A gauss test measures magnetic flux density at a defined point; a pull test measures force against a specified test piece. Neither alone establishes iron-removal performance in silica powder. Use repeatable magnet checks alongside a process trial with agreed sampling and acceptance criteria.
1 tesla equals 10,000 gauss, but neither unit measures removal rate
Gauss and tesla describe magnetic flux density. A reading depends on the probe position and orientation, including its distance from the working surface. A supplier’s maximum surface reading cannot be treated as the field everywhere in the powder stream. Record the measurement location, probe arrangement, instrument identification and calibration status so that a later reading can be compared with the same baseline.
A magnetic rod’s external sleeve also matters: record whether a measurement refers to the accessible working surface or another part of the assembly. For dimensions and installation information, see our magnetic tube page. A material grade, surface reading and installed removal rate are three different specifications.
A pull-test result needs a defined test piece and setup
Pull tests report force, typically in newtons or pounds-force. There is no universal conversion from a gauss reading to a pull-test result. Test-piece material, dimensions, contact, gap and pull direction affect the result. Comparing values obtained with different fixtures can therefore be misleading.
For repeat inspections, retain the same approved procedure and fixture, and compare the result with the equipment’s recorded baseline. Follow the equipment supplier’s safe inspection procedure; this article does not specify a universal load, release method or pass threshold. Eriez’s pull-test guidance describes its kits as a way of monitoring magnetic strength over time.
Compare three manufacturers’ inspection guidance without inventing a performance ranking
| Public reference | What it addresses | How to use it in a purchase specification |
|---|---|---|
| Industrial Magnetics, Inc. | Gauss and pull testing | Specify which measurement is required and record the setup. |
| Puritan Magnetics | Repeatable on-site checks | Compare equivalent locations and inspection conditions. |
| Eriez | Pull-test kits and monitoring | Use the relevant procedure and baseline rather than an unrelated product’s value. |
These sources describe inspection approaches. They are not evidence that one manufacturer’s separator removes more iron than another under the same silica-powder conditions.
Keep the 80µm contaminant statement separate from magnetic measurements
JINHONG’s JH-LX application statement concerns iron impurities of approximately 80µm diameter. It is not the silica feed particle size, a gauss reading, or a performance claim for every standalone tube. Rod dimensions and magnetic configuration can be customized; the installed arrangement and powder conditions still need assessment.
See the JH-LX self-cleaning magnetic separator for the product scope. A claim about this complete machine should not be transferred to a magnetic grate or rotary separator without separate evidence.
Report removal and product recovery as separate trial outcomes
Define the contaminant, sampling method, analytical detection limit and acceptance criteria before testing. Retain distinguishable feed, product and collected-contaminant samples. Report throughput and product loss alongside the agreed contaminant measurement. A reduction in concentration is not automatically the same as the fraction of contaminant mass removed if product mass also changes.
For example, if a controlled comparison finds removal rates of 50% and 65%, the latter is 1.3 times the former and 15 percentage points higher. These numbers illustrate the calculation; they are not results from a trial reported in this article. Do not substitute a gauss test or pull test for the process measurement. Our silica-powder iron-removal guide explains the trial inputs.
Frequently asked questions
Can a higher gauss value guarantee better iron removal from silica powder?
No. The field at the contaminant, its magnetic properties, powder flow and equipment arrangement all matter. Compare instruments under repeatable conditions and verify separation using representative material.
Can I convert a magnetic separator pull-test result into gauss?
There is no universal conversion. Force depends on the test piece and magnetic circuit as well as the field. Keep both measurements tied to their stated procedures.
Should magnetic separator acceptance use only a pull-test certificate?
A certificate can document a defined magnet inspection. Process acceptance also requires agreed material, sampling and performance criteria; a certificate alone does not establish the residual iron level in your powder.
What should I send when requesting a silica-powder separator?
Provide powder type and particle distribution, moisture, bulk density, temperature, flow rate, installation dimensions, contaminant information and the intended acceptance method. Identify any existing test procedure that the proposed equipment must support.