Palas VKL 10 User manual

PALAS GmbH
Partikel- und Lasermesstechnik
Greschbachstrasse 3b
76229 Karlsruhe
Phone [phone]
Fax [phone]
[email protected]
www.palas.de
Operation Manual
Dilution System
VKL 10 and VKL 100

OPERATION MANUAL VKL 10 /100
VERSION V005-06-2020
2
Content
Important Note !!!................................................................................................................................... 4
1. Delivery................................................................................................................................................ 5
1.1. Delivery Check......................................................................................................................... 5
2. Safety conditions / Intended use .................................................................................................... 6
2.1. General safty conditions.......................................................................................................... 6
2.2. Intended use............................................................................................................................ 6
2.3. Responsibility of the operator................................................................................................. 6
3. Initial Operation .............................................................................................................................. 7
3.1 Initial operation and short instruction .......................................................................................... 7
4. Operating Principle.............................................................................................................................. 8
4.1. General Information..................................................................................................................... 8
4.2. The Inlet System and the Mixing Chamber .................................................................................. 9
4.3. The Dilution Factor..................................................................................................................... 10
4.4. The Outlet Nozzle and Isokinetic Conditions ............................................................................. 10
5. Equipment Layout ............................................................................................................................. 11
5.1. The Pneumatic System............................................................................................................... 11
5.2. Components and their Function................................................................................................. 12
5.3. The Calibration Certificate.......................................................................................................... 14
6. Operation .......................................................................................................................................... 15
6.1. Installation.................................................................................................................................. 15
6.1.1. Installation as Single Unit.................................................................................................... 15
6.1.2. Cascading of Two or More Units ......................................................................................... 16
6.2. Selecting Appropriate Outlet Nozzles ........................................................................................ 18
6.3. Setting of Pre-pressure............................................................................................................... 19
6.4. Impact of Pressure and Temperature ........................................................................................ 20
6.4.1. Pressure Impact................................................................................................................... 20
6.4.2. Temperature Impact............................................................................................................ 20
7. Cleaning............................................................................................................................................. 21
7.1 General Information.................................................................................................................... 21
7.1.1 Cleaning of the Inlet Nozzle.................................................................................................. 21
7.1.2. Cleaning of the Outlet Nozzle .............................................................................................. 21
7.1.3. Cleaning of the Mixing Chamber......................................................................................... 22
7.2. Filter Control and Filter Change ................................................................................................. 23

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7.2.1. Filter Control........................................................................................................................ 23
7.2.2 Filter Change......................................................................................................................... 23
8. Maintenance ..................................................................................................................................... 24
9. Troubleshooting ................................................................................................................................ 27
10. Problems –what to do if the dilution system of the series VKL does not work correctly:............. 28
10.1 Pollution of the dilution system ............................................................................................ 28
10.2 FAQs ...................................................................................................................................... 28
10.3 General.................................................................................................................................. 28
11. Technical Data ................................................................................................................................. 29
12. Spare parts list / accessories list...................................................................................................... 30
13 Transport, packaging and storage............................................................................................. 30
13.1 Packaging:.................................................................................................................................. 30
13.2 Storage: ..................................................................................................................................... 30
13.3 Transport:.................................................................................................................................. 30
14. Disposal of the VKL dilution systems............................................................................................... 31
15. Literature......................................................................................................................................... 31
16. Feedback form................................................................................................................................. 32

OPERATION MANUAL VKL 10 /100
VERSION V005-06-2020
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Important Note !!!
It is important to read the operating instructions thoroughly before operating the dilution
system !
The manufacturer will not be liable for damages caused by incorrect handling, operating or
cleaning.
Please observe the following points:

Operation of equipment should only take place in dry rooms, under ambient
atmospheric pressure, and at room temperature. If operation under different
conditions becomes necessary, you should contact the manufacturer prior to starting
operation.

The manufacturer will not be liable for defects resulting from improper operation,
if operation takes place under different environmental conditions, such as corrosive
or explosive environment, strong electric or electromagnetic fields, within areas of
ionizing radiation, within areas prone to shock or vibration.

If the dilution system is used with humid and sticky aerosols it needs to be
checked for dirt more frequently (especially for plugging of the inlet nozzle).

Do not suck in any aerosols that react aggressively to brass, to anodized aluminum,
or to stainless steel.

Only use original spare parts.
Attention: Aerosols might be dangerous to your health. That’s why they ought not to be
inhaled. It might also be necessary to wear protective clothes. Please pay attention to the
correspondent standards and safety rules.

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VERSION V005-06-2020
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1. Delivery
1.1. Delivery Check
Please verify immediately after unpacking of equipment, if delivery is complete. Besides the
dilution stage itself, the following items must be part of the delivery:
1 suction nozzle
4 transport covers (yellow plastic parts, installed at the equipment)
1 box spanner, size 14 mm (nut)
1 tube connector for the excess aerosol outlet (black plastic part).
Fig.: 1.1 VKL 10

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VERSION V005-06-2020
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2. Safety conditions / Intended use
2.1. General safty conditions
•For safety reasons, under no circumstances may the machine be commissioned if there is
visible damage.
In this event, please contact Palas® (Tel.: [phone]).
•The dilution system has been set by the manufacturer to be used with a maximum pre-
pressure of Pmax 8 bar for the compressed air supply. Please make sure that the
maximum pre-pressure of Pmax 8 bar specified on the type plate agrees with the
provided compressed air line where the machine is to be used.
•Only use original spare parts! Please contact the manufacturer whenever necessary.
•Please only use dry, particle- and oil-free compressed air supply.
2.2. Intended use
•The dilution system of the series VKL was designed to dilute a high concentrated aerosol
by the ejector principle with dry, oil- and particle free compressed air.
•The manufacturer is not responsible for any damage, which arease due to incorrect
operation, cleaning, error in operation or the measurement of aerosols which gas
conditions or compound the instrument is not specified for.
•The machine may only be operated in dry rooms, under atmospheric ambient pressure
and at room temperature.
Operating under other ambient conditions such as in corrosive or explosive
environments, in strong electric or electromagnetic fields, in areas with ionising radiation
as well as in areas subject to impact and vibration is not covered by any functional
guarantee by the manufacturer
2.3. Responsibility of the operator
•The device was designed and built in consideration of the standards to be adhered to. It
therefore represents state-of-the-art technology and allows a high degree of safety in
operation.
•Please only operate the dilution systems of the VKL series after reading carefully the
manual.
•Shall be operated by trained personal only.
•Be sure that the machine shall not be used by unauthorised personnel.
•Caution: Depending on the type, aerosols can pose a health hazard. They should
therefore not be inhaled. When working with or when around hazardous materials, care
must also be taken to wear appropriate protective clothing (respirator mask). Please
follow all applicable guidelines and accident prevention regulations.

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3. Initial Operation
3.1 Initial operation and short instruction
remove all four transport covers; keep them and re-install them after experiment is done.
position dilution system inbetween dust or aerosol take-out and measuring instrument
connect inlet nozzle to sampling probe
connect measuring instrument to outlet nozzle
make sure that excess air is drawn away.
No counterpressure may be produced at the excess air outlet.
toggle switch in position "off"
connect compressed air supply (4 - 8 bar) (fast coupling NG 8)
turn pre-pressure control counterclockwise first, until it arrests (lift locking ring)
switch on dilution stage
set desired pre-pressure by turning pre-pressure control clockwise
start measuring instrument and procedure
WARNING
Escaping aerosols can be toxic and pose a health hazard.
Residual air flows out of the device via the exhaust air outlet.
If hazardous aerosols are used and the exhaust air outlet is open,
these aerosols can get into the environment and harm persons.
►If hazardous aerosols are used: Verify that the exhaust air outlet is
connected to a suitable filter or cleaning system via the exhaust air
tube connector.

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VERSION V005-06-2020
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4. Operating Principle
4.1. General Information
The purpose of a dilution system is, first of all, to lower the concentration of a given aerosol
while leaving the particle size distribution of the aerosol unchanged. In using the dilution
system VKL, this aim is reached by homogeneously mixing a definite amount of clean air with
a definite amount of aerosol. The ratio of amount of aerosol and clean air is predetermined
and stable. The external clean air flows through an ejector-nozzle system. This causes an
underpressure which sucks in the aerosol. Consequently, the dilution stage is a self-sucking
system.
One single dilution stage VKL 10 has a dilution factor of 10. If a higher dilution factor is
required, several units may be connected in series. Such a cascade connection permits for
example the dilution of 2 liters of aerosol with only 72 liters of clean air by a factor of
10,000.
The dilution factor of the VKL 100 depends on the volume flow rate of particle-free air and
varies between 150 and 90. A dilution factor of 100 is achieved in one unit with the same
clean air consumption compared to two VKL 10.
However, the application range of the VKL 100 is limited compared to the one of the
VKL 10:
- highly concentrated dusts with mass concentration > 100 mg/m3and
particle size > 2 µm may block the capillary tube
- liquid particles with a diameter > 1 µm may break up due to shear forces in the flow
- the dilution factor depends on the clean air flow

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4.2. The Inlet System and the Mixing Chamber
The details given in the following chapter only apply to VKL 10!
Figure 4.1. shows a cross-section of the dilution stage. Particle-free air with a volume flow
rate Vrdetermined by the pre-pressure P, flows through an annular slit around the inlet
nozzle. The resulting under-pressure dP0causes the aerosol which is to be diluted, to be
sucked in and to be mixed homogeneously with clean air in the mixing chamber. If the clean
air flow rate is increased, the flow speed within the annular nozzle increases
correspondingly. This causes according to Bernoulli (s. below) the under-pressure dP0at the
inlet nozzle to increase, and the flow rate Van increases, too. Both flow rates are connected
through the underpressure, and equally depend on it. Consequently, the ratio of the flow
rates remains constant for different pre-pressures, P.
Bernoulli formula:
dP = 1/2 * rho * v²
dP: pressure drop at a nozzle (here: under-pressure)
rho: gas density
v: gas velocity through the nozzle
excess airoutlet excessair
tubeconnector
outlet nozzle
dP 0
mixingchamber
annularnozzle
inlet nozzle
Vin Vout
Vrcompressed air
with pre-pressure P
Fig. 4.1.: Cross section of dilution stage

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4.3. The Dilution Factor
The dilution factor W describes the ratio between the total volume flow rate Vges and the
inlet volume flow rate Van:
W = Vges / Van
with:
Vges = Vr+ Van
(Vr: clean air flow rate)
The enclosed publication describes this equation in more detail. It demonstrates in theory
and practice that the dilution ratio remains constant, independently of the pre-pressure,
within a large range. The equations 1 - 4 and diagram 4 describe the correlations.
4.4. The Outlet Nozzle and Isokinetic Conditions
Since most particle measuring instruments have a sampling flow rate that is lower than the
flow rate of the diluted aerosol, a portion Vab of this flow has to be taken out of the mixing
chamber for the measurement. This is done via the outlet nozzle. When taking a portion of
the flow you must see to it that isokinetic conditions prevail. Isokinetic conditions are given,
if, at the suction location, the flow velocity inside the nozzle corresponds to the velocity
inside the flow channel. Different nozzle diameters permit the adaptation of different outlet
flow rates to different total flow rates. Following the isokinetic sampling of a part of the
flow, the remaining air flows to the outside via the excess air outlet. For aerosols, for
example, which constitute a danger to health, the excess air has to be led away via a tube. It
is absolutely necessary not to produce any counter-pressure during this process, because an
increase of the pressure POinside the mixing chamber would influence the inlet flow rate
and thus the dilution ratio. See also equations 5 - 6 and diagram 5 of the publication.