data sheet

Desalination of Seawater 

Place of operation: Mainland Spain 

A decentralized water supply is currently 

and will in the future be one of the options 

in remote areas. When high-efficiency 

equipment is built together with the latest 

technology, low-power consumption can 

be obtained as proven with this 600 m 3 /d 

water maker with less than 2.2 kW/m 3 

power consumption. The pumps are vertically 

mounted onto the electric motors . 


Place of operation: Canary Islands Spain 

The compact design of the APP pumps 

enables new thinking in the design of 

conventional water makers. Here the APP 

pumps are mounted on top of the membrane 

train providing new possibilities for OEMs 

to set new standards in system design. This 

300 m 3 /d ro-skid uses less than 2.3 kW/m 3 

permeate production. 

Danfoss A/S is one of the largest industrial 

companies in Denmark, with net sales of 

around DKK 15 billion. 

We employ more than 18,500 people, and 

6,500 of them work in Denmark in 15 different 

locations. 

Danfoss is an international group and a 

leader in research, development and production 

for a wide spectrum of different 

industries. 


Place of operation: Oil Rigs North Sea 

Long service life combined with ATEX 

approved APP pumps mounted together 

with EX-Proof Zone II motors via stainless 

steel bell housings. The light weight and 

compact design of the APP pumps make it 

cost-effective to maintain and service the 

system, as the pumps can be transported 

between harbour and oil rig with helicopters 

and replaced without any lifting gear or 

special arrangements. 

We produce about 250,000 components 

each day at our 59 factories in 21 countries. 

The Group’s primary aim is to create quality 

of life for our stakeholders and to be a 

leader in refrigeration, heating and motion 

controls. 

Our work is based on our Core Values: Trust, 

Passion for Technology, Reliability, Global 

Perspective with Local Commitment and 

Environmental and Social Responsibility. 

Danfoss A/S 

DK-6430 Nordborg 

Denmark 

Phone: +45 7488 4325 

Telefax: +45 7445 3831 

E-mail: waterpumps@danfoss.com 

www.danfoss.com 

RO-Solutions 

.... setting new standards. 

DKCFN.PB.010.B1.02 / 521B0734 

Produced by Danfoss G1 Communication 04.09.MR.JN.na 

DANFOSS HIGH-PRESSURE 

WATER SOLUTIONS

The Natural Choice 

APP 0.6-1.0 specifications 

Metric measure US measure 

Flow APP 0.6 10 l/min 2.6 GPM 

APP 1.0 17 l/min 4.5 GPM 

Discharge pressure 10 to 80 bar 140-1150 psi 

Inlet pressure Flodded to 7 bar Flodded to 100 psi 

Pump rpm 1) 700-3000 rpm 700-3000 rpm 

Horse power APP 0.6 1.5 kW 2.0 HP 

At 80 bar APP 1.0 2.2 kW 3.2 HP 

Weight 4.4 kg 9.7 lbs 

Inlet port 1 ⁄ 2 ” BSP 1 ⁄ 2 ” BSP 

Outlet port 1 ⁄ 2 ” BSP 1 ⁄ 2 ” BSP 

APP 1.8-2.2 specification 



APP 2.2 35 l/min 9.2 GPM 

Discharge pressure 10 to 80 bar 140-1150 psi 

Inlet pressure Flodded to 7 bar Flodded to 100 psi 

Pump rpm 1) 700-3000 rpm 700-3000 rpm 


At 80 bar APP 2.2 5.5 kW 7.0 HP 

Weight 7.7 kg 17 lbs 

Inlet port 3 ⁄ 4 ” BSP 3 ⁄ 4 ” BSP 

Outlet port 1 ⁄ 2 ” BSP 1 ⁄ 2 ” BSP 

APP 5.1-10.2 specifications: 



APP 6.5 108 l/min 28.1 GPM 

APP 7.2 120 l/min 31.7 GPM 

APP 8.2 136 l/min 35.4 GPM 

APP 10.2 170 l/min 44.9 GPM 

Discharge pressure 10-80 bar 140-1150 psi 

Inlet pressure Flodded to 7 bar Flodded to 7 bar 

Pump rpm 700-1800 rpm 700-1800 rpm 


At 80 bar APP 6.5 15 kW 20 HP 

APP 7.2 18.6 kW 25 HP 

APP 8.2 19 kW 25.5 HP 

APP 10.2 26.7 kW 35.9 HP 

Weight 32 kg 70 lbs 

Inlet port 2) 1 1 ⁄ 2 ” VIC. 1 1 ⁄ 2 ” VIC. 

Outlet port 2) 1 1 ⁄ 2 ” VIC. 1 1 ⁄ 2 ” VIC. 

1) Higher speed available. Please contact the Sales Organisation. 

2) Other types of connections available on request. 

Common material specifications 

• All wetted parts : Superdublex, polymer, ceramic 

• All external parts: Superdublex, 316 SS, plastic 

The Axial Piston Pump (APP) is a positive displacement pump design 

originating from oil hydraulics and subsequently redesigned by 

Danfoss during the last 15 years, to pump tap and seawater. Tens of 

thousands of pumps are in operation worldwide proving the 

pumps to be among the most cost-effective and reliable pumps for 

membrane applications, both as main high-pressure pumps but 

also for recovering energy as reversing pumps (motors) in the reject 

line. The pumps are made in exotic materials incorporating Duplex 

and Superduplex materials as standard. 

Danfoss A/S RO-Solutions offers not only High-Pressure Pumps but 

also Frequency Inverters, Soft Starters, Valves, Pressure Transmitters 

and all kinds of “around-the-pump” accessories, since one of our 

goals is to facilitate supply chain optimisation for our customers. 

If your business is among the below mentioned applications: 

• Seawater Reverse Osmosis 

• Brackish Water Reverse Osmosis 

• Nanofiltration, ultrafiltration, microfiltration 

• Or even pump and measure low-viscosity corrosive fluids 

prefiltered down to 10 micron absolute 

... have a look on our homepage www.nessie.danfoss.com/rosolution 

With APP pumps from Danfoss you get the following 

benefits 

Low energy consumption 

Total efficiencies up to 95 percent – among the most efficient in the 

market. 

Long service life 

Danfoss guarantees service free operation for more than 8,000 

hours thanks to two design features: 

• No oil lubrication: the medium itself lubricates the pump. 

• No need for service on a regular basis: 

the mechanical shaft is the only seal in the pump. 

Corrosion resistance 

All wetted parts of the pump are designed in duplex, super duplex 

stainless steel and polymer, ensuring resistance to corrosive and 

low viscosity fluids, e.g. seawater and brackish water. 

High-pressure operation 

Continuous operation at a discharge pressure between 10 and 80 

bar (145-1160 psi). Higher discharge pressures are available on 

request. 

Wide flow range 

One pump size covers the same flow range as several centrifugal 

pumps, because the flow is a linear function of the speed (rpm). The 

pumps run at speeds between 700 and 3,000 rpm. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Flow (l/min) 

160 

140 

120 

100 

80 

60 

40 

20 

0 

700 

900 

Typical flow curves at 80 bar (1160 psi) 

2500 

2300 

2100 

1900 

1700 

1500 

1300 

1100 

Pump rpm 

APP 10.2 

APP 8.2 

APP 7.2 

APP 6.5 

APP 5.1 

APP 2.2 

APP 1.8 

APP 1.0 

APP 0.6 

2700 

3000 

2900 

40 

35 

30 

25 

20 

15 

10 

5 

0 

Flow (gal/min) 

Low pulsation 

A design featuring up to nine pistons reduces pressure pulsations 

in the discharge line down to 1.5 percent, rendering pulsation 

dampers superflous addition, and reduceing installing cost. 

Compact design 

The most compact pump on the market, giving system builders a 

free hand to design more compact systems. The pump may also be 

directly mounted onto an electrical motor via a bell housing with a 

flexible coupling.

DATA SHEET 

Water Pumps 

APP0.6 - 2.5 

1. General information 

APP0.6, APP1.0, APP1.5, APP1.8, APP2.2 and APP2.5 pumps are designed to supply low viscosity and corrosive fluids under high 

pressure, eg. in seawater reverse osmosis filtration applications and for high pressure salt water pumping. 

The pumps are based on the axial piston principle enabling a very light and compact design, and they are designed so that 

lubrication of the moving parts in the pumps is provided by the fluid itself. No oil lubrication is thus required. 

All parts included in the pumps are designed to provide long service life, i.e. long service life with a constantly high efficiency and 

minimum of service required. 

The pumps are fixed displacement pumps in which the flow is proportional to the number of revolutions of the input shaft and the 

pump displacement, regardless of any counter-pressure. 

1 2 11 3 

6 8 

7 

1: Shaft sealing 

2: Mounting flange 

3: Bleeding plugs 

4: Retaining ring 

5: Piston/shoe 

6: Valve plate 

7: Swash plate 

8: Cylinder barrel 

9: Spring 

10: Port plate 

11: Connecting flange 

12: Housing with bearing 

10 9 

5 

12 

4 

2. Benefits 

• One of the smallest and lightest pumps on the market. 

• Can be powered by a combustion engine provided that a special coupling is used. 

• Generates insignificant pulsations in the pressure line. 

• No preventive maintenance required (no periodic service like e.g. change of lubricant and wearing parts). 

• Long service life. Danfoss guarantees 8000 hours maintenance-free operation. 

• All parts of the pump are made of non corrosive materials eg. Duplex (SAF 2205/EN1.4462) and 

Super-duplex (SAF 2507/EN1.4410) stainless steel and carbon reinforced PEEK. 

• High efficiency. 

521B0850 DKCFN.PD.010.FA2.02 11-2006

3. Technical data 

Code number 180B3001 180B3002 180B3026 180B3003 180B3004 180B3000 

APP pumps APP0.6 APP1.0 APP1.5 APP1.8 APP2.2 APP2.5 

Geometric displacement cm 3 /rpm (in 3 /rpm) 4 (0.24) 6.3 (0.38) 9.3 (0.56) 10 (0.61) 12.5 (0.76) 15.3 (0.93) 

Flow (3000 rpm) m 3 /h (gpm) 0.6 (2.6) 1.0 (4.4) 1.5 (6.6) 1.7 (7.5) 2.1 (9.2) 2.6 (11.4) 

Min. pressure 1) bar (psi) 20 290 20 290 20 290 20 290 20 290 20 290 

Max. pressure, cont. 2) bar (psi) 80 (1160) 80 (1160) 80 (1160) 80 (1160) 80 (1160) 80 (1160) 

Max. pressure, intermittent 3) bar (psi) 100 (1450) 100 (1450) 100 (1450) 100 (1450) 100 (1450) 100 (1450) 

Max. speed cont. 4) rpm 3450 3450 3450 3450 3450 5) 3000 

Min. speed cont. rpm 700 700 700 700 700 700 

Power requirement at 

80 bar and 3000 rpm: 

kW (hp) 1.9 (2.5) 2.9 (3.9) 4.5 (6) 4.8 (6.3) 6.0 (7.9) 7.2 (9.6) 

Weight kg (lb) 5.2 (9.7) 5.2 (9.7) 8,6 (17) 8.6 (17.0) 8.6 (17.0) 8.6 (17) 

1) For lower pressure, please contact Danfoss RO Sales Organization. 4) For speeds above 3000 rpm the pump must be 

2) For higher pressure, please contact Danfoss RO Sales Organzation. boosted at a pressure of 2-5 bar (29.0 - 72.5 psi). 

3) Intermittent pressure is acceptable for less than 10 seconds per minute. 5) For speeds above 3000 rpm, inspect the pump 

after every 4000 hours of operation. 

4. Flow at different rpm 

Using the diagram shown below, it is easy to select the pump which fits the application best if the flow required and the rotation 

speed (rpm) of the pump are known. 

3 

2,5 

APP2.5 

APP2.2 

m 3 /h 

2 

1,5 

1 

0,5 

APP1.8 

APP1.5 

APP1.0 

APP0.6 

0 

500 1000 1500 2000 2500 3000 3500 

Furthermore, this diagram shows that the flow can be changed by changing the rotation speed of the pump. The flow/rpm ratio is 

constant, and the “desired “ flow can be obtained by changing the rotation speed to a corresponding value. Thus, the required rpm 

can be determined as: 

Desired flow × Rated rpm 

Required rpm = 

Rated flow 

5. Power requirements 

Pump model Flow Pressure rpm Calc. factor 

60 bar 70 bar 80 bar 

l/min m 3 /h gpm 870 psi 1015 psi 1160 psi 

rp m 

APP0.6 10.2 0.61 2.69 1.38 kW 1.61 kW 1.84 kW 2840 475.8 

APP0.6 12.3 0.74 3.25 1.66 kW 1.94 kW 2.21 kW 3400 475.8 

APP1.0 16.53 0.99 4.37 2.14 kW 2.49 kW 2.85 kW 2840 474.6 

APP1.0 19.83 1.19 5.24 2.57 kW 2.99 kW 3.42 kW 3400 474.6 

APP1.5 25.11 1.51 6.63 3.21 kW 3.75 kW 4.29 kW 2890 468.6 

APP1.5 30.17 1.81 7.97 3.86 kW 4.51 kW 5.15 kW 3470 468.6 

APP1.8 26.78 1.61 7.07 3.43 kW 4.00 kW 4.57 kW 2890 463.2 

APP1.8 32.18 1.93 8.50 4.12 kW 4.81 kW 5.49 kW 3470 463.2 

APP2.2 33.48 2.01 8.84 4.29 kW 5.00 kW 5.71 kW 2900 468.6 

APP2.2 40.22 2.41 10.63 5.15 kW 6.01 kW 6.87 kW 3480 468.6 

APP2.5 41.94 2.52 11.08 5.07 kW 5.92 kW 6.77 kW 2900 484.8 

The power requirements can be determined using one of the following guiding equations: 

l/min × bar 16.7 × m 3 /h × bar 0.26 × gpm × psi 

Required power = [kW] or [kW] or [kW] 

Calc. factor Calc. factor Calc. factor 

1 hp = 0.75 kW 

1 kW = 1.34 hp 

1 gpm = 3.79 l/min 

1 l/min = 0.26 gpm 

1 m 3 /h = 4.40 gpm 

1 gpm = 0.23 m 3 /h 

DKCFN.PD.010.FA2.02 521B0850

6. Inlet pressure 

Water supply to the pump is either made from a tank placed above the pump or directly from a feed pump. The pressure at the 

pump inlet (I) must be in the range: 0.5 - 5 bar (7.3 - 72.5 psi). 

7. Temperature and corrosion 

7.1 Operation: 

• Fluid temperature: +3°C to +50°C (+37.4°F to 122°F) - dependent on the NaCl concentration 

• Ambient temperature: +3°C to +50°C (+37.4°F to 122°F) 

The chart below illustrates the corrosive resistance of different types of stainless steel related to NaCl concentration and 

temperature. 

All critical parts of the APP water pump is made of SAF 2507. 

If the water pump is operated at high salinity, always flush the water pump with fresh water at operation stop in order to minimise 

the risk of crevice corrosion. 

904L / SAF 2205 

NaCl vs. temperature 

7.2 Storage: 

• Storage temperature: -40°C to +70°C (+37.4°F to 122°F) – provided that the pump is drained of fluid and stored 

”plugged”. 

Antefreeze protection is required at temperatures below 2°C. Danfoss recommends using Dowcal N from Dow Chemical 

Company or Chillsafe mono propylene glycol from Arco Chemical Company. 

8. Noise level 

The chart indicates the noise level in dB(A) measured at a distance of 1 m from the pump in a reverberation room. 

Type 

60 bar (870 psi) 

1500 rpm 

60 bar (870 psi) 

3000 rpm 

80 bar (1160 psi) 

1500 rpm 

80 bar (1160 psi) 

3000 rpm 

APP0.6 70 73 74 77 

APP1.0 73 75 74 77 

APP1.5 75 76 73 77 

APP1.8 75 76 73 77 

APP2.2 75 76 73 77 

APP2.5 76 77 74 78 

Generally, noise will be reduced if speed is reduced and vice versa. Use flexible hoses in order to minimize vibrations and noise. 

Since the pump is typically mounted on a bell housing or frame, the noise level can only be determined for the complete unit 

(system). 

It is therefore very important that the pump is mounted correctly on a frame with dampers to minimize vibrations and noise. 

The noise level is influenced by: 

• The speed of the pump, high rpm create more noise than low rpm 

• Rigid mounting of the pump generates more noise than flexible mounting 

• Pipe mounting direct to the pump increases the noise level compared to a flexible hose 

9. Filtration 

As water has very low viscosity, the APP pumps have been designed with very narrow clearance in order to control internal leakage 

rates and improve component performance. Therefore it is important that the inlet water is filtered properly to minimize the wear of 

the pump. 

The main filter must have a filtration efficiency of 99.98% at 10 µm. We recommend that you use precision depth filter cartridges 

rated 10µm abs. ß10>5000 (equivalent to a filtration efficiency of 99.98%). Bag filters and string wound filter cartridges typically 

have only 90% filtration efficiency. This means that for each 100,000 particles reaching the filter, 10,000 particles pass through it 

compared to only 20 particles in a filter with an efficiency of 99.98%. 

For more information on the importance of proper filtration, please consult our publication “Filtration” (code number 521B0861), 

which also will provide you with an explanation of filtration definitions and a guidance on how to select the right filter. 

521B0850 DKCFN.PD.010.FA2.02 3

10. Dimensions 

10.1 Pump 

Description APP0.6 and APP1.0 APP1.5, APP1.8, APP2.2 and APP2.5 

A Port position, mm (in) 15.9 (0.63) 18.8 (0.74) 

B Port position, mm (in) 15.9 (0.63) 21.0 (0.83) 

C mm (in) Ø 88 (3.5) Ø 105 (4.1) 

D mm (in) 131 (5.2) 166 (6.5) 

E 

Parallel key, DIN 6885, mm (in) 

5 × 5 × 20 

(0.20 × 0.20 × 0.78) 

5 × 5 × 20 

(0.20 × 0.20 × 0.78) 

F Bleeding M6, Hexagon AF = 5 mm M6, Hexagon AF = 5 mm 

I Inlet connection BSP G½”; 15 (0.59) deep BSP G¾”; 15 (0.59) deep 

O Outlet connection BSP G½”; 15 (0.59) deep BSP G½”; 17 (0.67) deep 

Pump mounting flange SAE A 2 SAE A 2 

10.2 Complete unit 

Pump A (mm) B (mm) C (mm) D (mm) E (mm) F (mm) G (mm) H (mm) IEC Electric motor 

APP0.6 200 245 90 140 100 265 100 131 1.5 kW, FPA 90S-2 

APP1.0 200 245 90 140 125 290 100 131 2.2 kW, FPA 90L-2 

APP1.5 250 280 100 160 140 325 120 166 3.0 kW, FPA 100L-2 

APP1.8 250 302 112 190 140 340 120 166 4.0 kW, FPA 112M-2 

APP2.2 300 342 132 216 140 390 144 166 5.5 kW, FPA 132S1-2 

APP2.5 300 342 132 216 178 430 144 166 7.5 kW, FPA 132S2-2 

DKCFN.PD.010.FA2.02 521B0850

11. Installation 

11.1 Mounting 

The figure below illustrates how to mount the pump and connect it to electric motor/combustion engine. 

A: Flexible coupling 

B: Bell housing 

C: Motor shaft 

If alternative mounting is required, please contact Danfoss Sales Organization for further information. 

To ensure easy mounting of the flexible coupling without using tools, the tolerances must be dimensioned accordingly. 

Note: Any axial and/or radial loads on the shaft must be avoided, see “User guide” (521B0888). 

Min. 3 mm 

A 

B 

C 

The pump should be connected to the rest of the plant with a flexible hoses. 

11.2 Open-ended systems with water supply from tank 

In order to eliminate the risk of cavitation, a positive inlet pressure should always be maintained by observing the following 

guidelines: 

1. Place the tank (1) above pump inlet (water level in tank should always be above the pump). 

2. Place a filter (2) in the water supply line in front of the tank. 

3. Dimension the inlet line (3) with minimum pressure drop (large internal diameter, minimum length of pipe, avoid bends and 

fittings with small internal diameter). 

11.3 Open-ended system with direct water supply 

In order to eliminate the risk of cavitation, a positive inlet pressure is always to be maintained at min. 0.5 bar (7.3 psi) and max. 5 bar 

(72.5 psi). 

1. Place the filter (1) in the water supply line in front of the pump. 

2. Place a monitoring pressure switch (2) set at min. 1 bar (14.5 psi) between filter and pump inlet. The monitoring switch must 

stop the pump at pressures lower than 1 bar. (14.5 psi) At speeds above 3000 rpm - use 2 bar (29 psi) as set point. 

521B0850 DKCFN.PD.010.FA2.02 5

11.4 RO system with APP pump 

1. For easy system bleeding and flushing, apply a bypass non-return valve (1) in parallel with the APP pump. 

2. Place an inlet filter (2) in front of the APP pump (3). Please consult section 9, “Filtration” for guidance on how to select the 

right filter. Throughly clean pipes and flush system prior to start-up. 

3. Place a monitoring pressure switch (6) set at min. 1 bar between filter and pump inlet. The monitoring switch must stop the 

pump at pressures lower than 1 bar (14.5 psi). At 3000 rpm - use 2 bar (29 psi) as set point. 

4. Dimension the inlet line to obtain minimum pressure loss (large flow, minimum pipe length, minimum number of bends/ 

connections, and fittings with small pressure losses). 

5. In order to eliminate the risk of damage and cavitation, a positive pressure at the inlet (4) is always to be maintained at min. 

0.5 bar (7.3 psi) and max. 5 bar (72.5 psi). At speeds above 3000 rpm the pressure at the inlet of the water pump must be min. 

2 bar (29 psi). 

6. Use flexible hoses (5) to minimize vibrations and noise. 

7. Install a safety valve (7) in order to avoid system damage as the Danfoss APP pump creates pressure and flow immediately 

after start-up, regardless of any counter-pressure. 

Feed 

2 

5 4 

1 

3 

APP 

5 

7 

Permeate 

6 

M 

Brine 

12. Service 

Provided that the pump has been running according to the Danfoss specifications on pre-filtration, pressure, and rotation speed, 

Danfoss guarantees minimum 8000 hours operation, however max. 18 months from date of sale. 

To prevent a total and disastrous breakdown, Danfoss recommends a pump inspection after max. 8000 hours – at which any worn 

parts must be replaced. 

Note: It is always recommended to replace pistons and shaft sealing if another service-free period is to be obtained. 

If the pistons are not replaced, more frequent inspection is recommended. 

The APP pump is made of duplex/super duplex materials with fine corrosion properties. However, it is always recommended to 

flush the pump when the system is shut down. 

The shaft sealing in the APP pump is made of AISI 316. At high TDS and high water temperature, the service life of the shaft sealing 

will be reduced. For these applications it is recommended to replace the shaft sealing after approx. 4000 hours operation. 

12.1 Periodic maintenance 

Water acts as lubricant in the APP. Thus there is no oil in the pump. 

By operation below the curve for SAF 2507 in the figure in section 7.1, no parts are expected to be replaced within the first 8000 

hours of operation. 

12.2 Repair 

In case of irregular function of the APP, please contact the Danfoss RO Solutions Sales Organisation. 

DKCFN.PD.010.FA2.02 521B0850

DATA SHEET 

Water Pumps 

APP5.1 - 10.2 


APP5.1, APP6.5, APP7.2, APP8.2 and APP10.2 pumps are designed to supply low viscosity and corrosive fluids under high pressure, 

eg. in seawater reverse osmosis filtration applications and for high pressure salt water pumping. 

The APP pumps are based on the axial piston principle enabling a very light and compact design, and they are designed so that 


All parts included in the APP pumps are designed to provide long service life, i.e. long service life with a constantly high efficiency 

and minimum of service required. 


pump displacement, regardless of any counter-pressure. 

1 2 3 4 5 

6 






6: Valve plate 



9: Spring 




7 

8 9 10 

12 

11 

2. Benefits 





• Long service life. Danfoss guarantees 8000 hours maintenance-free operation. 

• All parts of the pump are made of non-corrosive materials eg. duplex (SAF 2205/EN1.4462) and 

superduplex (SAF 2507/EN1.4410) stainless steel and carbon reinforced PEEK. 

• High efficiency. 

521B0851 DKCFN.PD.010.FB1.02 11-2006


Code number 180B3005 180B3006 180B3007 180B3008 180B3010 

APP pumps APP5.1 APP6.5 APP7.2 APP8.2 APP10.2 

Geometric displacement cm 3 /rpm (in 3 /rpm) 50 (3.05) 63 (3.84) 70 (4.27) 80 (4.88) 100 (6.10) 

Flow (1800 rpm) m 3 /h (gpm) 5.1 (22.5) 6.5 (28.6) 7.2 (31.7) 8.2 (36.1) 10.2 (44.9) 

Min. pressure 1) bar (psi) 20 (290) 20 (290) 20 (290) 20 (290) 20 (290) 

Max. pressure, cont. 2) bar (psi) 80 (1160) 80 (1160) 80 (1160) 80 (1160) 80 (1160) 

Max. pressure, intermittent 3) bar (psi) 100 (1450) 100 (1450) 100 (1450) 100 (1450) 100 (1450) 

Max. speed cont. 4) rpm 1800 1800 1800 1800 1800 

Min. speed cont. rpm 700 700 700 700 700 


80 bar and 1800 rpm: 

kW (hp) 13.7 (18.4) 17.3 (23.2) 19.2 (25.7) 21.7 (29.1) 27.4 (36.7) 

Weight kg (lb) 30 (66) 30 (66) 30 (66) 30 (66) 30 (66) 

1) For lower pressure, please contact Danfoss RO Solutions Sales Organization. 

2) For higher pressure, please contact Danfoss RO Solutions Sales Organzation. 

3) Intermittent pressure is acceptable for less than 10 seconds per minute. 

4) For speeds above 1500 rpm the APP pump must be boosted at a pressure of 2-5 bar (29-72.5 psi). 


Using the diagram shown below, it is easy to select the APP pump which fits the application best if the flow required and the 

rotation speed (rpm) of the pump are known. 

m 3 /h 

12,00 

10,00 

8,00 

6,00 

4,00 

APP10.2 

APP8.2 

APP7.2 

APP6.5 

APP5.1 

2,00 

0,00 

600 800 1000 1200 1400 1600 1800 2000 

rp m 






Rated flow 

5. Power requirements 

Pump model Flow Pressure rpm Calc. factor 

60 bar 70 bar 80 bar 

l/min m 3 /h gpm 870 psi 1015 psi 1160 psi 

APP5.1 66 4.0 17.4 8.3 kW 9.7 kW 11.1 kW 1460 475.2 

APP5.1 79 4.7 20.9 10.0 kW 11.7 kW 14.3 kW 1752 475.2 

APP6.5 83 5.0 22.0 10.5 kW 12.3 kW 14.0 kW 1460 475.2 

APP6.5 100 6.0 26.4 12.6 kW 14.7 kW 16.8 kW 1752 475.2 

APP7.2 93 5.6 24.6 11.6 kW 13.5 kW 15.5 kW 1470 480.6 

APP7.2 112 6.7 29.5 13.9 kW 16.3 kW 18.6 kW 1764 480.6 

APP8.2 106 6.4 28.1 12.7 kW 14.8 kW 16.9 kW 1470 502.2 

APP8.2 128 7.7 33.7 15.3 kW 17.8 kW 20.3 kW 1764 502.2 

APP10.2 133 8.0 35.1 16.0 kW 18.7 kW 21.4 kW 1470 496.2 

APP10.2 159 9.6 42.1 19.3 kW 22.5 kW 25.7 kW 1764 496.2 

The power requirements can be determined using one of the following guiding equations: 

l/min × bar 16.7 × m 3 /h × bar 0.26 × gpm × psi 

Required power = [kW] or [kW] or [kW] 

Calc. factor Calc. factor Calc. factor 

1 hp = 0.75 kW 

1 kW = 1.34 hp 

1 gpm = 3.79 l/min 

1 l/min = 0.26 gpm 

1 m 3 /h = 4.40 gpm 

1 gpm = 0.23 m 3 /h 

DKCFN.PD.010.FB1.02 521B0851


Water supply to the APP pump is either made from a tank placed above the pump or directly from a feed pump. The pressure at the 

pump inlet (I) must be in the range: 0.5 - 5 bar (7.3 - 72.5 psi). 



• Fluid temperature: +3°C to +50°C (+37.4°F to 122°F) - dependent on the NaCl concentration 

• Ambient temperature: +3°C to +50°C (+37.4°F to 122°F) 


temperature. 

All critical parts of the APP pump are made of SAF 2507. 

If the APP pump is operated at high salinity, always flush the pump with fresh water at operation stop in order to minimise the risk 

of crevice corrosion. 

904L / SAF 2205 


7.2 Storage: 

• Storage temperature: -40°C to +70°C (+37.4°F to 122°F) – provided that the APP pump is drained of fluid and stored 

”plugged”. 



8. Noise level 

The chart indicates the noise level in dB(A) measured at a distance of 1 m from the APP pump in a reverberation room. 

Type 

60 bar (580 psi) 

1500 rpm 

60 bar (580 psi) 

1800 rpm 

80 bar (2000 psi) 

1500 rpm 

80 bar (2000 psi) 

1800 rpm 

APP5.1 74 79 73 78 

APP6.5 74 79 73 78 

APP7.2 74 79 73 78 

APP8.2 74 79 73 78 

APP10.2 74 79 73 78 

Generally, noise will be reduced if speed is reduced and vice versa. Use flexible hoses in order to minimize vibrations and noise. 

Since the APP pump is typically mounted on a bell housing or frame, the noise level can only be determined for the complete unit 

(system). 

It is therefore very important that the APP pump is mounted correctly on a frame with dampers to minimize vibrations and noise. 

The noise level is influenced by: 

• The speed of the pump, high rpm create more noise than low rpm 

• Rigid mounting of the pump generates more noise than flexible mounting 

• Pipe mounting direct to the pump increases the noise level compared to a flexible hose 

9. Filtration 



the pump. 



have only 90% filtration efficiency. This means that for each 100,000 particles reaching the filter, 10,000 particles pass through it 

compared to only 20 particles in a filter with an efficiency of 99.98%. 



521B0851 DKCFN.PD.010.FB1.02 3

10. Dimensions 

10.1 APP pump 

Description 

APP5.1 and APP10.2 

C Bleeding M6, Hexagon AF = 5 mm 

D 


12 × 8 × 70 

(0.44 × 0.31 × 2.76) 

I Inlet connection M42 x 1½ mm; 13 mm (0.51 in) deep 

O Outlet connection M42 x 1½ mm; 13 mm (0.51 in) deep 

Pump mounting flange 

125 A2 

10.2 Complete unit 

Pump A (mm) B (mm) C (mm) D (mm) E (mm) F (mm) IEC Electric motor 

APP5.1 350 415 160 254 210 505 11 kW, FPC 160 M-4 

APP6.5 350 415 160 254 254 560 15 kW, FPC 160 L-4 

APP7.2 350 415 160 254 254 560 15 kW, FPC 160 L-4 

APP8.2 350 460 180 279 241 590 18.5 kW, FPC 180 M-4 

APP10.2 350 460 180 279 279 630 22 kW, FPC 180 L-4 

APP10.2 400 505 200 318 305 660 30 kW, FPC 200 L-4 

For inlet and outlet connections data, see “Accessories catalogue” (521B0903). 

DKCFN.PD.010.FB1.02 521B0851


11.1 Mounting 

The figure below illustrates how to mount the APP pump and connect it to an electric motor/combustion engine. 




If alternative mounting is required, please contact Danfoss Sales Organization for further information. 


Note: Any axial and/or radial loads on the shaft must be avoided, see “User guide” (521B0888). 

Min. 3 mm 

A 

B 

C 

The APP pump should be connected to the rest of the plant with a flexible hoses. 

11.2 Open-ended systems with water supply from tank 

In order to eliminate the risk of cavitation, a positive inlet pressure should always be maintained by observing the following 

guidelines: 

1. Place the tank (1) above the APP pump inlet (water level in tank should always be above the pump). 

2. Place a filter (2) in the water supply line in front of the tank. 

3. Dimension the inlet line (3) with minimum pressure drop (large internal diameter, minimum length of pipe, avoid bends and 

fittings with small internal diameter). 

11.3 Open-ended system with direct water supply 

In order to eliminate the risk of cavitation, a positive inlet pressure is always to be maintained at min. 0.5 bar (7.3 psi) and max. 5 bar 

(72.5 psi). 

1. Place the filter (1) in the water supply line in front of the APP pump. 

2. Place a monitoring pressure switch (2) set at min. 1 bar (14.5 psi) between filter and pump inlet. The monitoring switch must 

stop the pump at pressures lower than 1 bar (14.5 psi) At speeds above 1500 rpm - use 2 bar (29 psi) as set point. 

521B0851 DKCFN.PD.010.FB1.02 5

11.4 RO system with APP pump 

1. For easy system bleeding and flushing, apply a bypass non-return valve (1) in parallel with the APP pump. 

2. Place an inlet filter (2) in front of the APP pump (3). Please consult section 9, “Filtration” for guidance on how to select the 

right filter. Throughly clean pipes and flush system prior to start-up. 

3. Place a monitoring pressure switch (6) set at min. 1 bar between filter and pump inlet. The monitoring switch must stop the 

pump at pressures lower than 1 bar (14.5 psi). Above 1500 rpm - use 2 bar (29 psi) as set point. 

4. Dimension the inlet line to obtain minimum pressure loss (large flow, minimum pipe length, minimum number of bends/ 

connections, and fittings with small pressure losses). 

5. In order to eliminate the risk of damage and cavitation, a positive pressure at the inlet (4) is always to be maintained at min. 

0.5 bar (7.3 psi) and max. 5 bar (72.5 psi). At speeds above 1500 rpm the pressure at the inlet of the APP pump must be min. 

2 bar (29 psi). 

6. Use flexible hoses (5) to minimize vibrations and noise. 

7. Install a safety valve (7) in order to avoid system damage as the APP pump creates pressure and flow immediately after startup, 

regardless of any counter-pressure. 

Feed 

2 

5 4 

1 

3 

APP 

5 

7 

Permeate 

6 

M 

Brine 

12. Service 

Provided that the APP pump has been running according to the Danfoss specifications on pre-filtration, pressure, and rotation 

speed, Danfoss guarantees minimum 8000 hours operation, however max. 18 months from date of sale. 






flush the APP pump when the system is shut down. 

The shaft sealing in the APP pump is made of Hasteloy C. At high TDS and high water temperature, the service life of the shaft 

sealing will be reduced. For these applications it is recommended to replace the shaft sealing after approx. 4000 hours operation. 


Water acts as lubricant in the APP pump. Thus there is no oil in the pump. 



12.2 Repair 

In case of irregular function of the APP pump, please contact the Danfoss RO Solutions Sales Organisation. 

DKCFN.PD.010.FB1.02 521B0851

DATA SHEET 

Water Pumps 

APP24 - 26 


APP24 - APP26 pumps are designed to supply low viscosity and corrosive fluids under high pressure, eg. in seawater reverse osmosis 

filtration applications and for high pressure salt water pumping. 

The pumps are based on the axial piston principle enabling a very light and compact design, and they are designed so that the 


All parts included in the pumps are designed to provide long service life, i.e. long service life with a constantly high efficiency and 

minimum service required. 


pump displacement. 

2. Benefits 





• Long service life (Danfoss guarantees 8000 hours maintenance-free operation) 

• All parts of the pump are made of non corrosive materials eg. Duplex (SAF 2205/EN1.4462) and 

Super-duplex (SAF 2507/EN1.4410) stainless steel and carbon reinforced PEEK 

• High efficiency 







6: Valve/thrust plate 



9: Spring 




PRELIMINARY 

Frequency 50 Hz 60 Hz 

APP pumps APP24-50 APP26-50 APP24-60 APP26-60 

Rated speed rpm 1200 1200 1200 1200 

Maximum speed rpm 1200 1200 1200 1200 

Minimum speed rpm 700 700 700 700 

Geometric displacement 

cm 3 /rpm 352 380 352 380 

in 3 /rpm 21.5 23.2 21.5 23.2 

Flow (1200 rpm) m 3 /h 24 26 24 26 

gpm 105.7 114.5 105.6 114.5 

Max. pressure 

bar 80 80 80 80 

psi 1160 1160 1160 1160 

Min. pressure 

bar 40 40 40 40 

psi 580 580 580 580 


kW 64 69 64 69 

max. speed and 80 bar (1160 psi): 

hp 86 92 86 92 

Weight 

kg 125 125 125 125 

lb 275.6 275.6 275.6 275.6 

521B0852 DKCFN.PD.010.FC1.02 09-2006


When using the diagram shown below, it is easy to select the pump which fits the application best if the flow required and the 

rotation speed (rpm) of the pump are known. 

30 

25 

20 

m3/h 

15 

10 

APP26-50Hz 

APP24-50Hz 

APP26-60Hz 

APP24-60Hz 

5 

0 

900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 

rp m 





5. Dimensions 


Rated flow 

PRELIMINARY 

Description 

E 


APP24 - APP26 

12 × 8 × 70 

(0.47 × 0.31 × 2.76) 

F Bleeding G ¼”, Hexagon AF = 8 mm 

I Inlet connection 3” hose pipe 

O Outlet connection 2½ Victaulic 

Pump mounting flange 180 B 4 


Water supply to the pump is either made from a tank placed above the pump or directly from the mains. The pressure at the pump 

inlet (I) must be in the range: 2 - 5 bar (29 - 72.5 psi) 

DKCFN.PI.010.FC1.02 521B0852



• Fluid temperature: +3°C to +50°C (dependent on the NaCl concentration) 

• Ambient temperature: +3°C to +50°C 


temperature. 

All critical parts of the APP water pump is made of SAF 2507. 

If the water pump is operated at high salinity, always flush the the water pump with fresh water at operation stop in order to 

minimise the risk of crevice corrosion. 


7.2 Storage: 

• Storage temperature: -40°C to +70°C – provided that the pump is drained of fluid and stored ”plugged”. 



8. Filtration 



the pump. 



have only 33% filtration efficiency. 




9.1 Mounting 

PRELIMINARY 

The figure below illustrates how to mount the pump and connect it to the electric motor/combustion engine. 




If alternative mounting is required, please contact Danfoss RO Sales Organization for further information. 


Note: Any axial and radial loads on the shaft must be avoided. 

A 

B 

C 

521B0852 DKCFN.PI.010.FC1.02 3

10. Dimensions, complete unit 

11. Service 

Pump A (mm) B (mm) C (mm) D (mm) E (mm) F (mm) IEC Electric motor 

APP24 550 620 250 406 349 770 55 kW, FPC 250 M-4 

APP26 550 920 280 457 368 845 75 kW, FPC 280 S-4 

Provided that the pump has been running according to the Danfoss specifications on pre-filtration, pressure, and rotation speed, 

Danfoss guarantees minimum 8000 hours operation, however max. 18 months from date of sale. 





E 


flush the pump when the system is shut down. 

PRELIMINARY 

The shaft sealing in the APP pump is made of Hasteloy C. At high TDS and high water temperature, the service life of the shaft 

sealing will be reduced. For these applications it is recommended to replace the shaft sealing after approx. 4000 hours operation. 


Water acts as lubricant in the APP. Thus there is no oil in the the pump. 



11.2 Repair 

In case of irregular function of the APP, please contact the Danfoss RO Solutions Sales Organisation. 

D 

DKCFN.PI.010.FC1.02 521B0852

The Danfoss APP pumps 

The Danfoss Axial Piston Pump (APP) is a positive 

displacement pump with an almost constant flow (+/- 1%) 

to speed ratio. 

The design originating from oil hydraulics and 

subsequently redesigned by Danfoss, during the last 15 

years, to pump tap and seawater. Tens of thousands of 

pumps are in operation worldwide proving the pumps to 

be among the most cost-effective and reliable pumps for 

membrane applications, both as main high-pressure 

pumps but also for recovering energy as reversing 

pumps (motors) in the reject line. 

The pumps are made in materials incorporating Duplex 

and Super-duplex materials as standard. 

With Danfoss APP pumps you get the following benefits: 

• Low energy consumption 

Total efficiencies up to 95 percent – among the most efficient in the market. 

• Long service life 

Danfoss guarantees service free operation for more than 8,000 hours thanks to two design features: 

• No oil lubrication: the medium itself lubricates the pump -no risk for contamination of the permeate. 

• No need for service on a regular basis: the mechanical shaft is the only seal in the pump. 

• Easy service 

• Its easy and quick to assemble and dissemble the pump - less 1 / 2 then hour. 

• Corrosion resistance 

All wetted parts of the pump are designed in duplex, super duplex stainless steel and polymer, ensuring 

resistance to corrosive and low viscosity fluids, e.g. seawater and brackish water. 

• High-pressure operation 

Continuous operation at a discharge pressure between 10 and 80 bar (145-1160 psi). Higher discharge 

pressures are available on request. 

• Wide flow range 

One pump size covers the same flow range as several centrifugal pumps, because the flow is a linear 

function of the speed (rpm). The pumps run at speeds between 700 and 3,450 rpm with the same 

efficiency. 

• Low pulsation 

A design featuring up to nine pistons reduces pressure pulsations in the discharge line down to 1.5 

percent, rendering pulsation dampers superfluous addition, and reducing installing cost. 

• Compact design 

The most compact pump on the market. Giving system builders a free hand to design more compact 

systems. The pump may also be directly mounted onto an electrical motor via a bell housing with a 

flexible coupling. No need for frames, belt drive or gearbox.

Since one of our goals is to facilitate supply chain optimization for our customers we offer: 

• High-Pressure Pumps 

• Electrical Motors 

• Frequency Inverters 

• Soft Starters 

• Valves 

• Pressure Transmitters 

• ….and all kinds of "around-the-pump" accessories 

I would especially like to introduce our new line of check 

valves, standpipes and high pressure hoses with victaulic 

connections in duplex. 

Danfoss A/S RO-Solution can supply all APP pumps with ATEX approval mounted with EX-proof Zone II motors 

via stainless steel housing. 

Cost-effective operation and service due to light weight 

and compact design: 

• Flexibility in design of desalination units. 

• Mounted on motor frame – only one frame 

needed e.g. no alignment. 

• No belt-drive or gearbox 

• Replacement without lifting gear 

• Easy and quick replacement. 

Emergency stock for all pumps for overnight shipment for urgent service situations…..setting new standards 

For Further information please visit our website : www.danfoss.com/nessie/rosolution 

Or contact us at Danfoss RO-Solutions: 

Torben Østerby 

Anders Grum Kjærgaard 

Sales Manager, Asia 

Sales Manager 

Direct tel.: +45 7488 5272 Direct tel.: +45 7488 7320 

Cell Phone.: +45 2343 5272 Cell Phone.: +45 5133 7320 

E-mail: toe@danfoss.com 

E-mail: kjaergaard@danfoss.com 

Fax.: +45 7445 3831 Fax.: +45 7445 3831

data sheet

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