InterProcess Sp. z o.o. | Solutions for industry
The DSL G range
Three sizes, one operating principle
Every DSL G feeder comprises a hopper, a feed chamber with the feeding element, a horizontal agitator and a drive. The whole assembly rests on load cells: the controller measures the loss in weight, derives the actual mass flow and trims the screw speed with a PID loop. Changes in bulk density have no effect on the result, because mass is controlled, not volume.
Feed rates are volumetric. Mass flow = feed rate × bulk density (e.g. 200 l/h × 0.55 kg/l ≈ 110 kg/h). The minimum applies to the smallest full-flight screw at 10 rpm, the maximum to the largest spiral at 200–250 rpm.
DSL35 G screw feeder
Micro-ingredients with laboratory accuracy
The smallest model in the range, designed for low feed rates and high-value ingredients. Screws of ø18–35 mm deliver an even stream at rates of a kilogram per hour, and the steep-walled 30–65 l hopper ensures uniform discharge. The low overall height allows the feeder to sit directly above a recipe scale, mixer or extruder inlet.
Configuration
Feed chamber with one horizontal agitator, hopper of 30, 40 or 65 l with lid and refill spigot, outlet with discharge tube. Weighing frame with two C3 load cells. Optional weighing controller with HMI in a stainless-steel enclosure, EHEDG hygienic version and ATEX design.
DSL35 G data
- Feed rate1 – 450 l/h
- Feeding elementscrew or spiral ø18 – ø35 mm
- Hopper30 · 40 · 65 l
- Typical materialsmicro-ingredients, colourants, flavourings, APIs
DSL75 G screw feeder
The production-line standard
The most frequently specified model for recipe ingredients on continuous and batch (batching) lines. Feeding elements of ø35–74 mm handle fine cohesive powders as well as granules, and 100–300 l hoppers let the refill interval be matched to line throughput. The typical unit in multi-ingredient stations, where several DSL75 G feeders run in parallel onto a common scale or mixer.
Configuration
Feed chamber with one or two horizontal agitators, hopper of 100, 200 or 300 l, weighing frame with three C3 load cells. Refilled manually, from a big bag or from a rotary valve with automatic top-up on the low-level signal. Optional additional vertical agitator, EHEDG hygienic version and ATEX design.
DSL75 G data
- Feed rate7 – 5,000 l/h
- Feeding elementscrew or spiral ø35 – ø74 mm
- Hopper100 · 200 · 300 l
- Typical materialsrecipe ingredients, premixes, fillers
DSL150 G screw feeder
Industrial throughput
The largest model for major ingredients and high mass flows. Feeding elements of ø74–150 mm, cylindrical hoppers from 400 to 2,400 l and a weighing frame prepared for refilling from big bags, a rotary valve or pneumatic conveying.
Configuration
Cylindrical hopper ø850 mm (400 or 600 l) or ø1,200 mm (1,200, 1,800 or 2,400 l), feed chamber with two horizontal agitators, weighing frame with three C3 load cells sized to the mass of the full hopper. Automatic refilling from a silo, big bag or pneumatic conveying with hopper venting. Optional material loosening system in the hopper and ATEX design.
DSL150 G data
- Feed rate70 – 25,000 l/h
- Feeding elementscrew or spiral ø74 – ø150 mm
- Hopper400 · 600 l (ø850 mm)
1,200 · 1,800 · 2,400 l (ø1,200 mm) - Typical materialsmajor ingredients, high mass flows
Feeder selection
Not sure which model to choose? Complete the selection questionnaire
Material data, the required feed rate and the operating mode are all our engineers need to select the feeder size, feeding element and design. We reply with a proposed configuration and a quotation.
Common to the whole range
Same weighing system, same materials
The models differ in the size of the feed chamber, hopper and feeding element. The weighing system, controls, materials and design variants are identical, so feeders of different sizes can be combined in one station on a common controller.
DSL G installations · click to enlarge
Selecting the feeding element
Spiral or full-flight screw?
The choice of screw or spiral determines the evenness of the stream and the stability of control. The element type is matched to the material properties, not to the feeder size.
Not sure which element to choose? We run feeding trials on the customer’s own material: the choice of screw or spiral is confirmed by measurement, not by catalogue data alone.
Arrange a material trialDesign variants
EHEDG hygienic version and ATEX design
EHEDG-compliant hygienic version
The standard design already meets food-industry requirements: all product-contact materials are FDA-approved or stainless steel.
For demanding duties we offer a design to EHEDG guidelines: feed chamber and frame engineered for cleanability, feeding element and agitator removable without tools, 316L steel, interiors and welds ground to Ra<0.8 µm, aseptic motors without cooling fins or fan.
Lubricants NSF H1 class only. Electrical enclosures optionally to the Rittal HD (Hygienic Design) standard: stainless steel, sloping surfaces, resistant to high-pressure washdown.
Feeders for explosive atmospheres (ATEX)
For dust explosion zones we supply feeders compliant with the ATEX Directive: certified electrical components, drives and sensors in the appropriate category, and continuous equipotential bonding to dissipate electrostatic charge.
Gravimetric vs volumetric
Which feeding method should you choose?
A volumetric feeder runs the screw at a fixed speed and assumes constant bulk density; without a feedback loop every change in the material becomes a feeding error (typically ±1–5%). A gravimetric feeder measures the loss in weight and trims the speed in a closed loop, holding the error below ±0.5% whatever the material. The difference matters for multi-ingredient recipes, high-value materials and quality audits.
| Parameter | Gravimetric loss-in-weight | Volumetric |
|---|---|---|
| Measuring principle | Continuous weight-loss measurement | Constant volume per unit of time |
| Accuracy (continuous feeding) | <±0.5% of set point | ±1–5% of set point after range linearisation |
| Accuracy (batch feeding, batching) | ±0.1–0.5% (depends on load-cell range and batch size) | No direct control of batch weight |
| Compensation for density changes | ✓ Automatic, closed loop | ✗ None, requires recalibration |
| Real-time control | ✓ PID controller | ✗ Open-loop control |
| Flow documentation | ✓ Actual mass flow recorded | ✗ Screw speed monitoring only |
| GMP / HACCP compliance | ✓ Full validation and batch traceability | Limited |
| Capital cost | Higher (weighing system + controller) | Lower, simpler design |
| When to choose it | Multi-ingredient recipes, high-value materials, quality audits | Homogeneous materials of constant bulk density |
DSL G feeders can also run in volumetric mode. Simpler duties are covered by our volumetric screw feeders.
Operating modes
Continuous and batch feeding (batching)
Every DSL G works in both modes; switching is done in software. The choice depends on the nature of production, recipe flexibility and throughput.
Continuous feeding (continuous)
Material is delivered without interruption at a controlled mass flow rate. The controller compares the measured loss in weight with the set point and trims the screw speed continuously.
- a steady, closely controlled material stream
- feeding continuous mixers, extruders and reactors
- automatic switch to volumetric mode during hopper refill
- integration of several feeders in a master/slave system
- significant reduction in material giveaway
Dozowanie wsadowe (batching)
A set mass of material is metered out. Once the batch is reached the feeder stops and waits for the next cycle; typical accuracy ±0.1–0.5% for batches above 1 kg.
- precise metering of a target weight with final check
- full traceability of every batch
- support for multi-ingredient recipes
- simplified validation in pharmaceutical production (GMP)
- a proven answer where product changeovers are frequent
Hopper refill without interrupting the feed
The weighed assembly is connected to the refill inlet and discharge pipework by flexible sleeves, so external forces do not affect the measurement. When the hopper level falls below the minimum, the controller starts refilling and the feeder switches to volumetric mode at the last recorded speed. Once refilled, it returns to gravimetric control.
Batch feeding (batching)
Recipe-based feeding
Screw feeders are built into multi-ingredient weighing stations in which each unit handles a separate raw material. The supervisory controller derives the batch size or flow rate from the recipe, in batch (batching) albo continuous.
The weighing concept is dictated by the number of ingredients, the cycle time and the accuracy required:
Gain-in-weight
Weighing into a central scale
The lowest-cost batching arrangement: ingredients are delivered one after another into a common hopper scale. Where requirements are tight, intermediate scales or a travelling scale positioned under each feeder in turn are used. Homogenisation takes place in the mixer.
Loss-in-weight
Feeding straight off the scale
Each feeder has its own scale, so ingredients are delivered in parallel. This shortens the cycle and pre-homogenises the blend as it is fed. In continuous operation it allows a batch mixer to be replaced by a far smaller in-line mixer.
Feeding accuracy
What disturbs the weight signal, and how we compensate
The accuracy of a loss-in-weight feeder depends on the material and the surroundings of the scale, not just the electronics. The most common sources of error and how DSL G compensates for them:
Vibration and shock
Vibration from neighbouring machines and the building structure is damped mechanically in the feeder frame, and the load-cell signal is filtered digitally in the controller.
Pressure differences
Negative or positive pressure in the discharge pipe, a running mixer or nitrogen inerting all falsify the reading. We use pressure compensation at inlet and outlet plus flexible decoupling sleeves.
Bridging in the hopper
Cohesive materials hang up above the screw. The answers are agitators, correctly angled hopper walls and, for the most difficult powders, a hopper with an active loosening system.
Variable bulk density
Bulk density shifts with the delivery batch, moisture content and hopper fill level. The gravimetric controller trims the speed continuously, so the set mass flow stays constant.
Blockages in the feed tube
Caking or fibrous products block the feeding element. We select variable-pitch screws or a shaftless spiral that keeps the material loose by itself.
Short-term accuracy
At very low feed rates what counts is the evenness of the stream second by second. Multi-flight screws, higher speeds on a smaller cross-section and purpose-made discharge tube ends all improve it.
Ratio feeding
Multi-ingredient feeding systems
In continuous ratio feeding, several loss-in-weight feeders deliver ingredients simultaneously onto a common conveyor or straight into the process. Each measures the loss in weight of its own hopper, so the flow of every ingredient is known and controlled independently. One feeder acts as master, the others as slaves, holding a fixed mass ratio to the main ingredient.
A rate change on the master rescales the flows of all slaves, so recipe proportions stay constant whatever the line throughput, and hoppers are refilled without interrupting the feed. InterProcess supplies complete stations: feeder selection, weighing controllers with industrial communication, and recipe automation.
Industries and applications
Applications in key industries
FAQ
Frequently asked questions
Why InterProcess
Why choose our solutions
In-house manufacture
We design and build DSL G feeders in our own works.
Feeding trials
We test your material on a real feeder before you buy.
Turnkey delivery
From design and material trials to commissioning and service.
Experience across industries
Food, chemicals, pharmaceuticals, plastics and power generation.
Safety and hygiene
Systems compliant with ATEX, HACCP, GMP and EHEDG.
Technical support and service
Fast response, 24/7 where required.
