SUN HYDRAULICS
QCDALCV
$199.55 USD
- SUN HYDRAULICS
- Material:QCDALCV
- Model:QCDA-LCV
- 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 QCDALCV (QCDALCV) 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's set point, it connects port 3 to port 4, venting a relief valve and unloading the pump. This model features a 15:1 ratio between unload setting and reset; once pressure at port 2 drops below 85% of the set value, port 3 is blocked from port 4, allowing the pump to recharge the accumulator. It includes an integral free-flow check valve adequate for pump flows up to 15 gpm (60 L/min). For larger pumps, a different model, QPAA, is recommended as it requires a separate check cartridge. The QCDALCV ensures that the pressure differential between unload and reset remains within \u00b11% of the specified ratio with an additional potential variance of up to 25 psi (1.7 bar) due to dynamic seal friction. Its spool design maintains a fixed differential ratio by using diameters on the spool that resist wear over time. The minimum clearances between its spool and sleeve and its pilot piston seal significantly reduce silting risks. A separate drain line is necessary for installation to avoid erratic operations caused by tank line pressure fluctuations. Key specifications include 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 valve requires careful consideration when selecting adjustment ranges due to system pressure drops affecting unloading valves' operation. It incorporates Sun's floating style construction to minimize internal binding risks due to excessive torque or machining variations during installation.
The Sun Hydraulics QCDALCV (QCDALCV) 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's set point, it connects port 3 to port 4, venting a relief valve and unloading the pump. This model features a 15:1 ratio between unload setting and reset; once pressure at port 2 drops below 85% of the set value, port 3 is blocked from port 4, allowing the pump to recharge the accumulator. It includes an integral free-flow check valve adequate for pump flows up to 15 gpm (60 L/min). For larger pumps, a different model, QPAA, is recommended as it requires a separate check cartridge. The QCDALCV ensures that the pressure differential between unload and reset remains within \u00b11% of the specified ratio with an additional potential variance of up to 25 psi (1.7 bar) due to dynamic seal friction. Its spool design maintains a fixed differential ratio by using diameters on the spool that resist wear over time. The minimum clearances between its spool and sleeve and its pilot piston seal significantly reduce silting risks. A separate drain line is necessary for installation to avoid erratic operations caused by tank line pressure fluctuations. Key specifications include 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 valve requires careful consideration when selecting adjustment ranges due to system pressure drops affecting unloading valves' operation. It incorporates Sun's floating style construction to minimize internal binding risks due to excessive torque or machining variations during installation.
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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