Differences Between Danfoss APP, PAH, and PAHT Pumps

Danfoss manufactures a wide range of high-pressure axial piston pumps tailored for different industries. While they share efficiency and reliability, each pump series—APP, PAH, and PAHT—is optimized for specific water types and applications. Understanding these differences helps engineers, operators, and buyers select the right pump for their system.

APP Pumps – Reverse Osmosis Specialists

APP pumps are compact, energy-efficient axial piston pumps designed for seawater reverse osmosis (SWRO). They are widely used in desalination plants, offshore platforms, and marine vessels.

Applications: Reverse osmosis for seawater and brackish water

Key Features:

• High efficiency with low energy consumption
• Simple construction with fewer parts for easy maintenance
• Flow range from 0.6 m³/h to 86 m³/h
• Suitable for land-based, marine, and offshore installations

PAH Pumps – Tap Water & Industrial Use

PAH pumps are positive displacement axial piston pumps designed for tap water and industrial high-pressure applications. Unlike centrifugal pumps, they deliver a constant flow regardless of discharge pressure.

Applications: Tap water pressurization, industrial cleaning, humidification, and cooling.

Key Features:

• Zero risk of lubricant contamination (water lubricated)
• Long service life with minimal maintenance
• High efficiency and low energy costs
• Flow proportional to RPM, ensuring predictable performance

PAHT Pumps – Ultra-Pure & Technical Water

PAHT pumps are engineered for ultra-pure and technical water applications, where contamination must be avoided. They are commonly used in electronics manufacturing, automotive parts cleaning, and adiabatic cooling systems.

Applications: Ultra-pure water, electronics, humidification, and cooling. 

Key Features:

• Water-lubricated design, eliminating need for oil
• Compact and lightweight construction
• Very high mechanical efficiency wiith negligible pulsation
• Stainless steel AISI 316 design for hygiene and durability

FAQs

1: Which pump is best for seawater desalination?
The APP pump is specifically designed for seawater reverse osmosis, offering high efficiency and reliability.

2: Can PAH pumps be used for seawater?
No, PAH pumps are optimized for tap water and industrial applications, not seawater.

 3: Why choose PAHT pumps over APP or PAH?
PAHT pumps are ideal when ultra-pure water is required, such as in electronics or medical industries, because they eliminate contamination risks.