SUN HYDRAULICS
QCDDKDV
$197.47 USD
- SUN HYDRAULICS
- Material:QCDDKDV
- Model:QCDD-KDV
- 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 QCDDKDV (QCDDKDV) is an advanced accumulator sense, pump unload pilot valve specifically designed to monitor pressure in an accumulator through port 2. When the pressure reaches the set threshold, port 3 connects to port 4, effectively venting a relief valve and unloading the pump. This valve maintains a 50% ratio between unload setting and reset; if the pressure at port 2 drops below this threshold, port 3 is blocked from port 4, allowing the pump to recharge the accumulator. It features an integral free-flow check valve suitable for pump flows up to 12 gpm (50 L/min). For pumps with higher capacity, a different model requiring a separate check cartridge is available. The valve ensures precise operation with a pressure differential between unload and reset within \u00b11% of its stated ratio, plus up to an additional 25 psi due to dynamic seal friction. The spool design ensures consistent performance by maintaining fixed differential ratios using diameters on the spool that resist wear over time. Minimal clearances between spool and sleeve and a seal on the pilot piston diameter help reduce silting potential. A separate drain line is necessary to prevent erratic operation due to tank line pressure fluctuations. Careful selection of adjustment range is crucial as system pressure drops and flow rates can impact unloading valves' effectiveness, especially at low operating pressures or high flow rates. The QCDDKDV incorporates Sun\u2019s floating style construction to minimize internal binding risks due to installation torque or machining variations. With a cavity type T-21A, series 1 capacity of 15 gpm (60 L/min), maximum operating pressure of 5000 psi (350 bar), and check cracking pressure of 4 psi (0.3 bar), this model offers robust performance in demanding applications. Its compact design includes specific installation torque requirements and adjustment settings for optimal functionality.
The Sun Hydraulics QCDDKDV (QCDDKDV) is an advanced accumulator sense, pump unload pilot valve specifically designed to monitor pressure in an accumulator through port 2. When the pressure reaches the set threshold, port 3 connects to port 4, effectively venting a relief valve and unloading the pump. This valve maintains a 50% ratio between unload setting and reset; if the pressure at port 2 drops below this threshold, port 3 is blocked from port 4, allowing the pump to recharge the accumulator. It features an integral free-flow check valve suitable for pump flows up to 12 gpm (50 L/min). For pumps with higher capacity, a different model requiring a separate check cartridge is available. The valve ensures precise operation with a pressure differential between unload and reset within \u00b11% of its stated ratio, plus up to an additional 25 psi due to dynamic seal friction. The spool design ensures consistent performance by maintaining fixed differential ratios using diameters on the spool that resist wear over time. Minimal clearances between spool and sleeve and a seal on the pilot piston diameter help reduce silting potential. A separate drain line is necessary to prevent erratic operation due to tank line pressure fluctuations. Careful selection of adjustment range is crucial as system pressure drops and flow rates can impact unloading valves' effectiveness, especially at low operating pressures or high flow rates. The QCDDKDV incorporates Sun\u2019s floating style construction to minimize internal binding risks due to installation torque or machining variations. With a cavity type T-21A, series 1 capacity of 15 gpm (60 L/min), maximum operating pressure of 5000 psi (350 bar), and check cracking pressure of 4 psi (0.3 bar), this model offers robust performance in demanding applications. Its compact design includes specific installation torque requirements and adjustment settings for optimal functionality.
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 50% ratio between unload setting and reset; when pressure at port 2 falls below 50% 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 12 gpm (50 L/min). For higher capacity pumps, another version of accumulator sense, pump unload cartridge, QPAD, 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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