SUN HYDRAULICS
QCDBCDN
$180.90 USD
Tags:
- SUN HYDRAULICS
- Material:QCDBCDN
- Model:QCDB-CDN
- 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 QCDBCDN (QCDBCDN) is an accumulator sense, pump unload pilot valve specifically designed to sense 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 particular model features a 20:1 ratio between unload setting and reset, ensuring that when the pressure at port 2 falls below 80% of the valve setting, port 3 is blocked from port 4, allowing the pump to recharge the accumulator. It includes an integral free-flow check valve suitable for pump flows up to 15 gpm (60 L/min). For higher capacity pumps, a different model, QPAB, which requires a separate check cartridge, is recommended. The QCDBCDN maintains a fixed differential ratio due to its spool design with diameters that do not wear or change over time. Minimum clearances between the spool and sleeve and a sealed pilot piston diameter reduce silting potential. A separate drain line is necessary to prevent erratic operation from tank line pressure fluctuations. When selecting adjustment ranges, careful consideration should be given due to system pressure drops and flow impacts on unloading valves' operation. The product specifications include a cavity type T-21A Series 1 with a maximum operating pressure of 5000 psi (350 bar), check cracking pressure of 4 psi (0.3 bar), and a pilot flow capacity of 46 in\u00b3/min (0.75 L/min). The adjustment can be increased by turning clockwise up to five turns with specific torque requirements for installation and locknut adjustments. The model weighs approximately .35 lb (0.15 kg) and utilizes Viton seal kits for durability.
The Sun Hydraulics QCDBCDN (QCDBCDN) is an accumulator sense, pump unload pilot valve specifically designed to sense 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 particular model features a 20:1 ratio between unload setting and reset, ensuring that when the pressure at port 2 falls below 80% of the valve setting, port 3 is blocked from port 4, allowing the pump to recharge the accumulator. It includes an integral free-flow check valve suitable for pump flows up to 15 gpm (60 L/min). For higher capacity pumps, a different model, QPAB, which requires a separate check cartridge, is recommended. The QCDBCDN maintains a fixed differential ratio due to its spool design with diameters that do not wear or change over time. Minimum clearances between the spool and sleeve and a sealed pilot piston diameter reduce silting potential. A separate drain line is necessary to prevent erratic operation from tank line pressure fluctuations. When selecting adjustment ranges, careful consideration should be given due to system pressure drops and flow impacts on unloading valves' operation. The product specifications include a cavity type T-21A Series 1 with a maximum operating pressure of 5000 psi (350 bar), check cracking pressure of 4 psi (0.3 bar), and a pilot flow capacity of 46 in\u00b3/min (0.75 L/min). The adjustment can be increased by turning clockwise up to five turns with specific torque requirements for installation and locknut adjustments. The model weighs approximately .35 lb (0.15 kg) and utilizes Viton seal kits for durability.
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 20% ratio between unload setting and reset; when pressure at port 2 falls below 80% 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, QPAB, 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 |
Show FAQ
Additional Resources
- QuickDesign with SmartConnect Offers Drag-and-Drop Schematic Tool
- Accumulator Sense, Pump Unload Valves
- Sun Offers Zinc-Nickel Plating for Corrosion Resistance
- Sun Cartridges with EPDM Seals
- Sun Expands Corrosion-Resistant Solutions
- CavitySaver multi-function valves deliver single-cartridge solutions
- Series 4 PLUS Cartridges Offer Higher Flows with Lower Pressure Losses
- Manufacturing Sun Cartridge Cavities
- Circuit Savers
- Sun Model Code Explanation; 999-901-334
- Units of Measure, Settings, and Conversions
- Cartridges: Materials of Construction
- Cavity Information (S-171) and Tooling
- Fluid and Temperature Recommendations
- Sun's Floating Style Screw-In Cartridge
- Performance Data