyurethane. When produced in stainless steel, a hygienic construction is used making the unit suitable for use in the food and pharmaceutical industries. The drive unit is bolted to the underside of the structure, the whole unit being mounted on four suspension mounts rated to give a minimum isolation efficiency of 95% when loaded. support frameworks can be supplied to suit customers individual requirements.

Mode of Operation

Hopper Feeders are essentially closed two mass oscillation systems, sub-critically tuned. The vibratory drive unit and structure are designed to give an asymmetric displacement of the conveying plane which results in a progressively increasing product velocity towards the discharge  end of the hopper. This motion prevents mass flow and creates an untangling and thinning out effect on the material / parts being handled, reducing them to a manageable quantity. Special low frequency, high amplitude units are available for products which are particularly difficult to handle.

Control Units

Electromagnetic drive feeders are connected to an a.c. electrical supply by means of a power controller which incorporates a variable amplitude control facility for regulation of the feeder output. There are a wide range of control units and control functions available for the complete range of feeders, from simple on/off manually operated units to voltage regulated systems with inbuilt facilities for accepting a range of control  signals for automatic regulation of  feeder output.

all the power controllers can be supplied to IP00 or in an enclosure to suit a specific specification, and are available for all the recognised voltage and frequency power supplies.