The Danfoss range of PAHT high-pressure pumps
is specically designed for use with technical
water such as:
• Ultra-pure water that has undergone
multiple reverse osmosis processes
• De-ionized water
• Demineralized water
Danfoss PAHT pumps are positive displacement
pumps, with axial pistons that move a xed
amount of water in each cycle. Flow is proportional to the number of input shaft revolutions
(rpm). Unlike centrifugal pumps, they produce
the same ow at a given speed independently of
no matter what the discharge pressure.
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Data sheet PAHT 2-308 pumps
Below sectional drawing is an example of a PAHT pump.
1: Mounting ange
2: Shaft seal
3: Connecting ange
4: Port plate
5: Valve plate
6: Retainer plate
7: Swash plate
8: End cap
9: Spring
10: Pis ton
11: Cylinder barrel
12: Housing with bearing
2. Benets• Zero risk of lubricant contamination:
- Oil lubricants are replaced with the
pumped medium, water, so there is no
contamination risk from the pump.
• Low maintenance costs:
- Ecient design and all-stainless steel
construction ensure exceptionally long
lifetime. When Danfoss specications
are met, service intervals of up to 8,000
hours can be expected. Service is easy,
and can be carried out on site due to
the simple design and few parts.
• Low energy costs:
- The highly ecient axial piston design
provides the lowest energy consumption of any comparable pump on the
market.
• Easy installation:
- The lightest and most compact design
available.
3. Application examples• High-pressure cleaning with ultra-pure
water, as used in the manufacturing of
at-panel displays and many other
electronic products.
• High-pressure cleaning with ultra-pure
water, as used in the manufacturing of
parts for the automobile industry.
• Adiabatic cooling systems to replace or
supplement standard A/C systems in server
rooms and factories.
- Pump can be installed horizontally or
vertically.
- No pulsation dampeners necessary due
to extremely low-pressure pulsation.
- Powered by electric motors or combustion engines.
- Suitable for both boosted inlet
pressure and water supply from a tank.
- No need for cooling circuits due to very
high mechanical eciency.
• Certied quality:
- Fullls the stringent hygiene requirements, VDI 6022, HACCP.
- Certicates:
ISO 9001, ISO 14001
API available on request
• Humidication in oce buildings, elec-
tronic component manufacturing, dairies,
greenhouses, etc.
• Dust suppression and odor control
systems, for example in paper, textile and
wood production.
• Reduction of NOx emissions in diesel
engines and gas turbines.
• Gas turbine by inlet fogging and fuel wash
systems.
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Data sheet PAHT 2-308 pumps
4. Technical data4.1 PAHT 2-12.5
Pump size23.246.31012 .5
Code number PAHT180B0 031180B0077180B0030180B0029180B0032180B0033
7. InstallationSee the gure below for instructions on how to
mount the pump and connect it to an electric
motor or combustion engine.
ACB
A: Pump
B: Bell housing
C: Coupling
D: Motor
D
If alternative mounting is required, please
contact your Danfoss sales representative for
further information.
Note: Do not add any axial or radial loads to the
pump shaft.
7.1 Filtration
Proper ltration is crucial for the performance,
maintenance and warranty of your pump.
Protect your pump, and the application in which
it is installed, by always ensuring that ltration
specications are met, and by always changing
lter cartridges according to schedule.
Since water has very low viscosity, Danfoss PAHT
pumps have been designed with very narrow
clearances in order to control internal leakage
rates and improve component performance. To
minimize wear on the pump, it is therefore
essential to lter inlet water properly.
The main lter must have a ltration eciency
of 99.98% at 10 μm. We strongly recommend
that you always use precision depth lter
cartridges rated 10 μm abs. β
Please note that we do not recommend bag
lters or string-wound lter cartridges, which
typically have only 50% ltration eciency. This
means that out of 100,000 particles that enter
such lters, 50,000 particles pass right through
them; compare this to precision depth lters that
are 99.98% ecient, and only allow 20 of the
same 100,000 particles to pass through.
≥ 5,000.
10
For more information on the importance of
proper ltration, including explanation of
ltration principles, denitions, and guidance on
how to select the right lter for your pump,
please consult our Filtration information and
specications (Danfoss document number
521B1009).
7.2 Noise
Since the pump unit is mounted on a frame, the
overall noise level can only be determined for a
complete system. To minimize vibrations and
noise throughout the system, it is therefore very
important to mount the pump unit correctly on a
frame with dampers and to use exible hoses
rather than metal pipes where possible.
The noise level is inuenced by:
• Pump speed:
High rpm makes more uid/structureborne pulsations/vibrations than low rpm.
• Discharge pressure:
High pressures make more noise than low
pressures.
• Pump mounting:
Rigid mounting makes more noise than
exible mounting because of the structureborne vibrations. Be sure to use dampers
when mounting.
• Connections to pump:
Pipes connected directly to the pump make
more noise than exible hoses because of
structure-borne vibrations.
• Variable frequency drives (VFDs):
Motors regulated by VFDs can produce
more noise if the VFD does not have the
right settings.
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Data sheet PAHT 2-308 pumps
7.3 Open-system design
A Inlet line:
Dimension the inlet line to obtain minimum pressure loss (large ow, minimum
pipe length, minimum number of bends/
connections, ttings with small pressure
losses and restrictions).
B Inlet lter:
Install the inlet lter (1) in front of the PAHT
pump (2). Please consult the Danfoss lter
data sheet for guidance on how to select
the right lter.
C Monitoring pressure switch:
Install the monitoring pressure switch (3)
between the lter and the pump inlet. Set
the minimum inlet pressure according to
specications described in item 4, technical
data. The monitoring pressure switch stops
the pump if inlet pressure is lower than the
set minimum pressure.
D Monitoring temperature switch:
Install the monitoring temperature switch
(4) between the lter and the pump, on
either side of the monitoring pressure
switch. Set the temperature value according to technical data, item 4. The monitoring temperature switch stops the pump if
inlet temperature is higher than the set
value.
E Hoses:
Always use exible hoses (5) to minimize
vibrations and noise.
F Inlet pressure:
In order to eliminate the risk of cavitation
and other pump damage, pump inlet
pressure must be maintained according to
specications described in item 4, technical
data.
G Non-return valve (6):
Should be installed after the outlet to
prevent pump backspin, which may ruin
the pump.
H Pressure relief valve:
As the Danfoss PAHT pump begins to
create pressure and ow immediately after
start-up regardless of any counter pressure,
a pressure relief valve (7) should be
installed to prevent system damage.
Note: If a non-return valve is mounted in the
inlet line, a low-pressure relief valve is also
recommended between the non-return valve
(8) and the pump to protect against high-pressure peaks.
14556
PI
8
M
2
PI
SYSTEM
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Data sheet PAHT 2-308 pumps
PI
System
PI
M
1
2
3
4
55
7
6
7.4 Closed-system design (not applicable
for PAHT 256-308)
A Inlet line:
Dimension the inlet line to obtain minimum pressure loss (large ow, minimum
pipe length, minimum number of bends/
connections, ttings with small pressure
losses and restrictions).
B Inlet lter:
Install the lter (1) in front of the tank (2).
Please consult the Danfoss lter data sheet
for guidance on how to select the right
lter.
C Monitoring pressure switch:
Install the monitoring pressure switch (3) in
front of the lter (1). Set the maximum inlet
pressure to 2 barg (29.0 psig). The monitoring pressure switch will stop the pump (5) if
inlet pressure is higher than 2 barg (29.0
psig), indicating that the lter element
must be changed.
D Monitoring temperature switch:
Install the monitoring temperature switch
(4) in the tank. Set the temperature value
according to technical data, item 4. The
monitoring temperature stops the pump if
inlet temperature is higher than the set
value.
E Hoses:
Always use exible hoses (6) to minimize
vibrations and noise.
F Inlet pressure:
In order to eliminate the risk of cavitation
and other pump damage, pump inlet
pressure must be maintained according to
specications described in item 4, technical
data.
G Non-return valve (7):
Should be installed after the outlet to
prevent pump backspin, which may ruin
the pump.
H Pressure relief valve:
As the Danfoss PAHT pump begins to
create pressure and ow immediately after
start-up regardless of any counter pressure,
a pressure relief valve (8) should be
installed to prevent system damage.
I System water lling:
To ensure proper ltration of new water
(10) supplied to the system, always use the
lling valve (9).
J Minimum level switch:
Install the minimum level switch (11) above
the outlet of the reservoir. The level switch
must stop the pump if the water in the
reservoir is below the switch, which
indicates that the reservoir is empty.
2
11
Reservoir
4
M
667
PI
5
PI
System
9
1
3
10
8
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Data sheet PAHT 2-308 pumps
8. Dimensions and
connections
8.1 PAHT 2-6.3
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Data sheet PAHT 2-308 pumps
8.2 PAHT 10-12.5
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Data sheet PAHT 2-308 pumps
8.3 PAHT 20-32
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Data sheet PAHT 2-308 pumps
8.4 PAHT 50-90
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Data sheet PAHT 2-308 pumps
8.5 PAHT 256-308
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Data sheet PAHT 2-308 pumps
9. ServiceDanfoss PAHT pumps are designed for long
periods of service-free operation to ensure low
maintenance and life cycle costs. Provided that
the pump is installed and operated according to
Danfoss specications, Danfoss PAHT pumps
typically run 8,000 hours between service.
However, the service schedule for your Danfoss
PAHT pump may vary according to the application and other factors.
The life of a pump may be greatly shortened if
Danfoss recommendations concerning system
design and operation are not followed.
In our experience, poor ltration is the number
one cause of pump damage.
Other factors that aect pump performance and
lifetime include:
• running the pump at speeds outside
specications
• supplying the pump with water at temperatures higher than recommended
• running the pump at inlet pressures
outside specications
• running the pump at outlet pressures
outside the specications.
We recommend that you inspect your pump
after 8,000 hours of operation even if it is
running without any noticeable problems.
Replace any worn parts if necessary, including
pistons and shaft seals, to keep your pump
running eciently and to prevent breakdown. If
worn parts are not replaced, then our guidelines
recommend more frequent inspection.
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Data sheet PAHT 2-308 pumps
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Danfoss A/S
High Pressure Pumps
DK-6430 Nordborg
Denmark
Danfoss ca n accept no respons ibility for pos sible errors in ca talogues, bro chures and other pr inted material. Da nfoss reserves t he right to alter its p roducts with out notice.
This also a pplies to produc ts already on ord er provided that su ch alterations ca n be made without su bsequential cha nges being nece ssary in speci cations alread y agreed.
All trade marks in this mate rial are proper ty of the respec tive companies . Danfoss and the Dan foss logotyp e are trademark s of Danfoss A/S. Al l rights reserv ed.