1 Product Overview and Core Technology

　　The Danfoss APP WHC series represents a pinnacle of engineering in the realm of high-pressure pump technology.These axial piston pump models are specifically designed to handle challenging media like wastewater,seawater,and brackish water in demanding industrial applications.As positive displacement pumps,they deliver a fixed volume of fluid with each revolution,maintaining consistent flow rates regardless of discharge pressure variations-a significant advantage over centrifugal pump technologies.

　　Danfoss has engineered the APP WHC series with a focus on reliability and efficiency in harsh operating environments.The pumps belong to the broader APP W HC 15-30 product group and are manufactured in Denmark to exacting quality standards.With maximum flow capacities reaching 248.9 liters per minute(65 gallons per minute)and capable of sustaining continuous outlet pressures up to 120 bar(1740 psig),these pumps provide robust performance for high-pressure reverse osmosis(RO),zero liquid discharge(ZLD),and minimal liquid discharge(MLD)systems.

　　The operational principle of these axial piston pump units centers on multiple pistons arranged in a circular pattern within a cylinder block.As the block rotates against a stationary swash plate,the pistons undergo reciprocating motion,creating the pumping action that moves fluid through the system.This design achieves remarkable volumetric efficiencies exceeding 90%in many applications,significantly reducing energy consumption compared to alternative pumping technologies.

　　2 Technical Specifications and Performance Characteristics

　　The Danfoss APP WHC series demonstrates impressive technical capabilities that make it suitable for intensive industrial applications.The pumps operate within a rotational speed range of 500-1200 RPM,with a geometric displacement of 362 cm³/rev(22.09 in³/rev)for the APP W HC 24/1200 model.This high-pressure pump series requires specific inlet pressure conditions,with continuous operational limits between 2-5 bar(29-72.5 psig)and peak inlet pressure tolerance up to 10 bar(145 psig).

　　Environmental operating parameters are carefully defined for reliable performance.The APP WHC pumps function within medium temperature ranges of 2-50°C(36-122°F)and ambient temperature ranges of 0-50°C(32-122°F).The pumps produce a maximum sound pressure level of 85 dBA during operation,making them suitable for installations where noise control is a consideration.

　　Connection interfaces are standardized with metric M60 threaded ports for both inlet and outlet connections,ensuring compatibility with industrial piping systems.The physical characteristics of these pumps include a compact design with a net weight of 92.5 kg(203.5 lbs)and packaging dimensions of 380x300x300 mm(14.9x11.8x11.8 inches),facilitating easier integration into equipment and systems.

　　3 Design Features and Construction Materials

　　3.1 Robust Material Selection

　　The exceptional durability of the Danfoss APP WHC axial piston pump series stems from its construction using highly corrosion-resistant materials.Critical components are manufactured from duplex steel(EN1.4462/UNS S31803)and super duplex steel(EN1.4410/UNS S32750),providing outstanding resistance to aggressive media like seawater and wastewater.The selection of these advanced materials ensures extended service life even in the most challenging environments where standard stainless steels would succumb to corrosion.

　　Additional specialized materials include carbon fiber-reinforced PEEK(polyether ether ketone)for certain wearing components,combining exceptional strength with corrosion resistance.The shaft seal utilizes NBR(nitrile butadiene rubber)as standard,appropriately matched to the pump's operational parameters and media compatibility.This strategic material selection throughout the pump's construction eliminates the need for lubrication oil,using the pumped media water instead for lubrication,thereby completely avoiding any risk of oil contamination.

　　3.2 Integrated Flush Valve System

　　A significant design feature of the APP WHC series is the integrated flush valve,which allows fluid to circulate from the inlet to the outlet when the pump is not running.This innovative feature prevents stagnation,protects internal components,and ensures immediate readiness for operation.The flush valve system contributes to the pump's exceptional reliability and reduces maintenance requirements between operational cycles.

　　The compact and lightweight design of these pumps,relative to their performance capabilities,facilitates flexible installation options.They can be mounted in either horizontal or vertical orientations,providing valuable flexibility for equipment designers and system integrators working within space-constrained applications.The simplified mechanical design with fewer moving parts enhances reliability while making field maintenance more straightforward.

　　4 Application Areas and Industry Solutions

　　The Danfoss APP WHC axial piston pump series excels in numerous demanding application areas,particularly in water treatment and industrial processes.Their robust construction and high-efficiency performance make them ideally suited for high-pressure reverse osmosis systems for seawater desalination(SWRO),brackish water treatment,and wastewater reclamation.These pumps deliver the consistent high pressure required for RO membrane processes while providing exceptional resistance to corrosive feedwaters.

　　In industrial applications requiring zero liquid discharge(ZLD)and minimal liquid discharge(MLD)systems,the APP WHC pumps provide the reliable high-pressure performance necessary for concentrating waste streams and recovering valuable water resources.Their ability to handle challenging wastewater streams with minimal maintenance requirements makes them particularly valuable in these critical applications where system reliability directly impacts environmental compliance and operational costs.

　　Additional application areas include containerized solutions for hotels,resorts,and residential complexes in coastal areas;mobile systems for humanitarian organizations and military operations;marine systems for ships and yachts;offshore platforms in the oil and gas industry;and municipal water treatment plants.The pumps'compatibility with parallel configuration allows for system scalability to meet varying capacity requirements.

　　5 Operational Advantages and Economic Benefits

　　5.1 Reduced Operating Costs

　　The Danfoss APP WHC high-pressure pump series delivers significant operational cost savings through multiple mechanisms.The exceptional efficiency of the axial piston design,achieving over 90%in many applications,directly translates to lower energy consumption compared to alternative pump technologies.This efficiency advantage becomes increasingly substantial in continuous operation applications,where energy costs represent a significant portion of the total cost of ownership.

　　Maintenance requirements are notably reduced due to the pump's robust construction and extended service intervals.Under appropriate operating conditions,maintenance cycles can extend to 8,000 hours of operation,minimizing both maintenance labor costs and production downtime.The simplified design with fewer components further enhances reliability while making any required maintenance more straightforward to perform,often possible onsite without specialized tools.

　　5.2 Environmental and Safety Benefits

　　The APP WHC series provides significant environmental advantages through its oil-free operation design.By using the pumped water for lubrication instead of oil,these pumps completely eliminate any risk of lubricant contamination in the process fluid.This feature is particularly valuable in applications where product purity is essential,such as potable water production,or where environmental contamination must be avoided.

　　The pumps'exceptional durability and use of corrosion-resistant materials contribute to extended service life,reducing resource consumption for replacement parts and minimizing equipment lifecycle environmental impacts.The high efficiency operation also lowers energy-related carbon emissions,supporting sustainability initiatives.Additionally,the pumps carry CE certification and comply with EU RoHS directives,demonstrating Danfoss'commitment to safety and environmental standards.

　　6 Installation Considerations and System Integration

　　Proper installation is critical for optimizing the performance and service life of Danfoss APP WHC axial piston pump units.The pumps require adequate filtration of the inlet fluid to protect internal components from particulate damage.While specific filtration requirements depend on application conditions,general guidelines recommend appropriate prefiltration to remove solids that could accelerate wear on precision components.

　　The APP WHC pumps offer flexible installation options,supporting both horizontal and vertical mounting orientations without performance compromises.This flexibility enables equipment designers to optimize system layouts for space utilization and service access.The pumps'compact dimensions and relatively lightweight construction facilitate integration into both original equipment and retrofit applications.

　　System designers should note the importance of maintaining minimum continuous inlet pressure requirements of 2 bar(29 psig)to ensure proper operation and prevent cavitation.For applications with variable flow requirements,these pumps can be paired with heavy-duty constant torque frequency converters to adjust output through speed control.The pumps'minimal pressure pulsation eliminates the need for pulse dampeners in most applications,further simplifying system design and reducing installation costs.

　　Frequently Asked Questions(FAQs)

　　What maintenance intervals can be expected with the Danfoss APP WHC axial piston pump?

　　Under normal operating conditions and with proper filtration,the APP WHC series can achieve maintenance intervals up to 8,000 operating hours.The simplified design with fewer wearing components and the use of durable materials like duplex steel and carbon fiber-reinforced PEEK contribute to this extended service interval.Field maintenance is straightforward due to the design simplicity and minimal specialized tools required.

　　How does the axial piston design of the APP WHC series provide advantages over centrifugal pump technology?

　　Unlike centrifugal pumps whose flow rate varies with discharge pressure,axial piston pumps deliver a fixed displacement per revolution,providing consistent flow rates regardless of pressure variations.This positive displacement characteristic makes the APP WHC series particularly suitable for applications requiring stable flows against varying system pressures.Additionally,axial piston technology typically achieves higher operational efficiencies,often exceeding 90%,compared to centrifugal alternatives in high-pressure applications.

　　Can the Danfoss APP WHC pump series handle parallel operation for system expansion?

　　Yes,the APP WHC pumps are designed for parallel configuration,allowing multiple units to operate together to meet increased system capacity requirements.This scalability provides significant flexibility for system designers,enabling capacity expansion without complete system redesign.Parallel operation also offers potential redundancy benefits for critical applications where continuous operation is essential.

　　What materials make the APP WHC series suitable for corrosive applications like seawater desalination?

　　The pumps utilize highly corrosion-resistant materials including duplex steel(EN1.4462/UNS S31803)and super duplex steel(EN1.4410/UNS S32750)for critical wetted components.These specialized stainless steels provide exceptional resistance to chloride-induced stress corrosion cracking and general corrosion in seawater environments.Additional corrosion-resistant materials include carbon fiber-reinforced PEEK for certain wearing components,ensuring extended service life in aggressive media.

　　What are the specific application differences between the standard APP HC and the APP W HC series?

　　While both series share the same fundamental axial piston technology,the APP W HC variants are specifically engineered for wastewater applications.The"W"designation indicates enhanced compatibility with wastewater streams,potentially including modified materials or design features optimized for this challenging duty.For standard seawater,brackish water,and clean water applications,the APP HC series provides optimal performance,while the APP W HC series offers specialized capabilities for wastewater duties.