ISO 23840:2021

Water hydraulics - Water-hydraulic pumps - Methods of testing and representing basic steady-state performance

This document specifies methods for determining the performance and the efficiency of water-hydraulic positive displacement pumps having continuously rotating shafts. This document provides test equipment, a test procedure under steady-state conditions and the presentation of test results.

Hydraulique à l'eau — Pompes hydrauliques avec de l'eau — Méthodes d'essai et représentation des performances de base en régime permanent

General Information

• Status: Published
• Publication Date: 18-Nov-2021
• ICS: 23.100.10 - Pumps and motors
• Technical Committee: ISO/TC 131/SC 8 - Product testing
• Drafting Committee: ISO/TC 131/SC 8/WG 14 - Testing of water hydraulic pumps
• Current Stage: 6060 - International Standard published
• Start Date: 19-Nov-2021
• Due Date: 06-Feb-2022
• Completion Date: 19-Nov-2021

Overview

ISO 23840:2021 - Water hydraulics - Water-hydraulic pumps - Methods of testing and representing basic steady-state performance defines standardized methods to measure and present the steady‑state performance and efficiency of water‑hydraulic positive displacement pumps with continuously rotating shafts. The standard covers required test equipment, a prescribed test circuit, preparation and measurement procedures, and rules for presenting test results for pump performance testing using tap water as the working fluid.

Key topics and requirements

• Scope: Tests apply to water‑hydraulic positive displacement pumps; results include performance and efficiency under steady‑state conditions.
• Test fluid: Tap water only; no additives. Filtration to 10 μm is required before the hydraulic tank.
• Test circuit: A specified circuit (Figure 1) including pump under test, torque meter, tachometer, boost pump, relief valves, flowmeter and heat exchanger. Installation rules address tank height (above pump suction) and prevention/removal of air entrainment.
• Measurements required: Effective torque, rotational frequency (n), flow rate (q), inlet and outlet gauge pressures (pi, pe), and water temperature (Tw).
• Temperature control: Tests carried out at stated temperature measured at tank or pump inlet; recommended range 20 °C to 40 °C. Temperature accuracy classes A/B/C correspond to tolerances ±1.0 °C / ±2.0 °C / ±4.0 °C (see Annex A).
• Test procedure: Detailed preparation (start‑up, leak and vibration checks, pressurization sequence) and measurement steps covering the full working rotational frequency and outlet pressure ranges. Steady‑state readings must be within permissible variation (Annex B).
• Results presentation: Requirements for expressing performance, volumetric and hydromechanical efficiencies, derived capacity and torque, and example graphical formats (Annex C).

Applications and who uses it

• Pump manufacturers - to certify and publish consistent performance data for water‑hydraulic pumps.
• Test laboratories - to build compliant test rigs and produce repeatable, accredited test reports.
• System designers & integrators - to select pumps and size components in clean applications (food, packaging, semiconductors, cosmetics, animal/plant systems).
• Procurement & compliance teams - to compare suppliers using standardized performance metrics.
• R&D and QA - to validate design changes, efficiency improvements and quality control using standardized steady‑state tests.

Related standards

• ISO 4391 - Hydraulic fluid power - Pumps, motors and integral transmissions - Parameter definitions and letter symbols.
• ISO 5598 - Fluid power systems and components - Vocabulary.

Keywords: ISO 23840:2021, water hydraulics, water‑hydraulic pumps, pump testing, steady‑state performance, pump efficiency, flow rate, test procedure, positive displacement pumps.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 23840
First edition
2021-11
Water hydraulics — Water-hydraulic
pumps — Methods of testing and
representing basic steady-state
performance
Hydraulique à l'eau — Pompes hydrauliques avec de l'eau —
Méthodes d'essai et représentation des performances de base en
régime permanent
Reference number
© ISO 2021
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
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or ISO’s member body in the country of the requester.
ISO copyright office
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Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and units. 2
5 Water . 2
6 Tests . 2
6.1 Requirements . 2
6.1.1 General . 2
6.1.2 Installation of the unit under test . 3
6.1.3 Test fluid . 3
6.1.4 Temperature . 3
6.2 Test circuit . 3
6.3 Test measurement . 4
6.4 Preparation of test . 5
6.5 Measurement procedure . 5
7 Expression of results . 6
Annex A (informative) Errors and classes of measurement accuracy . 7
Annex B (normative) Permissible variation of mean indicated values of controlled
parameters . 9
Annex C (informative) Example of graphs presenting test results .10
Bibliography .14
iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
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electrotechnical standardization.
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described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
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www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 131, Fluid power systems, Subcommittee
SC 8, Product testing.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
Introduction
Water hydraulics or water-hydraulic systems (hydraulic systems in which water is used as the power-
transmitting medium in a fluid power system) have potential market demand as they facilitate
maintaining cleanness and permit a reduction in fluid cost, machine size and fire risk. Applications
of water hydraulics have been expanding into new fields which require cleanness, most notably the
cleaning sector, animals and plants, food, packaging, cosmetics and semiconductors, amongst others.
This is due to the environmental cleanliness of water compared with alternative hydraulic fluids, such
as oil.
Although water hydraulics is a generally well-known concept, there are currently no International
Standards specialized in water hydraulics. As the technology of water hydraulics is an emerging
technology, it is considered a relevant topic for international standardization by related countries,
including both developing countries as well as developed ones, and in particular by ISO/TC 131 (Fluid
power systems), in order to accelerate the development of this technology.
The water-hydraulic pump is one of the key components of water hydraulics. The development of an
appropriate International Standard for water-hydraulic pumps, which focuses on methods of testing
and representing basic steady state performance, is therefore critical to business trade and/or product
acceptance by consumers.
v
INTERNATIONAL STANDARD ISO 23840:2021(E)
Water hydraulics — Water-hydraulic pumps — Methods of
testing and representing basic steady-state performance
1 Scope
This document specifies methods for determining the performance and the efficiency of water-
hydraulic positive displacement pumps having continuously rotating shafts. This document provides
test equipment, a test procedure under steady-state conditions and the presentation of test results.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 4391, Hydraulic fluid power — Pumps, motors and integral transmissions — Parameter definitions and
letter symbols
ISO 5598, Fluid power systems and components — Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 4391 and ISO 5598 and the
following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
water-hydraulic pump
positive displacement pump that transforms mechanical energy into water-hydraulic energy with
water as the system fluid
3.2
flow rate of the pump under test
flow rate measured at the outlet port of the pump under test
3.3
pump volumetric efficiency
ratio of the effective output flow rate to the derived output flow rate
3.4
hydromechanical pump efficiency
ratio of the derived torque to the effective torque
3.5
inlet gauge pressure of the pump under test
measured gauge pressure at or near the suction port of the pump under test
Note 1 to entry: The value of “inlet gauge pressure of the pump under test” shows either positive or negative.
3.6
outlet gauge pressure of the pump under test
measured gauge pressure at or near the delivery port of the pump under test
3.7
tap water
water supplied through pipes or tubes to taps/faucets
3.8
total dissolved solids
TDS
weight of inorganic and organic matter in true solution per unit volume of water
4 Symbols and units
For the purposes of this document, the symbols and units listed in Table 1 apply. In Table 1, as the unit
3 -1 3
of derived capacity and shaft speed, m and s , as well as m /rev and rev/s, may be used.
Table 1 — Symbols and units
Description Symbols Unit
n
Rotational frequency rev/s
p
Inlet gauge pressure of the pump under test Pa
ei,
Outlet gauge pressure of the pump under test p Pa
eo,
q
Flow rate of the pump under test m /s
p
Water temperature T K
w
Effective torque t N·m
e
Derived capacity V m /rev
i
Pump overall efficiency η -
t
Hydromechanical pump efficiency η -
m
Pump volumetric efficiency η -
v
5 Water
Tap water can be used for the working fluid of water-hydraulic systems including a water-hydraulic
pump.
6 Tests
6.1 Requirements
6.1.1 General
Installations shall be designed to prevent air entrainment during operation and measures shall be
taken to remove free air from the system before testing.
The tank height level should be designed to be higher than the pump suction port, in order to prevent
the reduction of the suction pressure.
Tap water shall be supplied through a filter with the specified filtration performance (10 microns) to a
hydraulic tank.
Figure 1 illustrates the basic circuit for the test of a water-hydraulic pump. This figure does not
incorporate all the safety devices necessary to protect against damage in the event of any component
fracture or fragmentation. Those who are responsible for carrying out the test shall give due
consideration to safeguarding both personnel and equipment.
6.1.2 Installation of the unit under test
The test circuit shall be constructed in accordance with Figure 1.
6.1.3 Test fluid
Working fluid of water hydraulics shall be tap water. Additives shall not be added to the test fluid.
6.1.4 Temperature
Tests shall be carried out at a stated test fluid temperature. The test fluid temperature shall be measured
in a tank or at the pump inlet. The position of the temperature measurement shall be determined by
the manufacturer and user of the pump under test. Water temperature shall be controlled by a heat
exchanger within the range recommended by the manufacturer. Measurements shall be made at
temperature levels between 20 °C and 40 °C.
The test fluid temperature shall be maintained within the limits stated in Table 2. The temperature
tolerance (either A, B, or C) shall be recorded.
Table 2 — Indicated test fluid temperature tolerance
Temperature accuracy class (see Annex A) A B C
Temperature tolerance (°C) ±1,0 ±2,0 ±4,0
6.2 Test circuit
The test circuit shown in Figure 1 shall be used.
The first shut-off valve (Key 14 of
...