LEYBOLD ScrewLine SP250 User manual

P/N
115 001
115 003 ATEX 3i
115 006
SCREWLINE SP 250
Dry Compressing Screw Vacuum Pump
Operating Instructions GA02412_002_C0

Contents
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Page
0 Important Safety Information 5
Explanation of Warning Symbols 5
0.1 Mechanical Hazards 7
0.2 Electrical Hazards 8
0.3 Thermal Hazards 9
0.4 Hazards Caused by Materials and Substances 9
0.5 Ignition Risk 11
0.6 Noise Hazard 11
0.7 Risk of Pump Damage 12
SP 250 ATEX Category 3i (inside) Vacuum Pump 14
Classification and Marking of the Pump 14
Areas of Application 15
Safety Measures 18
1 Description 20
1.1 Design and Function 20
1.2 Technical Data 23
1.2.1 Technical Data of the SP-Guard Monitoring System 24
1.2.2 Technical Data of the Solenoid Gas Ballast Valve 24
1.2.3 Technical Data of the Purge Gas Facility 25
1.3 Supplied Equipment 27
1.4 Built-in Accessories 28
1.5 Accessories 30
1.6 Wearing Parts and Original Spare Parts 30
2 Transport and Storing 31
2.1 Pumps with Castors 32
2.2 Storing the Pump 32
3 Installation 33
3.1 Placement 33
3.1.1 Floor 33
3.1.2 Air Cooling and Pump Covers 33
3.1.3 Ambient Conditions 34
3.2 Conforming Utilisation 34
3.3 Connection to the System 35
3.3.1 Connections at the Intake Side 36
3.3.2 Connections at the Delivery Side (Exhaust 36
3.4 Electrical Connection 37
3.4.1 Motor Protection 37
3.4.2 Star/Delta Start-up Circuit 38
3.4.3 Soft Start 38
3.4.4 Mains Connection 38
3.4.5 Power Failure 42
3.4.6 Operation with a Frequency Converter (FC Operation) 42

Contents
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These Operating Instructions are the original instructions.
3.5 Oil Temperature Sensor Pt 100 43
3.6 Connecting the SP-Guard 45
3.7 Retrofitting the Manual Gas Ballast with a 24 V DC Valve 48
3.7.1 Connecting the Electro-pneumatic Gas Ballast Valve 49
3.8 Connecting the Purge Gas Valve 50
4 Operation 51
4.1 Start-up 51
4.1.1 Oil Filling for the Gear 51
4.1.2 Switching the Pump On 53
4.2 Operation 54
4.2.1 Operation with SP-Guard 54
4.2.2 Gas Ballast Operation 55
4.2.3 Purge Gas Operation 56
4.2.4 Regular Checks 57
4.3 Switching Off/Shutting Down 58
5 Maintenance 59
5.1 Checking the Oil Level 60
5.1.1 Oil Change and Oil Filter Change 60
5.2 Cleaning the Oil Cooler 62
5.3 Draining Out Condensate 63
5.4 Cleaning the Dust Filter in the Intake Line 63
5.5 Checking and Cleaning the Gas Ballast Filter 64
5.6 Replacing the Throttle in the Purge Gas Device 64
5.7 Service at Leybold 66
5.8 Maintenance Schedule 67
6 Troubleshooting 68
7 Waste Disposal 71
EC Declaration of Conformity 72

Safety Information
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Obligation to Provide Information
Before installing and commissioning the pump, carefully read these
Operating Instructions and follow the information so as to ensure optimum
and safe working right from the start.
The Leybold SCREWLINE SP 250 have been designed for safe and efficient
operation when used properly and in accordance with these Operating
Instructions. It is the responsibility of the user to carefully read and strictly
observe all safety precautions described in this Section and throughout the
Operating Instructions. The pump must only be operated in the proper
condition and under the conditions described in the Operating
Instructions. It must be operated and maintained by trained personnel only.
Also consult local, state, and national agencies regarding specific require-
ments and regulations. Address any further safety, operation and/or mainte-
nance questions to our nearest office.
DANGER indicates an imminently hazardous situation which, if not avoid-
ed, will result in death or serious injury.
WARNING indicates a potentially hazardous situation which, if not avoided,
could result in death or serious injury.
CAUTION indicates a potentially hazardous situation which, if not avoided,
could result in minor or moderate injury.
NOTICE is used to notify users of installation, operation, programming or
maintenance information that is important, but not hazard related.
We reserve the right to alter the design or any data given in these Operating
Instructions. The illustrations are not binding.
Retain the Operating Instructions for further use.
In order to avoid the destruction of systems and injury to operating personnel
we urgently recommend to observe the information and installation informa-
tion provided in these Operating Instructions.
NOTICE
DANGER
WARNING
CAUTION
NOTICE

Safety Information
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0 Important Safety Information
Explanation of Warning Symbols
Hazardous voltage
Disconnect power before opening.
Contact causes electrical shock.
Hot surface
Do not touch.
Allow this area to cool before servicing
Burn hazard
Hot surface inside. Do not touch.
Wear protective equipment.
Reactive or corrosive media
Reactive or corrosive gases may cause health problems .
When the pump has been used to pump reactive or corrosive gases
before, introduce corresponding safety precautions before opening it,
e.g. wear gloves, breathing protection or protection clothing
Toxic gases
must not be pumped with this pump.
Danger of explosion
Explosive gases and vapours
must not be pumped with this pump.
Fire danger
Combustible gases and vapours,
gas mixtures with an oxygen share exceeding 21% and
pyrophorous (self-igniting) substances
must not be pumped with this pump.

Safety Information
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Purge gas
Check compatibility with applications.
Overpressure in the discharge line
Components can be thrown in all directions.
The pressure in the discharge line must not exceed atmospheric
pressure by 200 mbar max.
The discharge line must not be blocked or restricted
Pumps with wheels
must only be placed and moved on levelled horizontal surfaces!
Rotating parts
When operating the pump with open intake port, there is the risk of
suffering injury by rotating parts.
Never operate the pump with open intake port or fan cover, except
from checking the direction of rotation.
Vacuum
Avoid exposing any part of the human body to the vacuum.
Machinery starts automatically
Connect the pump so that it not will restart automatically after a mains
power failure, once the power returns.
Overhead load
Transport the pump only at the two crane eyes or with a forklift
secured on a suitable palette.

Safety Information
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0.1 Mechanical Hazards
1 When operated with an open intake flange, there exists a risk of suffer-
ing injury by rotating parts. Do not operate the pump with an open
intake flange or fan cover except when checking the direction of rota-
tion.
2 Avoid exposing any part of the human body to the vacuum.
3 The pump is intended for generating a vacuum only. If an overpressure
can occur in the system then the pump must be protected against
such an overpressure by an overpressure safety valve, for example.
4 We recommend to always operate the pump with a silencer or a con-
nected discharge line. The pressure in the discharge line must not
exceed atmospheric pressure by 200 mbar max.
Make sure that the gas flow at the discharge is not blocked or restrict-
ed in any way, even when the pumped out gases need to be collected
or contained.
The discharge line must not be blocked or restricted. Before commis-
sioning the pump, open all shutoff devices or valves in the discharge
line.
In the case of processes involving much condensate, we recommend
the installation of a condensate separator in the discharge line.
5 Select the location where the pump is installed so that all controls can
be easily accessed. Deposit the pump only on a floor which is level. It
can topple when it is tilted by more than 10° with respect to the verti-
cal axis. When the pump is filled with oil an angle exceeding 2° is not
permissible.
For pumps on castors only
Because of the fitted castors, the pump must only be placed on a level
floor capable of supporting the pump’s weight, as otherwise there
exists the risk of the pump rolling away. Moreover, the pump may only
be moved on a level floor! Moving the pump along sloping paths or
ramps is prohibited! The pump must only be transported with a forklift
or a crane! At the installation location, secure against rolling away.
6 For transporting the pump use only approved transport means. When
selecting the lifting and transport means take note of the total weight
before transporting the pump. As standard, the pump has been
equipped with two crane eyes. When transporting the pump with a
forklift or alike, ensure that the pump has been secured on the
supplied or a suitable palette.
The crane eyes of the screw pump must never be used to lift any
pump combinations (Roots pump + backing pump).
CAUTION

Safety Information
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7 Before beginning with any maintenance and servicing work always
ensure that no gas can flow backwards through the pump since then
the rotors might turn against the normal direction of rotation. For this
reason vent the vacuum chamber to the exhaust pressure level or
ensure through suitable valves that the vacuum chamber and the lines
are reliably separated from the pump. When connecting several pump
systems, pressure differences between inlet and discharge can give
rise to uncontrolled turning of the pump’s shafts.
8 Lay the electric feed lines so that there is no risk of tripping over these.
9 The warning information on the pump must not be covered.
10 When changing the oil remove any escaped oil as otherwise there is
the risk of slipping.
0.2 Electrical Hazards
1 The electrical connection must only be provided by a trained person.
Please observe the national regulations in the country of use like
EN50110-1 for Europe, for example.
2 Lay the connecting lines so that they cannot be damaged. Protect the
lines against humidity and contact with water. Avoid thermally stressing
the lines due to unfavourable laying.
3 Note the information on the type of protection.
4 The pump must only be operated at the frequency specified for the
motor even when operated off a frequency converter.
When using frequency converters you must ensure an effective protec-
tion against overspeeding.
5 Always operate the pump with a properly connected protective earth
conductor.
6 The pump must be integrated within the system controller such that
the pump can not run up automatically when the pump has been shut
down before due to an overloaded motor.
This equally applies to any emergency shutdowns. After having
removed the fault cause, the pump must be switched on manually
again.
7 Before starting with any maintenance or servicing work reliably discon-
nect the pump from all sources of power (lockout/tagout).
8 High electric voltages! When touching parts at high electric voltages,
there is the risk of suffering severe injuries by an electric shock! Covers
marked with this symbol must only be opened by trained electricians
after having reliably deenergised (lockout/tagout) the equipment.
9 Observe the manufacturer’s information and the Operating Instructions
for the respective frequency converter.
10 After having connected the motor and each time after having made
changes to the wiring, check the direction of rotation. If the direction of
rotation is wrong, the pressure can increase on the intake side.
Moreover, the pump can suffer severe damage.
DANGER

Safety Information
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0.3 Thermal Hazards
1 With the pump warm from operation, the housing and oil temperature
may exceed 70 °C. Protect hot parts against being touched. Let pump
and oil cool down. Always wear protective gloves and protective gog-
gles, also for protection against aggressive residues in the oil.
2 Handle the pump only while vented and after having let it cool down.
3 Take note of the warning information on the housing surface. If this
warning information was removed, covered or obstructed, then pro-
vide corresponding additional warning information.
4 Never open the oil fill or oil drain plugs while the pump is running.
There is the risk of suffering burns.
0.4 Hazards Caused by Materials and Substances
1 The pump is not suited for pumping of:
■combustible and explosive gases and vapours (except within the
permissible scope for pumps certified in accordance with ATEX
Category 3 inside)
■radioactive and toxic substances
■gas mixtures with an oxygen share exceeding 21%
■pyrophorous (self-igniting) substances.
Moreover, the pumps are not suited for placement and operation
within explosion hazard areas.
Please consult us first when planning such an application.
2 Before commissioning the pump, make sure that the media which are
to be pumped are compatible with each other so as to avoid hazar-
dous situations. All relevant safety standards and regulations must be
observed.
3 Before operating the pump with a gas ballast or a purge gas (option)
check the compatibility of the gas with the pumped media so as to
avoid dangerous conditions during operation.
4 Pump with installed purge gas unit:
When operating the pump with a purge gas valve, secure the purge
gas supply so that in the event of a malfunction no overpressure can
occur in the system.
5 When nitrogen is used as the purge gas or as the gas ballast, small
quantities of nitrogen can escape to the surroundings. Ensure sufficient
ventilation for the room in which to pump has been installed.
6 The vacuum line must be leaktight. Reactive or corrosive process
gases may escape or the pumped gases can react with air or atmos-
pheric humidity. After installation of the pump and after servicing work
on the vacuum, a leak search will always be necessary.
Please note the special information on the pump’s shaft seal given in
the following.
CAUTION
DANGER

Safety Information
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7 Shaft seal of the pump
Shaft seals are present only on the discharge side of the pump’s
rotors. The two shaft seals are non-contacting owing to a combination
of piston ring and labyrinth seals, but are not hermetically tight. The
seal in the direction of the atmospheric side and in the direction of the
gear chamber is vented.
In the case of a low pressure in the discharge line there is the risk of
adding small quantities of air via the shaft seal to the process gas.
When the discharge pressure on the process gas side exceeds atmos-
pheric pressure, small quantities of processed gas can escape into the
gear housing and also to the outside.
In order to prevent any process gas from escaping from the pump
chamber, use purge gas for the shaft seal. The purge gas will reliably
prevent any leaks between the gas chamber and the surroundings
provided the correct quantity of purge gas is used within the specified
limits.
Please consult us first when planning such an application.
8 When the pump has been used to pump harmful media before, intro-
duce corresponding safety precautions before opening the intake or
the discharge connections. Before opening the pump, purge it for a
longer period of time with an inert gas. If necessary, wear gloves,
breathing protection or protection clothing and work under a fume
hood. Firmly seal off the pump. When shipping the decontaminated
pump for servicing please also indicate the type of hazard. For this see
Section 5.7 Service at Leybold.
When shipping contaminated pumps which require approval by the
authorities, note the applicable regulations regarding packaging and
shipping.
9 In special cases the composition of these substances may be relevant
to safety. In these cases, the user must carefully review the effect of
these substances and introduce suitable personnel protection meas-
ures.
You must also expect the gas to have a different composition at the
inlet compared to the discharge. This must be included in the assess-
ment of potential hazards.
10 In case of a malfunctioning pump, in particular because of a blocked
discharge line or seized rotors due to hard deposits or foreign objects,
the possibility of leaks in the casing cannot be ruled out. When pump-
ing harmful gases, the operator must ensure that such a malfunction
cannot occur, respectively that leaks at the pump will not be a hazard.

Safety Information
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11 Leybold is not in a position to perform servicing (repairs) and waste
disposal of radioactively contaminated pumps. Both needs to be
ensured from the side of the user.
12 When disposing the pump, used lubricants and used oil filters observe
the applicable environment regulations.
0.5 Ignition Risk
The pump is not suited for operation within explosion hazard areas.
Please consult us first when planning such an operation.
0.6 Noise Hazard
The noise level of the pump during ultimate pressure operation with
silencer or connected discharge line corresponds to the values stated
in the Technical Data. In other operating modes and with other equip-
ment or with several pumps at the same location, higher values must
be expected.
We recommend to wear hearing protectors (earmuffs).
DANGER
CAUTION

Safety Information
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0.7 Risk of Pump Damage
1 With the pump filled with oil it must placed such that it will deviate by
no more than 2° from the vertical axis as otherwise oil can enter into
the sealing system. Before filling the pump with oil, align it.
Transporting the pump filled with oil is not permissible.
2 Always use the intake screen which has been fitted as standard and
clean it regularly. The intake screen serves to protect the pump. Small
items (screws, welding beads, pieces of wire, etc.) which during instal-
lation work inadvertently fall into the intake line or are sucked in, are
retained by the intake screen.
The intake screen does not replace a filter. Prevent the intake of parti-
cles from the side of the process by fitting suitable filters. Upstream fil-
ters protect the pump against damage to the pump chamber.
3 When pumping dust containing media, install a dust filter in the pro-
cess gas flow upstream with respect to the pump.
4 When connecting the pump, provide a suitable valve on the intake side
for the purpose of shutting off the intake line so as to prevent the
pump from turning backwards in the event of a power failure.
Otherwise the pump may suffer damage or oil may contaminate the
pump chamber by reverse venting via the shaft seals.
5 Lines and other vacuum connections should be clean and free of oil.
Special attention must be paid here when oil-sealed pumps have been
used on the vacuum side. Check the conditions before initial commis-
sioning. In the case of deviations, the pump can suffer contamination
with oil residues.
6 The pressure within a pump which has been switched off will increase
to ambient pressure within a few seconds. In such a case the pump is
vented through the discharge and the shaft seal drain. We recommend
to fit a nonreturn discharge valve so as to prevent the pump from turn-
ing backwards.
7 The discharge line should be laid so that it slopes down and away
from the pump so as to prevent condensed vapours from backstream-
ing into the pump.
8 In the case of wet processes we recommend the installation of liquid
separators, upstream and downstream of the pump so as to avoid the
influx of liquid into the pump.
9 During installation work on the intake and discharge lines do not sub-
ject flanges to any stresses. Check the rubber elements of the pump’s
feet as to any deformation.
10 Protect the electric motor against being overloaded:
For proper connection, a suitable motor protection switch must be
used. Set this motor protection switch in agreement with the informa-
tion provided on the motor nameplate.
Connect the pump to the correct mains voltage and mains frequency.
NOTICE

Safety Information
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11 The pump’s motor is equipped with an overtemperature protection
(PTC). Processing the PTC signal is a safety measure which in the
case of inadequate cooling, a temporary mains power phase failure or
in the case of frequency variations offers effective protection preventing
costly damage to the motor coils.
12 The pump must only be operated with all covers in place so that ade-
quate cooling of the pump is ensured.
13 If corrosive or reactive gases at low concentrations are being pumped,
then operate the pump with purge gas. Consult us first as to which
pumps are required for specific processes and applications.
14 Before pumping condensable vapours the pump should be at ope-
rating temperature. If a gas ballast is present, then it should be
opened. The pump will attain its operating temperature approximately
30 minutes after having started the pump. During this warm-up phase,
the pump should be left separated from the process by a valve in the
intake line, for example.
15 With the pump warm from operation do not clean it from the outside
with water. There is the risk of a rotor crash due to shock cooling.
16 If condensable vapours have been pumped, the pump should before
switching off be purged with an inert gas or air (depending on the spe-
cific application) for approximately 15 minutes. This process should
also be run before cleaning the pump chamber.
17 For shutting down the pump purge the pump before switching off with
an inert gas or air (depending on the specific application) for approxi-
mately 15 minutes. Place desiccant onto the intake screen in the
intake flange and into the discharge flange and blank off the flanges
with a piece of foil. Disconnect the pump from the mains power. When
storing the pump for a longer period of time, drain out the oil first.
Package the pump airtight in polyethylene foil.
18 Improper maintenance or repair work can have an influence on the
service life and the performance of the pump and will void any warran-
ty claims.
Pressures given in bar or mbar are absolute values. If exceptionally a gauge
pressure is meant, a “g” is added (bar(g) = bar (gauge) = bar overpressure)

ATEX
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SP 250 ATEX Category 3i (inside) Vacuum Pump
Classification and Marking of the Pump
The SP 250 ATEX Category 3i (inside) fulfils for the inside, i.e. the process
gas side of the pump, the fundamental safety requirements of the EC
Directive 94/9/EG. The pump is marked as follows:
II (inside) 3GD II T160 °C X (10 °C < Ta < 40 °C)
These pumps are not suited for placement (installation) in explosion hazard
areas.
Key to the Symbols
II Equipment group II applies to all equipment in areas which are potentially
endangered by an atmosphere capable of exploding, except in under-
ground mining operations and their above ground facilities which may be
endangered by mine gas and/or combustible types of dust.
(inside)/(outside)
Specifies the category/conditions according to which the inside (i) (i.e.
parts of the equipment in contact with the process gas flow) and the out-
side (o) of the equipment are classified, provided there is a difference bet-
ween them.
3Category 3 comprises equipment which is so designed that it can be ope-
rated in agreement with the characteristic quantities (operating parameters)
specified by the manufacturer ensuring a normal degree of protection.
Equipment belonging to this category is intended for operation in areas
where it not needs to be expected that an explosive atmosphere occurs
due to gases, vapours, mists or raising dust, but when it occurs, then with
all probability only rarely and briefly.
Equipment belonging to this category ensures during normal operation the
necessary degree of safety.
GFor areas with an atmosphere capable of exploding caused by gases,
vapours or mists in the air.
DFor areas with an atmosphere capable of exploding caused by explosive
dusts.
II, IIA, IIB or IIC
Explosion groups: these are subdivisions for equipment belonging to Group
II, which are used in connection with some protection types. This subdivisi-
on is based on the maximum experimental safe gap and the minimum igni-
tion current of the explosive atmosphere. See EN 60079-0.).
Equipment marked with IIB is also suited for applications which require
equipment marked with IIA.
Equipment marked with IIC is also suited for applications which require
equipment belonging to explosion group IIA or IIB.
Equipment without indication of the explosion group may be used in explo-
sive atmospheres of explosion groups IIA, IIB and IIC.
For Part Number 115 003

ATEX
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T3, T4
Temperature class: classification of equipment within classes depending on
their maximum surface temperature corresponding to the table given
below:
Temperature class Maximum surface
temperature (°C)
T1 450
T2 300
T3 200
T3 (160 °C) 160
T4 135
T5 100
T6 85
The temperature class and the actual maximum surface temperature of the
equipment includes a safety margin with respect to the minimum ignition
temperature of the potentially explosive atmosphere as demanded by EN
13463-1.
Ta Permissible ambient temperature for operating the pump
10 °C < Ta < 40 °C.
XSpecial operating conditions need to be complied with!
The special conditions and information provided in the Operating
Instructions apply.
Modifying the supplied pump, voids the CE and ATEX Declaration of
Conformity.
Related Accessories
When using accessory components together with the pump it needs to be
ensured that these accessories are suited for operation in explosion hazard
areas.
Operation in the Pump System
When operating the screw pump in a pump system, different ATEX catego-
ries or temperature classes may apply. You must ensure that the operating
parameters comply with the stated technical data. You must run an ignition
hazard assessment for the entire pump system.
Areas of Application
The inside (process gas side) of this vacuum pump is so rated and designed
that the occurrence of foreseeable ignition sources can be excluded during
normal operation. Provided the pump is operated in accordance with the
parameters specified in the Operating Instructions the pump will offer a nor-
mal degree of protection. For this reason it is suited for operation under con-
ditions where it is unlikely that an atmosphere capable of exploding is created
by gases, dusts, vapours or mists in the air or if such atmospheres do occur
then this only rarely and only briefly (i.e. Zone 2).

ATEX
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The pump itself must not be installed and operated in explosion hazard
areas.
Areas in which explosive atmospheres (gases, dusts, vapours or mists) can
occur in the air are subdivided into three zones corresponding to the frequen-
cy and duration of occurrence of an explosive atmosphere. These zones are
designated as 0, 1 and 2.
The definitions for these zones are described in Annex I of the “Atex Directive
(Directive 99/92/EG) for improving the safety and health protection of workers
potentially at risk from explosive atmospheres”.
Information as to the classification of the areas with explosive atmospheres in
the 3 Zones, is provided in the Directive 99/92/EG and the corresponding
guide (COM (2003) 515) together with the European standard EN 60079-10
(Electrical apparatus for explosive gas atmospheres - Part 10: Classification
of hazardous areas). Additionally, further information on the avoidance of
explosions and on the topic of explosion protection can be found in the
Directive 99/92/EG and the corresponding guide.
This information can be downloaded from the EC Internet site.
Gas Composition
It is important to note that the composition of the gas at the intake on the
suction side of the pump and at the discharge to the atmosphere may pos-
sibly differ. This may possibly have an influence on the zone assignments (EG
Directive 99/92/EG).
Ignition Temperatures of Gases/Vapours
The pumps are suited only for applications in which potentially explosive gas
and vapour mixtures exhibit an ignition temperature of over 160 °C.
The ignition temperatures (sometimes also called self ignition temperature) of
gases and vapours can be taken from the material safety data sheets.
The pump is not suited for operation in potentially explosive gas mixtures in
which the oxygen concentration exceeds 21% or if reactive, aggressive or
corrosive gases are present.
Ignition Temperatures of Dusts
In accordance with Directive 99/92/EG, the system operator is committed to
provide a hazard assessment. For this reason the minimum glow point tem-
perature and the minimum ignition temperature of the dust must be known to
him.
Two calculations for determining two limit temperatures must be performed:
a) Limit temperature 1 = 2/3of the minimum ignition temperature
b) Limit temperature 2 = minimum glow point temperature* less 75 K
DANGER

ATEX
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From these two calculated limit temperatures it will now be necessary to take
into account the value which guarantees the higher degree of safety.
*The value for the glow temperature applies to a dust thickness of 5 mm. In
the case of even thicker dust deposits, the temperature safety margin should
be increased even further.
Potential Ignition Sources
An assessment of the ignition risk was performed in accordance with the
European standard EN 13463-1 (EN 13463-1 Non-electrical equipment for
potentially explosive atmospheres. Part 1: Basic method and requirements).
Based on this assessment the ignition sources listed in the following were
determined which may occur during operation of the pump:
Potential ignition sources Remarks
Hot surfaces inside and outside due to process gas inlet
temperature and gas compression
Hot gases, adiabatic Hot gases from the process which are being
compression pumped, temperature increase owing to gas
compression within the pump.
Hot gases are ejected at the exhaust.
Mechanical sparks Will not occur during normal operation
Electrical sparks Outside of the pump due to motor,
accessories
Static electricity Will not occur during normal operation
Chemical reactions Will not occur during normal operation
Special Requirements for Safe Usage “X”
Conforming utilisation of this pump demands the connection of, and opera-
tion with purge gas for Category 3 (inside),
For particle, respectively dust filters, the use of a mesh of 40 µm max. will be
mandatory in connection with ATEX applications so as to ensure the safe
operation.
If dusts occur, then an approved dust filter must be used and must be elec-
trically connected to ground correspondingly.
The pump must exclusively be filled and operated with the oil LVO 210 as the
operating agent. The use of any other kind of oil may result in increased sur-
face temperatures and cause severe damage to the pump.
During normal operation, the oil temperature must not exceed 70° C. A regu-
lar check will be necessary, see also Chapter 3.5 Oil Temperature.
The pump must be installed such that oil sight glass and SP-Guard are easily
visible and cannot be damaged. The oil level must be checked regularly.

ATEX
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The pump must be installed so that only minimal quantities of dust can depo-
sit themselves on the surfaces. In those cases where dust deposits form,
measures must be introduced to remove these a regular basis.
The pumps must only be operated at an ambient temperature ranging bet-
ween 10 °C and 40 °C.
The maximum gas admission temperature must not exceed 100 °C.
The maximum overpressure at the gas inlet must not exceed pamb + 55 mbar.
The maximum exhaust back pressure must not exceed pamb + 200 mbar.
Safety Measures
Hot Surfaces
Compression of the gases will during normal operation of the vacuum pump
cause it to heat up resulting in hot surfaces. Tests have shown that during
conforming operation of the pump (in accordance with these Operating
Instructions) the process gas path which might come into contact with a
potentially explosive atmosphere, attains during operation at a nominal fre-
quency of 50 Hz or 60 Hz a maximum temperature below 160 °C.
The maximum temperatures are attained during constant operation at an inlet
pressure below 300 mbar (absolute). The actually attained temperature
depends on the inlet pressure.
Hot Gases
Due to compression of the gases, the pump will produce during normal ope-
ration hot exhaust gases. The exhaust gas temperatures will not exceed the
stated maximum surface temperatures of the pump. The exhaust gases need
to be discharged through a suitable exhaust gas system.
Mechanical Sparks
During normal operation no mechanically generated sparks are created.
The intake of particles into the pump must be prevented so as to prevent the
formation of hot spots due to friction.
Electric Sparks
These can be caused by the electric motor and the accessories supplied
with the pump. Where the outside of the pump has been certified then motor
and supplied accessories have the same classification. Follow the
manufacturer’s information.

ATEX
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Static Electricity
The pump must be connected with a low impedance to ground so as to
avoid charging with static electricity. This is attained by properly connecting
the protective ground conductor at the point provided for it. During normal
operation no dangerous creation of charges will occur.
In connection with ATEX usage, the electrically conducting link between all
pump chamber cover, exhaust flange and gear housing is absolutely manda-
tory! After any assembly work on the pump chamber, this link must be
checked. For this, use a resistance meter and measure the resistance of the
link which must be less than 100 Ohm.
A filter on the intake side must be connected to ground in accordance with
the Operating Instructions of the filter.
Use only the original spare parts from Leybold.
Ground Connection
Between the M 8 tapped blind hole on the pump (see figure) and the frame
ground/ground rail of the frequency converter, an EMC compliant ground
connection (copper strap, for example) must be provided.
Chemical Reactions
The pump shall not come in to contact and shall not be used in connection
with reactive or corrosive gases which may cause an exothermal chemical
reaction.
Additional Safety Measures
Overheating of the pump can give rise to temperatures which exceed the
certified maximum surface temperature.
Compliance with the operating parameters stated in these Operating
Instructions must be ensured.
Run checks on a regular basis and comply with the maintenance schedule.
Additional Maintenance Requirements
In those cases where dust may deposit itself on the pump or the motor sur-
faces, measures must be introduced which ensure that such deposits are
removed on a regular basis.
In order to ensure that the defined level of safety is maintained, only accesso-
ry parts and wearing parts from Leybold must be used.
Connect ground strap here!

Description
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1 Description
1.1 Design and Function
The SCREWLINE SP 250 is a dry compressing screw-type vacuum pump
capable of a maximum pumping speed of 270 m3· h-1 at 50 Hz and
330 m3· h-1 at 60Hz.
It has been developed specifically for the special requirements of industrial
applications. Thus the ruggedness of the pump was a main design criterion.
The screw shaped rotors are fitted to two horizontally arranged shafts and
revolve without making contact within the pump chamber. The shafts are
synchronised by a toothed gear. The shafts are driven via a further gear stage
by an electric motor.
In vacuum pumps, the seals and the bearings on the vacuum side are always
a potential source for a breakdown. On the one hand lubricants may enter
from the bearing into the vacuum process and on the other hand aggressive
process media can endanger the bearings.
These disadvantages are avoided by the “cantilevered” arrangement of the
rotors. The SP 250 is equipped with two cantilevered screw type rotors
which are guided by oversized shafts and bearings. The bearings are located
both in the gear chamber of the pump.
A further advantage of the cantilevered arrangement is that the pump cham-
ber is easily accessible without having to disassemble any bearings. Thus any
possibly required cleaning operations necessary due to the influence of the
process can be run easily.
The cantilevered rotors minimise the risk of bearing damage and also reduce
on-site maintenance to a minimum.
Shaft seals are in the case of the SP 250 pump only required on the delivery
side of the rotors. Owing to the small pressure difference between discharge
and gear, simple and reliable seals can be provided. The two shaft seals con-
sist of a combination of a piston ring and a labyrinth seal thus making almost
no contact so that the seals will be almost free of wear.
In standard applications no purge gas will be required at the seals. However,
if demanded by the process conditions, a purge gas may be supplied to the
seals. In the case of ATEX applications operation with purge gas is an abso-
lute requirement.
The SP 250 is air-cooled, a radial fan supports the cooling effect for the hou-
sing which is equipped liberally with cooling fins.
Depending on requirements, the screw pumps may be combined with Roots
pumps so as to attain higher pumping speeds at lower pressures.
Screw rotors
Cantilevered bearing
Shaft seal
Purge gas
Cooling