A high-pressure vane pump supplier proves its claim with a per-unit test record and a stated rating basis, not with a catalogue number. Before you approve the order, establish three things: the pressure basis (continuous, intermittent, or peak), the conditions, and whose test bench produced the number.
That sounds straightforward until two quotes for the same frame letter differ by 30 bar. A distributor page for Parker T7 pumps, checked in November 2026, lists the T7B at 320 bar continuous and 350 bar peak. Parker’s T7B data, as republished by distributors, puts the same frame at roughly 290 bar continuous and 320 bar intermittent.
The gap is not rounding; it is the difference between a pump that holds a die-casting circuit and one that runs above its rating every cycle.
This guide is for buyers comparing high-pressure vane pump suppliers who claim to meet the same specification. It assumes you have chosen a series; the high-pressure vane pump guide covers pressure classes.
Key Takeaways
- A rating is only comparable when it names the pressure basis, the speed, the fluid, and the temperature; a bare “320 bar” cannot be specified against.
- Catalogue ratings, type-test reports, and per-unit test records prove three different things, and suppliers quote them interchangeably.
- Parker’s T6/T67/T7 catalogue gives frame-specific maxima (A 300, B 320, C 275, D 280, E 240 bar), with continuous ratings below the intermittent ones; confirm the frame before you accept any single number.
- ISO 9001 verifies process control at a defined scope. It does not verify that a pump holds pressure.
- The HVQ reached 400 bar, is no longer manufactured by its owner, and does not interchange with V or VQ, so provenance and rating basis matter more there than anywhere else.
What a high-pressure vane pump supplier should be able to prove
A pressure rating is a verified claim about one pump at one set of conditions. It combines a pressure level, a duty basis, and the conditions the rating assumes. Remove any one of those and the number stops being a specification.
The duty basis matters first. Continuous pressure is what the pump holds indefinitely within its rated life; intermittent pressure applies for a defined part of the cycle; peak pressure is a momentary ceiling set by the relief valve. A pump rated 320 bar intermittent is not a 320 bar pump in the sense a system designer means.
The conditions matter as much. A vane pump holds pressure by keeping the vane tips sealed against the cam ring while the vanes slide in their rotor slots. Higher pressure loads the extended vane on its side, raising tip and ring wear, internal leakage, and heat.
The same pump therefore carries a different rating at 1,500 or 2,500 rpm, on ISO VG 46 or water glycol, at 40 or 70 °C. A supplier who answers “yes, it holds 250 bar” has not answered the question. The useful answer names the conditions: “250 bar continuous at 1,500 rpm on ISO VG 46 at 50 °C, derated to 210 bar above 60 °C.” Ask for that sentence in writing.
Three kinds of pressure evidence
Suppliers use the word “tested” for three unrelated things. Knowing which one you have been offered is most of the verification job.
| Evidence | What it proves | Who produces it | What to ask for |
|---|---|---|---|
| Catalogue or series rating | Design intent for a family of pumps | Manufacturer’s product literature | Frame letter, displacement, rating basis, and the conditions behind the number |
| Type test or rating verification | The pressure-containing envelope survived a defined fatigue and burst programme | Manufacturer or an independent laboratory | The standard used, report reference, date, and the exact configuration tested |
| Per-unit test record | This serial number held pressure and delivered flow on a bench | The supplying factory’s test department | Serial number, test conditions, hold time, leakage limit, and instrument calibration |
Most quotations give you the first and imply the third. That is the gap.
The standards sit in the middle tier. NFPA/T3.9.22 R2-2000 (R2024) is the pressure rating supplement to NFPA/T2.6.1 R2-2000, covering a rated fatigue verification programme, a rated burst pressure programme, a failure distribution, and verification by similarity. ISO 10771-1:2015 covers fatigue pressure testing of metal pressure-containing envelopes and includes an annex addressing pumps and motors.
For performance rather than envelope strength, ISO 4409:2019 defines how to test and present steady-state performance for positive-displacement pumps and motors. That is the method behind the flow and efficiency figures on a test record.
A type test is not a substitute for a per-unit record. One pump passing a bench check says nothing about the fatigue life of the design; a design verification says nothing about whether the unit in the crate was assembled correctly.
For the full comparison, our vane pump vs. piston pump comparison covers the crossover decision.
Reading a per-unit pressure test record
A usable record identifies the pump, states the conditions, and gives a pass or fail against limits agreed before the test. Nine fields should be present.
- Model code and full ordering code, including frame, displacement, mounting, shaft, rotation, and port configuration.
- Serial number, matching the number on the nameplate and on the packing list.
- Test fluid, viscosity, and temperature, for example, ISO VG 46 at 50 °C, with a note on whether the temperature was stabilised.
- Shaft speed for each test point, in rpm.
- Test pressures, stated separately for continuous, intermittent, and any proof or peak check.
- Hold time at each pressure, in minutes.
- Delivered flow at rated pressure, with the test speed stated, and case-drain leakage reported separately. Combining the two hides internal leakage.
- Relief valve setting, where the pump is supplied with one.
- Instrument calibration status and date, plus the signature of the person who ran the test.
Two numbers do most of the work. Volumetric efficiency is delivered flow divided by theoretical flow (displacement multiplied by speed); compare it with the datasheet figure at the same speed and pressure. Case-drain leakage belongs in its own column, because a record that reports only total flow hides the difference between a healthy pump and a worn one.
Field note: “100% tested” describes how many units were checked, not how hard. A two-minute run at 50 bar is a 100% test. Ask what pressure was held, for how long, and against which limit.
Pressure testing is bench work. Guard the area, use a gauge suited to the test pressure, and do not hold pressure on an installed circuit to check a supplier’s claim.
The rating-basis question, worked through on the T7
The fastest way to see why the basis matters is to compare published T7 figures.
| Source | T7B claim |
|---|---|
| Parker T6/T67/T7 series page | Series rated up to 320 bar; port 1 continuous 75 to 290 bar, intermittent 90 to 320 bar |
| Parker T6/T67/T7 catalogue, frame table (distributor-hosted copy) | Frame-level maximums: 300 bar (A), 320 bar (B), 275 bar (C), 280 bar (D), 240 bar (E) |
| Parker T7B data, distributor summary | 320 bar intermittent, 290 bar continuous on standard fluid; 240 bar intermittent, 210 bar continuous on HF-3 |
| A distributor’s T7 page, November 2026 | 320 bar continuous, 350 bar peak |
Read the first three rows and the pattern is clear: the frame letter changes the maximum, and the continuous figure sits below the intermittent one. In the fourth row, the continuous rating has been moved up to the maximum, with a peak figure above it. A buyer who specifies from that page is asking for 30 bar more than the OEM continuous rating on every cycle.
The frame table is in a distributor-hosted copy of Parker’s T6/T67/T7 catalogue. Check your frame there, and against a Parker-controlled copy, before accepting a single series number.
The question that resolves it fits in one email:
For model [full code], please confirm the maximum continuous pressure and the maximum intermittent pressure, each with its time limit, at [speed] rpm on [fluid and viscosity] at [temperature]. Please state whether these figures come from the OEM catalogue or from your own testing, and attach the test record for the unit quoted.
Ask before the quote is finalised, not after the pump arrives. A supplier who works from OEM literature will answer precisely; one who cannot has told you something useful.
Does the supplier publish a derating table?
The rating assumes conditions, so ask for the curve or table that shows how pressure falls with speed, displacement, fluid, and temperature, not a sentence. The T7B example shows the size of the fluid correction: 290 bar continuous on standard hydraulic fluid becomes 210 bar continuous on HF-3. A single number per series will not transfer to your bench.
Certifications: what an ISO 9001 scope tells you
ISO 9001:2015 certifies a quality management system at a defined scope. It says the supplier controls its processes, not that the pump holds pressure, and it does not replace a test record.
The scope statement is where most checks stop too early. A meaningful scope names a manufacturing activity and a product family, for example, “manufacturing of hydraulic gear pumps and motors.” A scope covering “trade and distribution of hydraulic components” tells you the certified entity sells pumps, not who makes them.
Four checks take a few minutes:
- Certificate number and issuing body. Confirm both against the certification body, not against the PDF alone.
- Legal entity and address. The certificate must belong to the company that will invoice you, at the site that will supply you.
- Scope and standard edition. Confirm ISO 9001:2015 and read the scope wording.
- Accreditation and status. Check the certificate in IAF CertSearch, which returns the standard, scope, status, and certification body. If it does not appear, treat it as unverified until the certification body confirms it in writing.
ISO itself does not certify anyone. Accredited certificates are verified through the certification body or the accreditation body.
Two more documents belong in the conversation. A certificate of origin establishes where the goods were made, which matters when a listing implies a European or Japanese origin. A cleanliness specification should name an ISO 4406 class, the test method, and a per-lot certificate; the ISO 4406 cleanliness guide explains the three-number code.
The HVQ provenance problem
The HVQ is the extreme case of a rating that cannot be verified from a listing. It reached 5,800 psi (400 bar); it does not interchange with the V or VQ series, and Danfoss no longer manufactures it. The VQH remains in production at 3,500 psi (241 bar). The 400 bar HVQ is still the ceiling among the high-pressure vane pump types in common use. For broader information, our high-pressure vane pump series guide covers the full cross-brand map.
That leaves a market where the headline rating is genuine, the original manufacturer has left, and supply comes from clone production. One clone catalogue lists a 20HV/HVQ family from 7.0 to 45.5 cc/rev but gives a single pressure band for the whole family, which is not the same as a per-model rating. Clone literature has to be read line by line.
If you are buying an HVQ, or any pump described as a 400 bar vane pump, verify three things before the order: the original rating basis, including whether 400 bar was continuous, intermittent, or peak; the test standard and evidence behind the clone’s rating; and cartridge and spare availability, since a discontinued design supported by one supplier is a supply risk as much as a technical one. Verify dimensional interchange separately, covering mounting flange, pilot, bolt pattern, shaft, rotation, and port positions.
For the in-production alternatives, the 45VQH single vane pump page, the Denison vane pump range, and the TOKIMEC SQP series give a cleaner starting point, because the rating basis can be checked against a current OEM document.
The RFQ and purchase order language that gets evidence
The most reliable way to receive evidence is to make it a condition of the order. Three clauses cover most of the risk.
1. Rating basis and conditions. “The pump shall be rated for [X] bar continuous and [Y] bar intermittent, at [speed] rpm, on [fluid] at [temperature]. The supplier shall state the source of these ratings and any derating that applies at the specified conditions.”
2. Per-unit test and record. “Each pump shall be supplied with a test record stating model code, serial number, test fluid and viscosity, fluid temperature, speed, test pressures and hold times, delivered flow at rated pressure, case-drain leakage, relief valve setting, instrument calibration dates, and pass or fail against the agreed limits. Records shall be retained for [X] years and supplied on request.”
3. Cleanliness. “Fluid cleanliness at dispatch shall meet ISO 4406 class [code], verified by [method], with a per-lot certificate.”
Two optional clauses are worth the effort on a first or high-pressure order. A witness or hold point lets your inspector watch the pressure test or review the record before packing. Sample approval, where one or two units are tested before the batch is released, catches a process problem while it is cheap to fix.
Answers that should stop the order
| The supplier says | What it may mean | What to ask next |
|---|---|---|
| “100% tested before shipment” | A short run test, not a rating verification | Pressure held, hold time, pass limit, and the record for your serial number |
| “Same as Parker” or “100% interchangeable” | Dimensional similarity claimed, pressure class unstated | Frame letter, rating basis, and a pressure-class comparison |
| “320 bar” with no basis | A maximum, possibly intermittent or peak, possibly a different frame | Continuous and intermittent ratings at your speed and fluid, in writing |
| ISO 9001 logo on a PDF | Certificate may belong to another entity or cover trade only | Certificate number, legal entity, scope, issuing body, and accreditation |
| “HVQ, 400 bar, available” | Clone of a discontinued design with unclear provenance | Original rating basis, test standard, and dimensional verification |
Frequently asked questions
Is “100% tested” enough?
No. It states how many units were checked, not how hard or against what limit. Ask for the test pressure, hold time, pass criteria, and the record tied to your serial number.
What is the difference between proof pressure and rated pressure?
Proof pressure is a one-off check that the pressure-containing envelope survives a multiple of working pressure without leaking or deforming. Rated pressure is a verified capability over a duty cycle. Passing a proof test does not establish a continuous rating.
Can a T7 vane pump run at 320 bar continuously?
Not according to Parker’s published data, which places the T7B at about 290 bar continuous and 320 bar intermittent on standard fluid. Some distributor pages quote 320 bar continuous; confirm the basis for your frame and fluid in writing.
Does ISO 9001 prove the pump will hold pressure?
No. It shows that the supplier’s processes are controlled within a stated scope. Pressure capability is proven by the rating basis and the test record.
Why is the HVQ treated differently from other vane pumps?
Because it is the only 400 bar vane lineage, it is no longer made by its owner; it does not interchange with V or VQ, and the current supply comes from clone production. The rating may be genuine, but the evidence has to be checked per supplier.
Conclusion
Pressure claims are easy to print and hard to verify. The method is consistent:
- Ask for the pressure basis, the speed, the fluid, and the temperature, in writing.
- Separate catalogue ratings, type-test reports, and per-unit records, and ask for the one your order depends on.
- Confirm the frame letter before accepting any single series number.
- Check the ISO 9001 scope and the certificate’s legal entity, not just the logo.
- Treat a discontinued high-pressure lineage as a provenance question, not a specification.
The next step is a short email, not a purchase order. Send the nameplate photograph, the duty cycle, the required continuous pressure, and the fluid you run, and ask for the rating basis and the per-unit record with the quotation. If the answer arrives with conditions, hold times, and a serial number attached, you have found a supplier who can be held to the claim.
Looking for a high-pressure vane pump supplier that documents the rating before the invoice? Send your nameplate details, duty cycle, and required pressure to LOYAL INDUSTRIAL PTE. LTD., and request a specification-matched quotation with a sample per-unit test record from the supplying factory for the series you are considering.
