You are using an outdated browser. For a faster, safer browsing experience, upgrade for free today.
Sun Hydraulics-QPAALDV-QPAALDV

SUN HYDRAULICS
QPAALDV


$191.01 USD
  • SUN HYDRAULICS
  • Material:QPAALDV
  • Model:QPAA-LDV
  • Summary:Cartridge

Quantity in stock: 0

Note: Sales tax, and shipping will be calculated at checkout.
***Disclaimer: The following summary contains information gathered from various sources such as product descriptions, technical specifications and catalogs. While efforts have been made to provide accurate details, inaccuracies may occur. It is advised to verify all information by contacting Sun Hydraulics directly.***
The Sun Hydraulics QPAALDV (QPAALDV) is an accumulator sense, pump unload pilot valve designed to optimize hydraulic system efficiency by controlling the pressure in an accumulator. When the pressure at port 1 reaches the valve's preset level, this valve connects port 2 to port 3, venting a relief valve and unloading the pump. It features a 15:1 ratio between unload setting and reset, ensuring the pump re-engages when pressure falls below 85% of the set value. For proper operation, a separate check valve is necessary between port 1 and the pump. This model requires careful system design due to potential impacts of low operating pressures and high flow rates on its performance. The QPAALDV maintains its differential ratio through a durable spool design that resists wear over time. Its construction includes minimal clearances between spool and sleeve along with a sealed pilot piston diameter to reduce silting risks. A separate drain line is essential to prevent erratic behavior from tank line pressure fluctuations. The valve operates within a maximum pressure of 5000 psi (350 bar) and has a pilot flow capacity of 46 in\u00b3/min (0.75 L/min). Installation requires specific torque settings for optimal performance. Sun Hydraulics has incorporated their floating style construction in this valve to minimize binding issues due to installation torque or machining variations. The QPAALDV fits into cavity T-11A with Series 1 capacity, weighing approximately 0.35 lbs (0.15 kg). Maintenance is facilitated by using Viton seal kits available under part number 990011006, ensuring long-term reliability in demanding applications.

The accumulator sense, pump unload pilot valve is used to sense pressure in an accumulator at port 1 of the valve and when the pressure at port 1 reaches the valve setting, port 2 connects to port 3 to vent a relief valve and unload the pump. This valve has a 15% ratio between unload setting and reset; when pressure at port 1 falls below 85% of the valve setting, port 2 is blocked from port 3 and the pump will come back online to recharge the accumulator. This valve requires a separate check valve between port 1 and the pump. Another version of the accumulator sense, pump unload valve, QCDA, includes a free-flow check valve for pump flows under 12 gpm (50 L/min).

  • The pressure differential between unload and reset will be within +/- 1% of the stated ratio of the valve with up to an additional 25 psi (1,7 bar) due to dynamic seal friction.
  • The accumulator sensing area is positively sealed.
  • The spool design of this valve allows it to maintain a fixed differential ratio because the areas are created by diameters on the spool that will not wear or change with use.
  • Minimum clearances between the spool and sleeve and a seal on the pilot piston diameter significantly reduce the potential for silting.
  • When applying this cartridge, a separate drain line is required to prevent erratic operation caused by tank line pressure fluctuations.
  • NOTE: Careful consideration should be given when selecting an adjustment range. System pressure drops and flows tend to affect the operation of unloading valves. Low operating pressures combined with low differentials result in a very narrow band between unload and reset, requiring precise system design. High flow rates typically mean high pressure drops, which subtract from the differential the valve has to work with.
  • Sun has designed a variety of standard accumulator/pump unload assemblies with a variety of features. These assemblies can be found on our website under SOLUTIONS: ACCUMLATOR SENSE, PUMP UNLOAD.
  • Incorporates the Sun floating style construction to minimize the possibility of internal parts binding due to excessive installation torque and/or cavity/cartridge machining variations.
CavityT-11A
Series1
Capacity46 in³/min.0,75 L/min.
Maximum Operating Pressure5000 psi350 bar
Pilot Flow Capacity46 in³/min.0,75 L/min.
Adjustment - Number of Clockwise Turns to Increase Setting55
Valve Hex Size7/8 in.22,2 mm
Valve Installation Torque30 - 35 lbf ft41 - 47 Nm
Adjustment Screw Internal Hex Size5/32 in.4 mm
Locknut Hex Size9/16 in.15 mm
Locknut Torque80 - 90 lbf in.9 - 10 Nm
Model Weight.35 lb0,15 kg
Seal kit - CartridgeViton: 990-011-006

Show FAQ

Additional Resources