General engineering guidance for technical review. Examples explain the method and do not establish specifications for a supplied product.
Sintered metal filter RFQ: what to specify
You do not need a completed engineering specification to begin a discussion. Send the process or replacement task, the result you need, the fluid and contaminants, any known flow conditions, and the installation reference. A clear unknown is useful; a guessed number can send the selection in the wrong direction.
On a small screen, scroll the table sideways to see every column.
| Field | Useful first answer |
|---|---|
| Task | New installation, replacement or process change; what currently fails. |
| Required result | Downstream protection, solids recovery or another specific objective. |
| Fluid and contamination | Names, phase and known constituents; note what remains unknown. |
| Known conditions | Flow with units; temperature and pressure if available. |
| Installation reference | Permitted drawing, sketch, photos or existing identification; constraints on changes. |
You can start with incomplete information
Label each entry as measured, estimated, required or unknown. The first inquiry can request feasibility review rather than a final quotation.
Gather detail in stages
Collect the next data when the review needs them. Treat operating pressure, permitted pressure loss and mechanical differential-pressure limits as different fields. For gas, state reference conditions for standard or normal volume as well as the operating conditions. For liquids, provide viscosity at the relevant temperature when available.
On a small screen, scroll the table sideways to see every column.
| Stage | Information to resolve | Decision enabled |
|---|---|---|
| Technical shortlist | Composition and concentrations; min/normal/max flow; temperature, pressure and transients; particle target. | Candidate materials and structures for review. |
| Installation review | Controlled drawing, critical dimensions and tolerances, seals, connections, flow direction. | Fit and assembly review. |
| Performance review | Retention definition, hydraulic target, solids loading, cleaning and recovery criteria. | Relevant evaluation plan and open technical risks. |
| Before order | Accepted drawing and requirements, unresolved deviations, inspection scope, quantity and delivery terms. | A quotation and order on an agreed basis. |
A fictional filled inquiry
Every value in this example is invented to show how to complete the worksheet. It is not a customer case, an available product specification or a recommended operating point. “Required” describes the imaginary buyer’s request, which would still need review.
On a small screen, scroll the table sideways to see every column.
| Field | Example entry | Status |
|---|---|---|
| Task | Replace a particle filter ahead of a spray nozzle; cleaning frequency has increased. | Fictional background |
| Fluid | Process water; composition and chloride concentration not yet available. | Unknown — request analysis |
| Flow | 20 L/min normal; peak flow not measured. | Estimated / unknown |
| Temperature | 25 °C during normal running; cleaning temperature unknown. | Estimated / unknown |
| System pressure | 3 bar gauge at filter inlet; transients unknown. | Estimated / unknown |
| Clean pressure loss | ≤0.2 bar at normal flow across the complete filter assembly. | Buyer requirement — unverified |
| Filtration target | Protect nozzle; no particle-size acceptance criterion yet. | Unknown — obtain downstream requirement |
| Installation | Sketch F-01 rev A; length and sealing dimensions still to be measured. | Incomplete reference |
| Cleaning | Current water rinse; chemicals and effectiveness not recorded. | Incomplete |
| Quantity and objective | Evaluate 2 samples after technical review; destination Germany. | Fictional request |
| Open questions | Confirm particle target, flow peak, fluid analysis, fit and cleaning limits. | Actions before selection |
Attach a useful drawing or sketch
For a replacement, show overall length, outside diameter, bore where relevant, active filtering length, connections and seal surfaces. Add flow direction and the critical dimensions that govern fit. Give each revision a date or identifier; photographs support the sketch but cannot establish hidden dimensions.
Only share documents you are entitled to provide. Mark dimensions that have not been checked. Keep the original part number as a reference for investigation, without treating it as proof that another assembly is equivalent.
- Show where a length or diameter is measured, not just its number.
- Identify seal material if known, and mark unknown seals explicitly.
- State whether the housing and mating parts can change.
Decide what must be confirmed before purchase
Use the selection worksheet to separate facts, purchaser requirements and unanswered questions. Before order, agree the relevant drawing, material identification, performance evidence and inspection scope. Availability and applicability of documents must be confirmed for the proposed element.
Include quantity, destination and the decision requested: feasibility discussion, sample evaluation or quotation against an approved requirement. Keep the completed worksheet with the inquiry so that later answers revise the same record rather than starting a different specification.
A practical first action
Download and fill the selection worksheet, or start a short inquiry with the known facts. Leave unknown fields explicit; do not copy a competitor’s values into your requirements.
