PFM-SC-S Loss-In-Weight Screw Feeder

THAYER Model No.
Approximate Feed Rate Range (ft³ hr)
0.14 – 23
Scale Capacity (pounds)
30 – 500
Scale Suspension Type
Weigh Hopper Liquid Capacity (ft³)
1.0 – 9.75
Available Screws Diameter (in)
1.0 – 2.0
Load Cell Type
Strain Gauge / LVDT
Typical Materials Handled


PFM-SC-S Loss-In-Weight Screw Feeder

The THAYER Model PFM-SC-S is a small capacity Loss-In-Weight-Feeder designed to assure accurate and uniform feeding of a wide range of materials, from freeflowing to very fine cohesive powders.

Exclusive Powder Feeder Technology

Patented “U-trough” feed chamber with independently driven agitator assures precise, reliable delivery of material to the feed screw. Eliminates material build-up, controls material aeration and delivers a steady constant flow of material.

Fast and easy to clean

The Model PFM-SC-S is designed for fast, easy and thorough clean out. Feeder completely disassembles in less than one minute. High quality, rugged, stainless steel construction assures years of reliable, trouble free operation.


Thayer Scale’s built in Automatic Test Weight Lifter (“ATWL”) provides a means for automatically applying a known test load and going through a calibration sequence on computer or push-button demand to check scale calibration. A “foolproof” self checking software algorithm in the feeder control instrumentation prevents erroneous calibration.

The test weight calibration method has proven accurate and reliable over decades of in-plant use. Unlike material sampling, it is always clean, fast and safe. Unlike electronic signal simulation, it actually tests the performance of critical electro-mechanical components under the full deflection range of the load cell.

  • Accurately measures load regardless of load position
  • Immune to support structure deflections and process vibrations
  • Inherently self aligning to gravity
  • Nulls out heavy tare loads
  • 1,000% over load capacity
  • Scale may be suspended from above or supported below
  • Immune to shock or impact loads
  • Easily accessible load cell can be accessed without removing the feeder

Patented “FMSS” (Force Measurement Suspension System) Cable Scale Technology

fmssThe Thayer Cable Scale (patented) is the most rugged and forgiving Load Cell Weighing System available on the market. It can take more physical abuse and can tolerate more foundation distortion/deflection than all other known designs.

The exclusive Thayer Scale “FMSS” Cable Suspension design provides extremely high sensitivity. Feeder “dead load” is mass-counterbalanced so that only material weight (live load) is measured. This feature helps assure excellent control in “noisy” environments.

All of the articulate parts of the scale mechanism are supported from “axially inextensible, but laterally yieldable” suspension elements (stainless steel pre-stressed aircraft cable), which are arranged to hang freely, thereby avoiding any appreciable spring or hysteresis effects, variations in mechanical advantage, or binding due to imperfect leveling.

Because of this unique mechanical property of the force transmission system, any laterally directed forces and shocks on the scale or its supported machinery can not cause destructive shear and bending stresses to develop in the elements themselves or at the load cell junction. The system, being yieldable in the lateral direction, is therefore effectively and completely protected by using laterally placed “stops” in proximity of the weighed structure.

Weight loss measurement is done by either Thayer’s LC-137 LVDT Load Cell or NTEP approved strain gauge load cell depending on application requirements.