Glossary of Terms

Glossary of Terms used with Acrison's Bulk Solids Handling Equipment

AC Motor - An AC Motor is an electric motor driven by alternating current. An AC Motor may be operated at a constant speed, without variable speed control, or furnished with a variable frequency controller for variable speed control. Variable speed AC Motors generally provide a 10:1 drive turndown ratio.

Adhesive - This a characteristic of a dry solid material that causes it to adhere onto various surfaces. If not properly addressed, such a characteristic can be detrimental to a dry solids metering mechanism.

Aerated - This is a condition whereby a dry solid material entraps air, frequently causing the material to act as a fluid in its behavior, often resulting in uncontrollable flushing through a metering mechanism and/or its supply hopper. Aeration is usually caused by product having been conveyed pneumatically, usually into a storage hopper, or the use of an air or gas purging system in the product containment zone.

Agglomerated - This is a characteristic of a dry solid material that results in the formation of lumps.

Agitator - An Agitator is a device designed to promote downward flow (discharge) of product and to assist in filling the metering auger of various Acrison metering mechanisms. Depending on the model metering mechanism, one or more Agitator(s) may operate completely independently of the metering auger, or may operate proportionally to the speed of the metering auger through a gear mechanism. Different Agitator types and designs are available, the selection of which is determined by the physical handling characteristics of the product or products involved.

Bin Discharger - An Acrison Bin Discharger is a device specifically designed to mount onto the bottom of a storage hopper to promote the reliable discharge of product from within by means of defined, mechanically-induced, internal agitation. It is especially effective when used with dry solid products that are considered "very difficult" to handle. The housing of the Bin Discharger is designed without convergence (totally unlike conical, pyramidal or wedge type bin bottom designs) which often prove detrimental to product flow.

Bridging/Rat-Holing - This is a condition whereby a dry solid material arches or bridges across a storage hopper resulting in sporadic flow or a complete cessation of flow from the hopper. A dry solids storage hopper must be properly designed to ensure adequate discharge of material at all times.

Compacted - This is a characteristic of a dry solid material to compress and/or harden, usually due to head-load or another type of pressure. Generally, pressure sensitive or cohesive materials will compact. Also, very fine materials often exhibit this characteristic.

Conditioning Auger/Agitator - Certain model Acrison dry solids feeders include double or triple Conditioning Auger/Agitator metering mechanisms. (Acrison's Double Concentric Auger metering mechanism is described under Intromitter.) In all cases, these Conditioning Auger/Agitator mechanisms have been specifically designed for optimum dry solids metering/handling performance.

Conditioning Augers/Agitators "condition" the dry solid material being handled by first ensuring that the metering auger is completely and effectively "filled" with product of constant density and secondly, to simultaneously agitate the product within and surrounding the Conditioning Auger(s)/Agitator(s) to additionally ensure proper flow of material into the metering auger.

Conditioning Chamber - The Conditioning Chamber houses the feeder's metering mechanism. An integral supply hopper typically attaches directly to the top flange of the Conditioning Chamber. The Conditioning Chamber is also called a feed chamber and is constructed of steel.

DC Motor - A DC Motor is an electric motor driven by direct current. Variable Speed DC Motors can produce either a 30:1 or 50:1 drive turndown ratio.

Discharge Cylinder - The Discharge Cylinder is the discharge spout of an Acrison dry solids metering mechanism, within which the metering auger rotates, and through which the metering auger discharges product.

Dissimilar Speed Gearbox - Acrison's Dissimilar Speed Gearboxes house the dual or triple auger/agitator gearing mechanisms that provide the desired ratio of speed differential between the smaller metering auger and the larger agitator or conditioning auger (the Intromitter), or between the smaller metering auger and the larger conditioning auger(s)/agitator(s).

Double Concentric Drive Mechanism - This is the gearing mechanism that drives Acrison's Double Concentric Auger Metering Mechanism.

Drive Motor - The Drive motor powers the feeder's metering mechanism. The Drive Motor is normally AC (alternating current) and variable speed. A DC drive motor is available as an option and may also be variable speed.

End Bearing Support - This is an optional support arrangement for the metering auger installed on the end of the discharge cylinder.

External Feed Rate Input Setting - This is a means for remotely setting the feed rate of a metering mechanism from an external source (usually a voltage, current or digital signal).

Extruding - This is a characteristic whereby product discharging out of a feeder's discharge cylinder is compressed, typically discharging in the form of a plugged stream of material.

Feed Chamber - The Feed Chamber of an Acrison dry solids metering mechanism houses Acrison's various single or multiple auger/agitator metering mechanisms (also called a feed trough).

Feed Chamber Vibration - Vibration is applied to the feed chamber of certain model Acrison metering mechanisms for the purpose of ensuring that the metering auger is efficiently and effectively "filled" with product.

Feeder Hopper - This is a dry solids supply hopper (or storage hopper), for product supply which is mounted above the feeder's metering mechanism. The Feeder Hopper may be integral with the metering mechanism, bolted to it, or flexibly connected to it.

Feeder Motor - This is analogous to drive motor; powers the metering mechanism of a feeder. Usually, the Feeder Motor is part of a variable speed DC drive system.

Feeder (or Feed) Trough - A Feeder Trough is basically synonymous to a feed chamber, although a trough is usually shaped more like a "V," whereas most feed chambers are shaped like a "U." Acrison "V" shaped feed troughs usually house a single metering auger at its bottom.

Feed Range Capability - This is the output feed range capable of being produced by the selected metering mechanism in conjunction with the size of its metering auger.

Flushes (or Flushing) - Typically, this is a condition whereby a dry solid material behaves as a "fluid," usually because the material is aerated. Such a condition may cause the material to pass uncontrollably through a metering mechanism and/or its supply hopper.

Gear-reducer - This is the mechanism that reduces the motor speed to the desired speed for driving the metering mechanism. The Gear-reducer is available with one of several ratios, determined by product characteristics and application parameters, thereby establishing the maximum speed of the metering auger and its maximum feed rate output capacity. The feeder's drive motor flange-attaches directly to the Gear-reducer, and the Gear-reducer flange-attaches directly to the feeder's gearbox or seal housing.

Helical (Metering) Auger - A Helical Auger is an open center coil or spiral, for the purpose of conveying and metering dry solid ingredients out of a dry solids feeder.

Hopper Vibration - Vibration is imparted to the supply hopper of a dry solids metering mechanism to induce reliable flow of material into the feed chamber (or feed trough) of the metering mechanism.

Intromitter (Conditioning Auger) - Certain model Acrison volumetric feeders include Acrison's unique Double Concentric Auger Metering Mechanism, with the larger of the Double Augers called the Intromitter (or Conditioning Auger). The Intromitter is normally a helically wound device but can also be provided in other configurations as well, based on the handling characteristics of the product(s) being handled.

In operation, the Conditioning Auger produces a bidirectional, opposing sliding movement of product within the confines of the Double Concentric Augers. This opposing movement is produced by the speed differential between the Intromitter and the slower rotating metering auger. This movement gently conditions the material to a very consistent density while simultaneously, fills the smaller, centrally located metering auger from a full 360 degrees.

Mechanical Drive - This is a variable speed drive (mechanically operated) used to power the feeder's metering mechanism (i.e., in lieu of a variable speed SCR controlled DC drive which is electronic).

Metering Auger - A Metering Auger is a spiral type conveying device, centrally situated inside the feed chamber or feed trough of the dry solids metering mechanism, to volumetrically displace product out of the feeder through the discharge cylinder. Various sizes, types and designs are available, the selection of which is determined by the feed rate and the physical characteristics of the product. Rotation of the metering auger produces a specific volume of product discharge through the discharge cylinder for each revolution.

Metering Mechanism - A Metering Mechanism is a device specifically designed to meter a dry solid ingredient. Various designs are available, the selection of which is determined by the feed rate requirements and product handling characteristics.

Moisture Content - This is the amount of a liquid (i.e., water, oil, solvent, etc.) that is contained within a dry solid material, usually expressed in percent.

Particle Size - Particle size refers to the size of the individual particles that comprise a dry solid material, usually expressed in "mesh" sizes, sieve analysis or in some other dimensional form.

Product Bulk Density - Bulk Density is the weight of a dry solid material, typically expressed in pounds per cubic foot.

Refill Device - A refill device is the mechanism used to refill the supply hopper of a "weight-loss" weigh feeder. In most dry solids metering applications, the refill device is a storage hopper equipped with a quick acting, automatically operated slide gate; however, it can be other mechanisms as well, provided such mechanisms meet all of the criteria necessary for proper weigh feeder operation.

SCR Controller - An SCR Controller is a variable speed electronic device that precisely regulates the speed of a DC motor to a selected speed setting. Normally, SCR Controllers provide either a 30:1 or 50:1 turndown ratio depending upon the selected model controller.

Seal - This is the means used to prohibit material from escaping from around rotating shafts either entering or exiting the metering mechanism of a dry solids feeder.

Solid Flight (Metering) Auger - A Solid Flight Auger is a closed section type spiral, normally constructed of a flat metal winding with a center shaft, for the purpose of conveying dry solid ingredients out of a dry solids feeder. Various configurations and designs are available to satisfy the requirements of specific applications.

Supply Hopper - A Supply Hopper is the container used to store a dry solid material typically for use by a dry solids feeder. A Supply Hopper may be mounted integral to a metering mechanism (feeder), bolted to it, or may be mounted separately, usually flexibly connected to the metering mechanism.

Surface Finish and/or Coating - Metering mechanisms, or components thereof, may be furnished with various types of finishes or coatings to aid in resisting product adhesion, component wear and/or corrosion. In particular, a number of specialty coatings (and laminations) are used to reduce or eliminate product adhesion onto critical components.

Tachometer - A digital Tachometer provides very precise speed sensing to assist in producing the highest possible degree of DC motor speed regulation, linearity and repeatability. Acrison SCR controllers that provide a 50:1 drive turndown ratio, or those used in conjunction with Acrison weigh feeders, utilize a Tachometer for speed feedback data. The Tachometer is either directly connected to the output shaft of the DC motor, through a specially designed gear-reducer, or senses the speed of the motor by means of a magnetic sensor.

Torque Limiter Coupling - This is a device mounted between the feeder's gear-reducer and input shaft to provide adjustable overload protection of the drive components.

Variable Frequency (AC) Controller - A Variable Frequency Controller is an electronic device that varies the speed of an AC motor to a selected speed setting. An AC Variable Frequency Controller normally provides a 10:1 turndown ratio.

Variable Speed Controller - This is a controller specifically designed to precisely regulate the speed of the feeder's drive motor to a selected speed setting. Normally, Variable Speed Controllers may be either AC or DC and provide either a 10:1, 30:1 or 50:1 turndown ratio depending upon the type and model controller.

Vibrator Controller - The Vibrator Controller is a device used to control the intensity of force produced by a variable speed (or variable frequency) vibrator.

Volumetric Feeder - A Volumetric Feeder is a device specifically designed to accurately meter dry solid materials by volume. A true volumetric feeder must include a means to measure by volume, such as a rotating auger.

Weigh Feeder - A Weigh Feeder is a device specifically designed to meter various products by weight control. A scale is an integral component of a weigh feeder.

Weighing Mechanism (Scale) - An Acrison Weighing Mechanism is a highly precise scale consisting of a lever network which physically "moves" as weight is added to or subtracted from it. This movement is measured by a digital displacement sensor, converting displacement into weight units having a discrete resolution of one part in 1,048,576.

"Weight-Loss-Differential" - This is the "generic" term for weigh feeders that operate on a loss-of-weight basis. A properly designed Weight-Loss weigh feeder is capable of producing optimum weigh feeding performance for both dry solids and liquid ingredients. A Weight-Loss weigh feeder only weighs the amount of product fed and modulates the feed output of its integral metering mechanism in comparison to a feed rate set point. A Weight-Loss type weigh feeder does not use a zero reference for calibration, as do weigh belt weigh feeders for example, and therefore, an optimum level of feed accuracy can be achieved.