SUN HYDRAULICS
QPADLDN
$169.96 USD
- SUN HYDRAULICS
- Material:QPADLDN
- Model:QPAD-LDN
- 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 QPADLDN (Material Number: QPADLDN) is an accumulator sense, pump unload pilot valve specifically engineered to monitor pressure in an accumulator at port 1. Upon reaching the designated pressure setting, the valve connects port 2 to port 3, allowing a relief valve to vent and unloading the pump. It features a precise 50% ratio between unload setting and reset; if pressure at port 1 drops below this threshold, port 2 is blocked from port 3, reactivating the pump to recharge the accumulator. A separate check valve is necessary between port 1 and the pump for optimal operation. The spool design ensures a consistent differential ratio due to its fixed diameters that resist wear over time. The valve minimizes potential silting with tight clearances between the spool and sleeve and includes a seal on the pilot piston diameter. Additionally, a separate drain line is crucial for preventing erratic behavior caused by tank line pressure changes. System design must account for operating pressures and flow rates as these factors influence unloading valve performance; low pressures and differentials require precise system calibration while high flow rates can increase pressure drops affecting differential margins. The QPADLDN incorporates Sun's floating style construction to reduce internal binding risks from installation torque or machining variations. It operates with a maximum pressure of 5000 psi (350 bar) and has a pilot flow capacity of 46 in\u00b3/min (0.75 L/min). The adjustment mechanism requires up to five clockwise turns to increase settings, with specific torque specifications for installation and locknut adjustments provided for secure setup.
The Sun Hydraulics QPADLDN (Material Number: QPADLDN) is an accumulator sense, pump unload pilot valve specifically engineered to monitor pressure in an accumulator at port 1. Upon reaching the designated pressure setting, the valve connects port 2 to port 3, allowing a relief valve to vent and unloading the pump. It features a precise 50% ratio between unload setting and reset; if pressure at port 1 drops below this threshold, port 2 is blocked from port 3, reactivating the pump to recharge the accumulator. A separate check valve is necessary between port 1 and the pump for optimal operation. The spool design ensures a consistent differential ratio due to its fixed diameters that resist wear over time. The valve minimizes potential silting with tight clearances between the spool and sleeve and includes a seal on the pilot piston diameter. Additionally, a separate drain line is crucial for preventing erratic behavior caused by tank line pressure changes. System design must account for operating pressures and flow rates as these factors influence unloading valve performance; low pressures and differentials require precise system calibration while high flow rates can increase pressure drops affecting differential margins. The QPADLDN incorporates Sun's floating style construction to reduce internal binding risks from installation torque or machining variations. It operates with a maximum pressure of 5000 psi (350 bar) and has a pilot flow capacity of 46 in\u00b3/min (0.75 L/min). The adjustment mechanism requires up to five clockwise turns to increase settings, with specific torque specifications for installation and locknut adjustments provided for secure setup.
The accumulator sense, pump unload pilot valve is used to sense pressure in an accumulator at port 1 of the valve and when the pressure at port 1 reaches the valve setting, port 2 connects to port 3 to vent a relief valve and unload the pump. This valve has a 50% ratio between unload setting and reset; when pressure at port 1 falls below 50% of the valve setting, port 2 is blocked from port 3 and the pump will come back online to recharge the accumulator. This valve requires a separate check valve between port 1 and the pump. Another version of the accumulator sense, pump unload valve, QCDD, includes a free-flow check valve for pump flows under 12 gpm (50 L/min).
- 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-11A |
| Series | 1 |
| Capacity | 46 in³/min.0,75 L/min. |
| Maximum Operating Pressure | 5000 psi350 bar |
| 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: 990-011-006 |
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