SUN HYDRAULICS
QCDALBV
$196.57 USD
- SUN HYDRAULICS
- Material:QCDALBV
- Model:QCDA-LBV
- 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 QCDALBV (QCDALBV) 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 15:1 ratio between unload setting and reset, ensuring that when pressure falls below 85% of the valve setting, the pump re-engages to recharge the accumulator. It incorporates an integral free-flow check valve suitable for pump flows up to 15 gpm (60 L/min). For systems requiring higher capacity pumps, a different version, QPAA, is recommended. The QCDALBV maintains a precise pressure differential between unload and reset within \u00b11% of the stated ratio, with an additional allowance for dynamic seal friction. The spool design ensures consistent performance by maintaining fixed differential ratios through durable diameters on the spool that resist wear over time. This design minimizes silting potential due to minimal clearances between spool and sleeve and incorporates a seal on the pilot piston diameter. A separate drain line is essential when applying this cartridge to prevent erratic operations from tank line pressure fluctuations. Selecting an appropriate adjustment range is crucial as low operating pressures combined with low differentials demand precise system design; similarly, high flow rates result in high-pressure drops affecting operational efficiency. This model includes Sun's floating style construction to reduce internal binding risks due to installation torque or machining variations. It fits into cavity T-21A with a maximum operating pressure of 5000 psi (350 bar) and has specific installation requirements such as torque specifications for hex sizes and locknuts. The product weighs .35 lb (.15 kg) and requires Viton seal kit number 990021006 for maintenance.
The Sun Hydraulics QCDALBV (QCDALBV) 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 15:1 ratio between unload setting and reset, ensuring that when pressure falls below 85% of the valve setting, the pump re-engages to recharge the accumulator. It incorporates an integral free-flow check valve suitable for pump flows up to 15 gpm (60 L/min). For systems requiring higher capacity pumps, a different version, QPAA, is recommended. The QCDALBV maintains a precise pressure differential between unload and reset within \u00b11% of the stated ratio, with an additional allowance for dynamic seal friction. The spool design ensures consistent performance by maintaining fixed differential ratios through durable diameters on the spool that resist wear over time. This design minimizes silting potential due to minimal clearances between spool and sleeve and incorporates a seal on the pilot piston diameter. A separate drain line is essential when applying this cartridge to prevent erratic operations from tank line pressure fluctuations. Selecting an appropriate adjustment range is crucial as low operating pressures combined with low differentials demand precise system design; similarly, high flow rates result in high-pressure drops affecting operational efficiency. This model includes Sun's floating style construction to reduce internal binding risks due to installation torque or machining variations. It fits into cavity T-21A with a maximum operating pressure of 5000 psi (350 bar) and has specific installation requirements such as torque specifications for hex sizes and locknuts. The product weighs .35 lb (.15 kg) and requires Viton seal kit number 990021006 for maintenance.
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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