Some powders and bulk solids don’t want to cooperate. They bridge, pack, exhibit inconsistent behavior and push standard feeders to their limits. Thayer Scale loss-in-weight feeders are engineered for exactly these conditions — delivering reliable, controlled material flow where others fall short. Backed by over 75 years of experience, we solve the feeding problems your process can’t afford to have.
Designed with feeding challenges and conditions in mind.
Our loss-in-weight feeders are designed to overcome real-world feeding challenges like packing, ratholing, bridging, dead zones, material flooding and inaccurate weighing.
Engineered for Traditionally Challenging Applications:
- Difficult Powders
- Variable Bulk Solids
- Fragile Materials
- Low Feed Rates (Grams-Per-Min)
- Wide Turndown Requirements
- Feed-Sensitive Processes
Reliable Performance For:
- Titanium Dioxide (TiO₂)
- Clay
- Resin Powders
- Additives
- Food Ingredients
- Specialty Chemicals
- Plastic Compounds
- Mineral Powders
- And More…
Discover Thayer Scale’s Loss-In-Weight Feeders
Our Technology Behind Consistent, Reliable Feeding
Precision at the Core
A volumetric feeding subsystem paired with a fully mass-counterbalanced flexure or cable suspension scale delivers maximum signal clarity and accurate weight measurement — the foundation of stable, reliable feeding.
Design Features That Solve Real Flow Problems
Our proprietary feeder and agitation solutions are designed for the materials that misbehave. Bridging, flushing, adhesion, and cohesion – no flow problem is too hard for us to solve.
Software That Keeps Performance Dialed In
Thayer Scale instrumentation includes powerful routines that continuously optimize feeder output: compensation for disturbances, temperature, and density changes during refill, plus linearization and automated calibration.
How does a loss-in-weight feeder work?
A loss-in-weight feeder is a precision gravimetric feeder that meters bulk materials by continuously measuring the reduction in weight of material over time. Unlike volumetric feeders, which deliver material based only on volume, loss-in-weight feeders use a scale to calculate actual mass flow and automatically adjust feeder speed to maintain a consistent target feed rate.
In operation, material is discharged from a hopper using a volumetric feeding mechanism—such as a screw or vibratory feeder—mounted on a high-accuracy platform or suspension scale. As material exits the feeder, the system measures the rate of weight loss and uses closed-loop control algorithms to correct for disturbances, material density changes, refill events, and environmental factors. This ensures highly accurate, repeatable feeding performance across a wide operating range.
Loss-in-weight feeders are commonly used in continuous processing, batching and blending applications where precise ingredient control is critical. Thayer feeders are especially effective for handling difficult materials prone to bridging, flushing, adhesion, or cohesion. Loss-in-weight feeders are the ideal solution for industries such as plastics, chemicals, food processing, pharmaceuticals, and specialty materials manufacturing.
Benefits of Thayer Scale’s Loss-In-Weight Feeders
🎯 Extended Operating Range
Feeds from a few grams per minute up to over 60,000 pounds/hour.
🧱 Built to Survive
Unlike lightweight designs made for short-term convenience with basic functionality, Thayer feeders are engineered for long-term durability, without compromising accuracy, ultimately reducing total cost of ownership.
🧼 Fast Cleaning Access
Tool-free disassembly for rapid cleaning, product changeover and maintenance.
🌀 Gentle Material Handling
Designed not to degrade or alter the appearance of delicate or fragile materials.
⚙️ Single Load Cell Design
All forces are summed to a single load cell which can be easily accessed or replaced without removing the feeder or weigh hopper.
🔧 Tool-Free Screw Changes
Screw augers can be swapped quickly without special tools.
📐 Flexible Mounting Options
Supports floor-mounted, rotating, stationary, wheeled, forklift-based, or suspended installations.
🛡️ Completely Sealed System
A sealed system allows for improved dust control and supports inert gas purging if required.
Our Loss-In-Weight Feeders Core Technologies
U U-Trough Hopper and Agitator Design
Prevents packing and eliminates dead zones inside the hopper.
⚖️ FMSS Force Measurement Suspension System
Maintains precise weighing accuracy by isolating vertical forces- unaffected by hopper vibration/movement.
🔄 Integrated Material Agitation
Prevents flow issues like bridging, funnel flow, adhesion, and cohesion for consistent material feeding.
🧠 Proprietary Feed Algorithms
Advanced algorithms provide output compensation, disturbance control, linearization, density and temperature compensation, and automated calibration.
🌀 Range of Volumetric Feeding Subsystems
Careful feeder selection ensures precise, reliable metering across a wide flow range from a few grams per minute up to 100,000 lb/hr and minimizes unwanted product degradation.
Loss-In-Weight Feeders – FAQ
Our engineers have compiled the most frequently asked questions about loss-in-weight feeders and LIW technology below.
Q: What is a loss-in-weight feeder and what is the difference between loss-in-weight (gravimetric) and volumetric feeders?
A loss-in-weight feeder is a gravimetric feeding system that continuously measures material flow by weight, not volume, to deliver precise and repeatable feed rates. By monitoring the real-time loss of weight from the feeder and automatically adjusting output, loss-in-weight feeders provide superior accuracy and control for powders, granules and other bulk materials. At the heart of every Thayer Scale loss-in-weight feeder is a scale that has been designed exclusively for the stringent requirements of loss-in-weight feeding. LIW feeders are ideal when accuracy, repeatability, and process stability are critical.
Q: How does a loss-in-weight feeder system work?
The feeder hopper sits on a mass-counterbalanced scale that allows for tracking of only the weight of the live load in real time. As material is discharged through a vibratory feeder, screw, or batching mechanism, the system calculates the rate of weight loss and converts it into a precise feedrate. Closed-loop control continuously adjusts the drive to maintain the setpoint.
Q: What types of metering technologies are available from Thayer Scale?
Vibratory feeders provide gentle, precise movement for free-flowing powders and granules, especially at low feedrates. Screw feeders offer rugged, versatile metering for cohesive or difficult to handle materials over a wide operating range. Ingredient batching systems combine LIW accuracy with automated, recipe-driven control for multi-component processes.
Q: Which loss-in-weight feeder type is best for my application?
Free-flowing, non-cohesive or fragile/friable materials typically perform well with vibratory LIW feeders. Cohesive or bridging materials often benefit from screw feeders. Multi-ingredient or formulation-driven processes are best served by ingredient batching systems. Final selection should always consider flow properties, required feed rate along with several other process goals. Our engineers can help build the right solution for your application.
Q: What feed rate accuracy can I expect?
Typical continuous flow rate accuracy ranges from ±0.25 –1% of setpoint, depending on the material and operating conditions and can be as 0.1 to 0.25% for batch applications. Because LIW feeders measure actual mass loss, they maintain stable performance even when bulk density fluctuates.
Q: How are bridging and flow problems handled?
Proper hopper design and flow aids are key. Solutions include a range of independently driven agitators and optimized hopper geometry for the materials being handled. Matching feeder technology to material behavior ensures consistent discharge and reliable feed control.
Q: Can loss-in-weight feeders integrate with plant automation systems?
Yes. Systems commonly support EtherNet/IP®, Modbus TCP/IP, ProfiNet, and analog I/O. Integrated PID control and recipe management simplify operation and allow seamless communication with existing PLC or DCS platforms.
Q: Is installation and calibration of loss-in-weight feeders difficult?
Installation is typically straightforward with standard mechanical and electrical connections. Commissioning includes calibration, control loop verification, and operator training to ensure reliable performance from start-up through production.
Q: What service and support are available?
Ongoing support includes technical assistance, spare parts, preventative maintenance guidance, and field service when needed. Thayer Scale remains available to optimize performance and troubleshoot as processes evolve.
Q. How can I verify that a loss-in-weight feeder will perform well in my application?
Always work with a manufacturer, like Thayer Scale, who maintains a comprehensive Test Lab in order to be able to run your materials in conditions simulating the actual operating environment to verify design and system requirements.