SELECTION / 6 MINUTE READ
Variable-speed pump RFQ: when static head limits the savings
A drive does not erase static head. Compare full- and reduced-speed duty points, system curves and operating hours before accepting an energy claim.
TECHNICAL BUYER LIBRARY
Field Notes for Pump Buyers
Selection logic, standards and inspection checkpoints written for procurement decisions—not keyword volume.
These notes are written for people who have to buy a pump, not for people who have to fill a blog calendar. Each guide is a set of shop-floor checks, numbers and failure modes that belong in an RFQ or an inspection plan. None of them replace project engineering, a named standard, or the manufacturer’s own curve.
Read the fake-304 note before you accept a stainless nameplate. Read the ISO 9906 note before you treat a catalogue PDF as a test. Read the ISO 2858 / ANSI note before you call two pumps a drop-in.
Follow the question that changes the pump choice
For a booster quotation, read the Q-H curve checks, then use the static-head guide when reduced-speed operation is proposed. For a sump replacement, settle solids passage separately from the outlet connection. Chemical enquiries start with a wetted-parts material schedule; the RFQ checklist brings the selected duty and remaining questions into one request.
- Metallurgy
- CF8 versus 201, painted iron, and PMI that actually means something.
- Performance
- Impeller diameter, ISO 9906 grade, power and NPSHr — or it is not a test.
- Dimensions
- What ISO 2858 and B73.1 freeze, and which Chinese series letters fake them.
- Sourcing
- How to write a China RFQ that a factory can answer without guesswork.
SELECTION / 6 MINUTE READ
Sewage pump free passage vs outlet diameter: what to ask before buying
Separate solids passage, discharge connection and fibre handling. Two real catalog examples show what a sewage-pump quote must confirm.
PITFALL / 18 MINUTE READ
How to identify fake 304 stainless steel in Chinese pump castings
A field and lab protocol for CF8 / 06Cr19Ni10 lies: 201 and 430 substitutions, painted iron, low-nickel heats, and the mill certificates that do not belong to the volute you are buying.
SELECTION / 17 MINUTE READ
How to catch a China catalog curve sold as your ISO 9906 test
Typical PDFs, wrong impeller cuts, Grade 3B sold as 2B, 1450 r/min plots at 2900 r/min duties, and the five numbers that must appear on a curve before it is evidence.
STANDARD / 16 MINUTE READ
How to verify a China “ISO 2858 / ANSI B73.1” pump is not a dimensional lie
IS, IH and “ANSI chemical pump” labels do not land on the same bolt holes. Measure f1, shaft height, flange facing and nozzle loads before you call it a drop-in.
SELECTION / 10 MINUTE READ
How to write a China pump RFQ that factories can actually bid
The difference between a price hunt and a bid is a complete duty, a named document pack and one family at a time.
SELECTION / 10 MINUTE READ
Material selection for corrosive and chloride-bearing pump service
Cast iron, 304, 316L, duplex and fluoroplastics fail in different ways. The quote line “stainless steel” is not a selection.
PITFALL / 8 MINUTE READ
Submersible sewage pump checks that belong in the RFQ
WQ-series quotes fail on solids size, starts per hour, cable length, moisture protection and the difference between a cutter and a non-clog impeller.
Questions buyers actually ask
Are these standards interpretations official?
No. They are buyer checklists. The controlling text is the current edition of the named standard and the contract you sign.
Can I use a guide as a specification?
Use it to draft questions. A specification still needs fluid data, duty, materials, documents, tests and Incoterms written for the project.
Why so few guides?
We publish when a note has a procurement use. Thin keyword articles would make the library look bigger and the site worse.