Define the approval question
A screw-press grade should be accepted for stable concentration and drainage through the installed machine. A candidate selected solely from centrifuge behavior or a quiet settling jar may not answer the permeability and feed-distribution question the press presents.
Identify the product code, representative sludge and operating constraint before requesting a commercial commitment.
Define the conditioning arrangement
Record sludge origin, feed solids, flow, conditioning tank or inline contact, solution addition and machine settings. The industrial biological application gives one common feed context but does not prescribe a universal grade.
Identify how dose and feed are controlled during normal shifts. Include intermittent operation and demand changes if those conditions are part of the purchasing duty.
Screen a practical drainage window
Use a controlled candidate set with reproducible activation and active-dose steps. Observe filtrate solids, floc distribution and drainage instead of ranking only by visible floc size. Keep preparation and age comparable so a polymer change is not confused with improved make-down.
Where bench tests cannot reproduce the machine, use them to narrow candidates and preserve production acceptance as an outstanding requirement.
Run the complete machine comparison
Measure cake, filtrate, throughput and operating stability after the system reaches a suitable comparison state. Record changes in screw speed, pressure-control arrangements or feed settings separately from the initial chemical substitution.
Compare accepted active use and practical control range. A candidate requiring frequent manual correction may not be the best repeat supply even if one short run shows a favorable cake sample.
Challenge a favorable comparison
A clear first filtrate sample can coincide with falling throughput. Check dry-solids loading and cake output before treating that observation as better polymer performance or using it to forecast a lower routine chemical budget.
Record the unresolved boundary with the trial result. An expected operating benefit is not a measured saving or an unrestricted product guarantee.
Keep the acceptance record
| Buying check | Evidence | Acceptance limit |
|---|---|---|
| Contact | Actual conditioning and flow | Trial represents installed system |
| Screen | Drainage and fines response | Useful range retained |
| Machine | Cake, filtrate and throughput | Whole operating duty accepted |
Retain sample identity, measured preparation conditions and synchronized feed and outlet results. Use the record to distinguish an agreed product change from a change in sludge or equipment.
Prepare the supplier brief
Send screw-press and conditioning details, sludge states, current grade, measured dose and the target outputs. State which mechanical adjustments are allowed during the purchase trial and who records them.
Send the evidence through the cationic emulsion sample and RFQ form. Confirm the offered code, availability, packaging and document scope with Gongyi Xinqi Polymer Co., Ltd. before ordering.