ISO 3529-2:2020
(Main)Vacuum technology — Vocabulary — Part 2: Vacuum pumps and related terms
Vacuum technology — Vocabulary — Part 2: Vacuum pumps and related terms
This document gives definitions of vacuum pumps and related terms. It is a continuation of ISO 3529‑1 which defines general terms used in vacuum technology.
Technique du vide — Vocabulaire — Partie 2: Pompes à vide et termes associés
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Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 3529-2
Second edition
2020-02
Vacuum technology — Vocabulary —
Part 2:
Vacuum pumps and related terms
Technique du vide — Vocabulaire —
Partie 2: Pompes à vide et termes associés
Reference number
ISO 3529-2:2020(E)
©
ISO 2020
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ISO 3529-2:2020(E)
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ISO 3529-2:2020(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
3.1 Vacuum pumps . 1
3.2 Parts of vacuum pumps . 7
3.3 Accessories . 9
3.4 Categories of vacuum pumps with reference to operation .10
3.5 Characteristics of vacuum pumps.11
Annex A (informative) Classification table of vacuum pumps .14
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ISO 3529-2:2020(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
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ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
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
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
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expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 112, Vacuum technology.
This second edition cancels and replaces the first edition (ISO 3529-2:1981), which has been technically
revised. The main changes compared to the previous edition are as follows:
— under positive displacement pumps are added diaphragm-, peristaltic-, scroll-, screw-, claw- and
trochoid vacuum pumps;
— under kinetic vacuum pumps are added regenerative- and compound turbo vacuum pump;
— under gas entrapment or capture vacuum pumps different types of condensers are added;
— under parts, categories and characteristics of vacuum pumps are added some new actual used
definitions.
A list of all parts in the ISO 3529 series can be found on the ISO website.
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.
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INTERNATIONAL STANDARD ISO 3529-2:2020(E)
Vacuum technology — Vocabulary —
Part 2:
Vacuum pumps and related terms
1 Scope
This document gives definitions of vacuum pumps and related terms. It is a continuation of ISO 3529-1
which defines general terms used in vacuum technology.
2 Normative references
ISO 3529-1:2019, Vacuum technology — Vocabulary — Part 1: General terms
ISO 21360-1:2012, Vacuum technology — Standard methods for measuring vacuum-pump performance —
Part 1: General description
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1 Vacuum pumps
3.1.1
vacuum pump
device for creating, improving and/or maintaining a vacuum
Note 1 to entry: Two basically distinct categories may be considered: gas transfer pumps (3.1.2) and gas gathering
vacuum pumps (3.1.32)
Note 2 to entry: Some definitions given in ISO 3529-1 are repeated in this document in deferent terms to adapt to
vacuum pumps.
Note 3 to entry: Vacuum is defined in ISO 3529-1.
Note 4 to entry: A classification table for vacuum pumps is described in Annex A.
3.1.2
gas transfer vacuum pumps
vacuum pump (3.1.1) that transports gas molecules from the inlet to the outlet (3.2.3) of the vacuum
pump by means of positive displacement or transfer of kinetic momentum
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ISO 3529-2:2020(E)
3.1.3
positive displacement vacuum pump
vacuum pump (3.1.1) in which a volume filled with gas is cyclically isolated from the inlet, the gas being
then transferred to an outlet (3.2.3)
Note 1 to entry: In most types of positive displacement vacuum pumps the gas is compressed before exhausted.
Two categories can be considered: reciprocating or oscillating positive displacement vacuum pumps (3.1.4–
3.1.6) and rotary positive displacement vacuum pumps with single (3.1.7–3.1.13) or double (3.1.14–3.1.16) rotor
principle.
Note 2 to entry: Positive displacement vacuum pump are often equipped with a gas ballast system, to admit a
controlled quantity of a suitable non-condensable gas during the compression part of the cycle so as to reduce or
avoid the extent of condensation within the vacuum pump.
Note 3 to entry: An oil-sealed (liquid-sealed) vacuum pump is a rotary positive displacement vacuum pump in
which oil (liquid) is used to seal the gap between parts which move with respect to one another and to reduce the
residual free volume in the pump chamber at the end of the compression part of the cycle.
Note 4 to entry: A dry positive displacement vacuum pump is a device, where the pumping chambers are not oil-
sealed (liquid-sealed).
Note 5 to entry: All types of positive displacement vacuum pumps can be combined as multi-stages of the same
or differing.
3.1.4
diaphragm vacuum pump
dry positive displacement vacuum pump (3.1.3) in which the gas is compressed and expelled due to the
movement of a reciprocating or oscillating action of a diaphragm by using suitable valves
3.1.5
piston vacuum pump
positive displacement vacuum pump (3.1.3) in which the gas is compressed and expelled due to the
movement of a reciprocating piston moving in a cylinder by using suitable valves
3.1.6
linear peristaltic vacuum pump
vacuum pump (3.1.1) which uses linear placed actuators forcing or compress the gas through a
flexible tube
3.1.7
scroll vacuum pump
vacuum pump (3.1.1) which uses two interleaving circular involute spirals to compress gases before
exhausted
Note 1 to entry: Depending on the application scroll pump may or may not have an inlet valve, isolation valve for
fault conditions or power losses.
3.1.8
rotary vane vacuum pump
rotary positive displacement vacuum pump (3.1.3) in which an eccentrically placed rotor is turning
tangentially to the fixed surface of the stator
Note 1 to entry: The swept compressed gas is expelled to atmosphere via a discharge valve.
Note 2 to entry: Two or more vanes sliding in slots of the rotor (usually radial) and sliding along on the internal
wall of the stator, divide the stator chamber into several parts of varying volume.
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ISO 3529-2:2020(E)
3.1.9
liquid ring vacuum pump
rotary positive displacement vacuum pump (3.1.3) in which an eccentric rotor with fixed blades throws
a liquid against the stator wall
Note 1 to entry: The liquid takes the form of a ring concentric to the stator and combines with the rotor blades to
define a varying volume.
3.1.10
external vane vacuum pump
rotary positive displacement vacuum pump (3.1.3) in which a rotor is turning eccentrically, in contact
with the internal wall of the stator
Note 1 to entry: A device moving relative to the stator is pressed against the rotor and divides the stator chamber
into parts of varying volume (external vane pump).
3.1.11
rotary piston vacuum pump
rotary positive displacement vacuum pump (3.1.3) in which a rotor is turning eccentrically to the internal
wall of the stator
Note 1 to entry: The stator chamber is divided into two parts of varying volume by a bulkhead (piston or plunger)
sealed in the stator (piston bearing) and rigidly fixed to the rotor.
Note 2 to entry: Rotary piston vacuum pump also called rotary plunger vacuum pump.
3.1.12
trochoid vacuum pump
rotary positive displacement vacuum pump (3.1.3) in which an elliptical piston moves around a shaft
eccentrically
Note 1 to entry: The case is in continuous non-contact sealing with the piston. Oil is fed for sealing.
3.1.13
peristaltic vacuum pump
rotary positive displacement vacuum pump (3.1.3) in which a turning rotor compresses with a number of
rollers or lobes a flexible tube and forcing the gas move through the tube
3.1.14
roots vacuum pump
rotary positive displacement vacuum pump (3.1.3) in which two or three lobed rotors, interlocked and
synchronized, rotate in opposite directions moving past each other and the housing wall with a small
clearance and without touching
Note 1 to entry: Roots vacuum pumps are used as primary — also referred to as mechanical booster vacuum
pump — as well as secondary or main vacuum pump.
Note 2 to entry: Roots pumps have per stage no inner compression ratio.
3.1.15
screw vacuum pump
rotary positive displacement vacuum pump (3.1.3) comprises opposing synchronously rotating screws
with various profile design like tapered or variable pitch for an inner compression ratio
Note 1 to entry: The screw vacuum pump could have profile design without inner compression ratio too.
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ISO 3529-2:2020(E)
3.1.16
claw vacuum pump
rotary positive displacement vacuum pump (3.1.3) in which two claw-shaped rotors, interlocked and
synchronized, rotate in opposite directions moving past each other and the housing wall with a small
clearance and without touching
Note 1 to entry: Claw vacuum pumps are designed with one or more compression stages.
3.1.17
kinetic vacuum pump
vacuum pump (3.1.1) in which a gas or gas molecules can be displaced from the pump inlet to the outlet
(3.2.3) either mechanically (rotating it at high speed or by providing an impulse in the direction of flow)
or by the use of another fluid (providing also an impulse in the direction of flow) or using an electrical
potential to displace gas ions
Note 1 to entry: Three categories can be considered: mechanical kinetic pumps (3.1.18–3.1.22), fluid entrainment
pumps (3.1.23–3.1.30) and ion transfer pumps (3.1.31).
3.1.18
turbine vacuum pump
rotary kinetic vacuum pump (3.1.17) in which the transfer of a large amount of gas is obtained by a
rapidly rotating device
Note 1 to entry: The dynamic sealing is obtained without rubbing. The gas flow either may be directed parallel
to the axis of rotation (axial flow vacuum turbine pump) or at right angles to the axis of rotation (radial flow
vacuum turbine pump or centrifugal vacuum pump).
3.1.19
regenerative vacuum pump
rotary kinetic vacuum pump (3.1.17) in which the transfer of gas is obtained by a centrifugal rotor stage,
utilizing the vortex behaviour of the gas in combination with a side channel parallel to the rotor
Note 1 to entry: Regenerative vacuum pumps are designed with one or more gas ring compression stages.
Regenerative vacuum pumps are available with an axially located gas channel and/or radially located gas
channel.
3.1.20
molecular drag vacuum pump
kinetic vacuum pump (3.1.17) in which a momentum is imparted to the gas molecules by contact between
them and the surface of a high-speed rotor, causing them to move towards a channel to the outlet (3.2.3)
of the vacuum pump.
Note 1 to entry: The technical design based on invention from Gaede, Holweck or Siegbahn.
3.1.21
turbo-molecular vacuum pump
molecular drag vacuum pump (3.1.20) in which the rotor is fitted with discs provided with slots or
blades rotating between corresponding discs in the stator
Note 1 to entry: The linear velocity of a peripheral point of the rotor is of the same order of magnitude as the
velocity of the gas molecules. A turbo-molecular vacuum pump operates normally when molecular flow
conditions obtain.
Note 2 to entry: Compound turbo-molecular vacuum pump.
3.1.22
compound turbo-molecular vacuum pump
one shaft high vacuum pump (3.4.6) with compression-stages based on turbo-molecular vacuum pump
design combined with drag stages based on molecular drag vacuum pump design and/or regenerative
pump stages on the fore vacuum side of the vacuum pump
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ISO 3529-2:2020(E)
3.1.23
diffusion vacuum pump
kinetic vacuum pump (3.1.17) in which a low-pressure, high-speed vapour stream provides the
entrainment fluid
Note 1 to entry: The gas molecules diffuse into this stream and are driven to the outlet. The number density of
gas molecules is always low in the stream. A diffusion vacuum pump operates, when molecular flow conditions
of pumped gas obtained, since vapour jets will not be formed unless the mean free path inside the pump is
large enough.
3.1.24
self-purifying diffusion vacuum pump
oil vapour diffusion vacuum pump (3.1.23) in which the volatile impurities of the operating fluid are
prevented from returning to the boiler but are transported towards the outlet (3.2.3) by a special design
3.1.25
fractionating diffusion vacuum pump
multi-stage oil vapour diffusion vacuum pump (3.1.23) in which the lowest pressure stage is supplied
with the more dense, low vapour pressure constituents of the operating fluid, and where the higher-
pressure stages are supplied with the less dense constituents of higher vapour pressure
3.1.26
diffusion-ejector vacuum pump
multi-stage kinetic vacuum pump (3.1.17) in which a stage or stages having the characteristics of
a diffusion vacuum pump (3.1.23) are succeeded by a stage or stages having the characteristics of an
ejector vacuum pump (3.1.27)
3.1.27
ejector vacuum pump
kinetic vacuum pump (3.1.17) based on the pressure decrease due to a Venturi-effect and in which the
gas is entrained in a high-speed stream towards the outlet (3.2.3)
Note 1 to entry: An ejector vacuum pump operates when viscous and intermediate flow conditions of pumped
gas are obtained.
3.1.28
liquid jet vacuum pump
ejector vacuum pump (3.1.27) in which the entrainment fluid is a liquid (usually water)
3.1.29
gas jet vacuum pump
ejector vacuum pump (3.1.27) in which the entrainment fluid is a non-condensable gas
3.1.30
vapour jet vacuum pump
ejector vacuum pump (3.1.27) based on an entrainment vapour (water, mercury or oil vapour)
Note 1 to entry: The entrainment vapour is
...
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