Angled front view of a small and large PosiPortion™ feeder from Hapman

Achieve your product dosing goals with our custom-engineered material handling equipment and systems

Hapman’s full line of gravimetric and volumetric screw feeders – including the PosiPortion™ Feeder, Screw Feeder, and Vac-Feeder – is engineered for industrial processing of dry material in either continuous or batching operations.



Gravimetric & Volumetric Feeders

Precisely and Consistently Feed a Wide Range of Materials

PosiPortion Gravimetric & Volumetric Feeders | Hapman.com
Larger angled front view of large and small PosiPortion™ feeders from Hapman
  • Flexible-wall hopper provides flow performance for materials that tend to bridge 
  • External paddle agitators maintain material quality without degradation, segregation or agglomeration.
  • Disassembles and cleans easily with quick coupled components.  Toggles clamps and half-turn fasteners make this the quickest feeder on the market to disassemble.
  • Steel reinforcement molded into the flexible hopper enables the hopper to retain its shape, even when removed from the frame with material.
  • Structural tubing frame provides strength and stability.
  • Open bottom chassis minimizes stray product from accumulating in the frame.
  • Quick-change screws.  Swapping screws with an empty hopper takes less than one minute.


Economical, Robust Feeders

Designed to Effectively Handle a full range of products from Dry Powders to Thick Paste

Hapman Screw Feeders | Hapman.com
  • Economical, robust feeder.
  • Handles wide range of materials
  • Heavy-duty design that will operate in harsh conditions and deliver material consistently regardless of material type.
  • Start under heavy load.
  • Multiple types of internal agitation available to maximize performance.

Screw Feeder Specifications

Standard Models and Theoretical Capacities

Standard models and theoretical capacities | Hapman.com

Nominal Feeder Frame Dimensions

Nominal feeder frame dimensions | Hapman.com

PosiPortion Feeder Features

PosiPortion Gravimetric & Volumetric Feeders | Hapman.com
PosiPortion Gravimetric & Volumetric Feeders | Hapman.com


  • Handle and store hopper easily. Steel reinforcement molded into the flexible hopper flange enables the hopper to retain its shape and capacity when removed; even when full of product.
  • Screw is quick-coupled, allowing the hopper to be removed in seconds. Unique design prevents decoupling when torque is applied.
  • Get the strength and stability of structural tube-frame construction with the ability to support large hoppers or ancillary equipment.
  • Optimize product flow with external paddle agitators that reduce bridging, limit material contact surfaces, reduce opportunity for contamination, and simplify cleaning.

PosiPortion Feeder Options

PosiPortion Gravimetric & Volumetric Feeders | Hapman.com
PosiPortion Gravimetric & Volumetric Feeders | Hapman.com
PosiPortion Gravimetric & Volumetric Feeders | Hapman.com
PosiPortion Gravimetric & Volumetric Feeders | Hapman.com

  • Choose from straight nozzles, T-nozzles, nozzles with a screw support bearing, and elongated distribution nozzles for a variety of metering, spreading and seasoning applications.
  • Choose from many easy-to-change-out auger options to suit your exact need: flat, square, or round (with or without a center core), continuously welded, polished, or milled from solid bar stock.
  • Increase holding capacity and extend time between refills with optional hopper extensions.
  • Minimize housekeeping and air quality problems with optional dust collection hood. Keeps material in process; makes work environment safer.
  • Handle spreading and seasoning applications with optional elongated distribution nozzle. Ideal for feeding seasoning drums or distributing across moving conveyor belts.
  • Use in coating drums, across moving conveyor belts or for filling wide surge hoppers.
  • Alert your control system when material is getting low in the hopper. Optional level sensors help workers keep hopper full and feed rate consistent.
  • Integrating load cells and instrumentation enables the equipment to perform more automatically, immediate feedback that material was delivered, and increased performance.
  • Volumetric and gravimetric options are available. The best option for your process will be determined by the specific material used and unique details of your application.

PosiPortion Feeder Specifications

Standard Models and Theoretical Capacities

Standard models and theoretical capacities | Hapman.com

Nominal Feeder Frame Dimensions

Nominal feeder frame dimensions | Hapman.com


Compact, Portable Systems for Conveying, Metered Feeding, and Solid/Liquid Combining

Our engineered Vac-Feeders are a unique combination of conveying, metered feeding, and dry/liquid combining equipment for small batch or low volume applications. The Hapman Vac-Feeder was developed from an increasing industry need for a cost-effective method of unloading small batches of dry bulk material and pre-mixing the material into a solution. Typically, the low volume material handling applications were saddled with a labor-intensive, time-consuming process because the batch operation did not justify the cost of large capital equipment. Recognizing this growing trend, our engineering team worked with several customers to develop the optimal equipment for the job. The Vac-Feeder has a small footprint, lower cost and is frame mounted.

Operating Hapman Vac-Feeders

The Vac-Feeder operation begins with a special filtered vacuum conveyor that uses an electric motor to create suction. The vacuum conveyor comes with an integral filter for capturing material dust. The material is fed from the conveyor into the surge hopper of the feeder, which then accurately and precisely feeds material into an educator system which incorporates the dry material with the liquid. The operator can see the volume of material in the hopper at all times using a sight window that is integral to the hopper. The educator creates a venturi effect, pulling the dry material into the liquid stream, quickly combining the two. The system is engineered for accurately incorporating the two elements depending on the dry material volume, bulk density of the material, and type and volume of liquid introduction.


Vac-Feeder Specifications

Standard models – Stated capacities are theoretical based on assumed parameters



Our applications experts will work with you to create the exact bulk material handling systems to meet your specific needs.

PosiPortion™ Volumetric Screw Feeder/Seasoner – The equipment shown, engineered for an accurate +/- 1% metered dose based on volume and time, is specifically designed for seasoning drums or tumble coaters for snack food and candy manufacturers. Precision product dosing is measured by keeping the screw full and measuring the volume of material in the feeder coupled with turn speed, pitch of flights, and turning time.

  • Model 321-SV – Equipped with a 304 stainless-steel distribution nozzle with 42″ projection and herringbone slot pattern. The dosing screw has a nominal outside diameter of 4″ standard pitch and a root diameter of 1″. Flow range estimated at 14-230 ft3/hr, approximately 172 ft3/hr @ 60 Hz based on free-flowing powders.
  • Model 241-SV – Engineered for smaller batch operations designed with a nozzle OD of 1-1/2” with standard pitch and a root diameter of 3/8”. The capacity range of the 241-SV is approximately .88-14.2 ft3/hr or 10.6 ft3/hr @60 Hz based on free-flowing powders.

The long throat design maximizes natural in-flow allowing for easy handling of difficult ingredients and compounds. Featuring a FDA hopper design and food grade finishes on all contact surface including the hopper interior, screw and nozzle.



Bag Dump Station with Helix Flexible Screw Conveyor and Loss-in-Weight (Gravimetric) Screw Feeder – The system pictured uses the feeder as the control point, measuring and metering the flow of material based on a pre-set flow rates and minimum accumulation levels. When the reading on the scale drops below set-point, the Helix Flexible Screw Conveyor is called to feed additional material from the main hopper into the feeder hopper. The lighted alarm notifies workers when additional bags of material need to be emptied into the main hopper. The dump station with integral dust collector provides workers a safe and clean way to quickly empty bags into the hopper. The entire system is skid-mounted on casters for easy mobility throughout the plant.




Volumetric PosiPortion Feeder With Bag Dump Station and Removable Self-Contained Dust Collector – The equipment shown consistently meters powders into a process on a volumetric basis. This use of the PosiPortion Feeder and Bag Dump Station is especially efficient in solving dust control/containment challenges in standalone feeder applications.



Stainless Steel PosiPortion Feeder With Hopper and Extended T-Nozzle – The equipment shown includes an extension hopper that is sized for quick refill and optimizing feed rate accuracy. An extended T-nozzle directs material to a process inlet, as well as a load cell. In conjunction with the PosiPortion feeder, the load cell provides the means for continuous weight-based feed rate control, ensuring the delivery of highly accurate batches by weight. Additionally, the load cell can be used to provide the net weight of material used in a process.



industrial gravimetric and volumetric screw feeders

PosiPortion Feeder | Hapman.com

The industrial gravimetric and volumetric screw feeders we manufacture are used in a wide range of bulk material handling applications. Whether your material is free-flowing – such as pellets and powders – or more difficult to move – such as pigments, fibers, and sticky or lumped material – we have the material handling equipment and experience to effectively and accurately meter your product.


Product Brochures
Product Brochure: Feeders
Corporate Brochure



  • Precise Measurement
  • Cleanability
  • Low Maintenance
  • Product Degradation



See what our customers frequently buy with the Feeder

Vacuum Conveyor
Bulk Bag Unloader
Tubular Drag Conveyor


Headshot of Hapman's Byron Viler

Contact: Bryon Vlier

Product Specialist
(269) 382-8288
Email Me


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