SUN HYDRAULICS
PVDALDN

$115.80 USD

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SUN HYDRAULICS
Material:PVDALDN
Model:PVDA-LDN
Summary:Cartridge

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***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 PVDALDN (PVDALDN) is an externally drained, pilot-operated pressure reducing/relieving valve designed to maintain a constant reduced pressure at port 1 while providing full-flow relief from port 1 to tank port 3. It is insensitive to the pressure at tank port 3 due to its pilot section being drained at port 4, allowing for remote control by pilot or 2-way valves. The maximum pressure at port 3 should not exceed 3000 psi (210 bar), and the recommended maximum inlet pressure varies based on the adjustment range, with ranges A, B, and H tested up to a differential of 3000 psi (210 bar). This valve features very low deadband transition between reducing and relieving modes and exhibits exceptionally flat pressure-flow characteristics with high stability and low hysteresis. The drain port pressure directly adds to the valve setting in a 1:1 ratio, which should not exceed 5000 psi (350 bar). Although it is not fast-acting, this valve is suitable for applications where dynamic response is not critical. It incorporates Sun's floating style construction to minimize binding due to installation torque or machining variations. For reverse flow from reduced pressure port 1 to inlet port 2, a separate check valve may be needed as the main spool may close under such conditions. The valve's cavity is T-21A Series-1 with a capacity of up to 10 gpm (40 L/min) and has factory-established pressure settings with specific torque requirements for installation. The PVDALDN model weighs approximately .30 lb (.15 kg) and uses Viton seal kits for optimal performance in hydraulic systems requiring precise pressure control.

Description

Externally drained, pilot-operated pressure reducing/relieving valves reduce a high primary pressure at the inlet (port 2) to a constant reduced pressure at port 1, with a full-flow relief function from port 1 to tank (port 3). Draining the pilot section at port 4 makes these valves insensitive to pressure at tank (port 3) and provides a means for remote control by pilot or 2-way valves.

Maximum pressure at port 3 should be limited to 3000 psi (210 bar).
Pilot operated valves exhibit very low dead-band transition between reducing and relieving modes.
Recommended maximum inlet pressure is determined by the adjustment range. Ranges D, E, N, and Q are tested with a 2000 psi (140 bar) maximum differential between inlet and reduced pressure. Ranges A, B, and H are tested with a 3000 psi (210 bar) maximum differential between inlet and reduced pressure. Ranges C and W are tested with 5000 psi (350 bar) of inlet pressure.
Pressure at port 4 should not exceed 5000 psi (350 bar).
Pilot operated valves exhibit exceptionally flat pressure/flow characteristics, are very stable and have low hysteresis.
Pressure on the drain (port 4) is directly additive to the valve setting at a 1:1 ratio and should not exceed 5000 psi (350 bar).
Pilot operated reducing, reducing/relieving valves by nature are not fast acting valves. For superior dynamic response, consider direct acting valves.
W and Y controls (where applicable) can be specified with or without a special setting. When no special setting is specified, the valve is adjustable throughout its full range using the W or Y control. When a special setting is specified, this setting represents the maximum setting of the valve.
Full reverse flow from reduced pressure (port 1) to inlet (port 2) may cause the main spool to close. If reverse free flow is required in the circuit, consider adding a separate check valve to the circuit.
By controlling the pressure at the drain (port 4), the effective setting of the valve can be increased over the nominal valve setting.
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	10 gpm40 L/min.
Factory Pressure Settings Established at	blocked control port (dead headed)blocked control port (dead headed)
Maximum Operating Pressure	5000 psi350 bar
Control Pilot Flow	7 - 10 in³/min.0,11 - 0,16 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	.30 lb0,15 kg
Seal kit - Cartridge	Viton: 990-021-006

Show FAQ

How big is a drop of hydraulic oil?	There are exactly 250 Sun drops in a cubic inch or 15 in a cc.
Direct acting or pilot operated - what do I use?	Direct-acting valves are used to prevent over pressure, and pilot-operated valves are used to regulate pressure. If you are unsure, use a direct-acting valve. Sun's direct acting valves are very fast, dirt tolerant, stable, and robust. Sun's pilot-operated valves are moderately fast, they have a low pressure rise vs. flow curve, and they are easy to adjust.
Can I back flow through a reducing valve from port 1 to port 2?	Yes. A reducing or reducing/relieving valve is normally open. If the pressure in the secondary circuit is less than the setting, it will be open.2 caveats: (1) If the valve is in the reducing mode and you suddenly reverse the flow, the valve will not have time to open and will shift into relieving mode or (2) If the back flow generates a pressure drop through the valve that exceeds the setting, the valve will shift into the relieving mode.When in doubt, use a reverse flow check.
What are the tolerances on pressure settings for Sun's pressure control valves?	Pressure setting tolerances are listed in our Performance Data page. A link to this page can also be found in the Additional Resources tab of the applicable product page.
I need a reducer on B. Can I connect the drain to A?	Yes. If you look in the sandwich section you will see that we offer many such packages. When you are pressurizing B, A is connected to tank, allowing the reducer to do its job. When you reverse, the drain or tank port of the reducer is pressurized by A. This increases the setting of the reducer and helps keep the reducer open in the reverse flow direction.
What do you mean by maximum differential?	Our reducing valves are outside-in valves; the supply pressure on the outside of the working parts is higher than the inside. At some pressure differential, the outside (sleeve) will close in on the piston and cause the valve to stick. A D range is adjustable from 25 to 800 psi with a maximum differential of 2000 psi. This means you could set the valve at 600 psi and expect it to work correctly with a supply pressure of 2600 psi. The valve may work at higher differentials, but we do not recommend it. The W and C ranges are tested over their entire range with an inlet pressure of 5000 psi. All direct-acting valves are tested with an inlet pressure of 5000 psi.
Will your reducing/relieving valve relieve my pump to tank?	No. A reducing/relieving valve throttles a supply of oil to maintain a set pressure in a secondary circuit. The valve is open until the secondary or downstream pressure rises to the setting of the valve at which time it starts to close to limit the pressure. If the secondary or downstream pressure is caused to go above the setting, the valve shifts into relieving mode and throttles the secondary circuit back to tank to prevent over-pressure. At no time can the valve connect the supply to tank.

Additional Resources

Notes:

Maximum pressure differentials for spring ranges: A and B are 3000 psi (210 bar) D and E are 2000 psi (140 bar) W is 5000 psi (350 bar) inlet pressure

SUN HYDRAULICSPVDALDN

Additional Resources

SUN HYDRAULICS
PVDALDN