SUN HYDRAULICS
QCDALBN
$187.64 USD
- SUN HYDRAULICS
- Material:QCDALBN
- Model:QCDA-LBN
- Summary:Cartridge
Quantity in stock: 0
***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 QCDALBN (Material Number: QCDALBN) is an accumulator sense, pump unload pilot valve designed to efficiently manage hydraulic systems by sensing pressure in an accumulator at port 2. When the pressure reaches the valve setting, it connects port 3 to port 4 to vent a relief valve and unload the pump. This model features a 15% ratio between unload setting and reset, reactivating the pump when pressure falls below 85% of the set value. It includes an integral free-flow check valve suitable for pump flows up to 15 gpm (60 L/min). For applications requiring higher capacity pumps, a different model, QPAA, is recommended. The QCDALBN maintains a consistent differential ratio due to its spool design, with minimal wear over time. It offers precise operation with clearances and seals that reduce silting risks. A separate drain line is necessary for stable performance and to prevent issues from tank line pressure changes. Careful adjustment range selection is crucial as system characteristics can impact unloading valves' operation; low pressures and differentials require precise design while high flow rates lead to pressure drops affecting valve performance. This model fits cavity T-21A Series 1 with a maximum operating pressure of 5000 psi (350 bar) and includes features like zinc-nickel plating for corrosion resistance. The valve's dimensions include a hex size of 7/8 in (22.2 mm) for installation torque between 30 - 35 lbf ft (41 - 47 Nm), with an internal hex size adjustment screw of 5/32 in (4 mm). It weighs approximately .35 lb (.15 kg) and uses Viton seal kits available under part number 990021006.
The Sun Hydraulics QCDALBN (Material Number: QCDALBN) is an accumulator sense, pump unload pilot valve designed to efficiently manage hydraulic systems by sensing pressure in an accumulator at port 2. When the pressure reaches the valve setting, it connects port 3 to port 4 to vent a relief valve and unload the pump. This model features a 15% ratio between unload setting and reset, reactivating the pump when pressure falls below 85% of the set value. It includes an integral free-flow check valve suitable for pump flows up to 15 gpm (60 L/min). For applications requiring higher capacity pumps, a different model, QPAA, is recommended. The QCDALBN maintains a consistent differential ratio due to its spool design, with minimal wear over time. It offers precise operation with clearances and seals that reduce silting risks. A separate drain line is necessary for stable performance and to prevent issues from tank line pressure changes. Careful adjustment range selection is crucial as system characteristics can impact unloading valves' operation; low pressures and differentials require precise design while high flow rates lead to pressure drops affecting valve performance. This model fits cavity T-21A Series 1 with a maximum operating pressure of 5000 psi (350 bar) and includes features like zinc-nickel plating for corrosion resistance. The valve's dimensions include a hex size of 7/8 in (22.2 mm) for installation torque between 30 - 35 lbf ft (41 - 47 Nm), with an internal hex size adjustment screw of 5/32 in (4 mm). It weighs approximately .35 lb (.15 kg) and uses Viton seal kits available under part number 990021006.
The accumulator sense, pump unload pilot valve is used to sense pressure in an accumulator at port 2 of the valve and when the pressure at port 2 reaches the valve setting, port 3 connects to port 4 to vent a relief valve and unload the pump. This valve has a 15% ratio between unload setting and reset; when pressure at port 2 falls below 85% of the valve setting, port 3 is blocked from port 4 and the pump will come back online to recharge the accumulator. The integral free-flow check valve is suitable for pump flows up to 15 gpm (60 L/min). For higher capacity pumps, another version of accumulator sense, pump unload cartridge, QPAA, which requires a separate check cartridge is available.
- 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.
| Cavity | T-21A |
| Series | 1 |
| Capacity | 15 gpm60 L/min. |
| Maximum Operating Pressure | 5000 psi350 bar |
| Check Cracking Pressure | 4 psi0,3 bar |
| Pressure Drop, Port 1 to Port 2 | 100 psi@15 gpm7 bar@60 L/min. |
| Pilot Flow Capacity | 46 in³/min.0,75 L/min. |
| Adjustment - Number of Clockwise Turns to Increase Setting | 55 |
| Valve Hex Size | 7/8 in.22,2 mm |
| Valve Installation Torque | 30 - 35 lbf ft41 - 47 Nm |
| Adjustment Screw Internal Hex Size | 5/32 in.4 mm |
| Locknut Hex Size | 9/16 in.15 mm |
| Locknut Torque | 80 - 90 lbf in.9 - 10 Nm |
| Model Weight | .35 lb0,15 kg |
| Seal kit - Cartridge | Viton: 990-021-006 |
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Additional Resources
- QuickDesign with SmartConnect Offers Drag-and-Drop Schematic Tool
- Accumulator Sense, Pump Unload Valves
- Sun Offers Zinc-Nickel Plating for Corrosion Resistance
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- Sun Model Code Explanation; 999-901-334
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- Cartridges: Materials of Construction
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- Fluid and Temperature Recommendations
- Sun's Floating Style Screw-In Cartridge
- Performance Data