Assembly Build Process

Sun's Assembly Build Process allows you to configure a cartridge and manifold, or main stage and pilot stage cartridge, and build a digital assembly in three dimensional space. The resulting output of this process is the assembly product page, including configuration-specific images, symbols, product information and CAD files for download.

The Assembly Build Process can be accessed from either a cartridge or manifold product page. Only valid choices are allowed.

From a manifold page, you must first choose your cartridge function. Once you choose your function, click on the BUILD ASSEMBLY button below the WHERE TO BUY BUTTON. Once clicked, you will be presented with valid cartridges for your manifold. Select the cartridge of your choice and follow the instructions at the top of the page. If your particular combination has been generated before, the resulting assembly page will be available immediately. If not, you will be asked to enter your email address. Once the page is complete, an email will be sent to you including a link to the assembly product page.

From a cartridge product page, click on BUILD ASSEMBLY and you will be presented with a listing of compatible manifolds. In the case of main stage and pilot stage cartridges, you can either build a cartridge to cartridge assembly or a cartridge to manifold assembly. Once your choice has been made, follow the instructions at the top of the page. If your particular combination has been generated before, the resulting assembly page will be available immediately. If not, you will be asked to enter your email address. Once the page is complete, an email will be sent to you including a link to the assembly product page.

Please note that the Assembly Build Process is an automated process. It can be utilized at any time. Pages are generated typically within minutes but delays can occasionally be expected. In the event of a delay, a team at Sun will work to resolve the issue to ensure you receive your information as quickly as possible.

Electro-proportional, direct-acting, pressure reducing/relieving valve with open transition and drain to port 4

Capacity: 5 gpm20 L/min. | Cavity: T-21A

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Technical Features [ + ]

This electro-proportional, direct-acting reducer/reliever valve reduces 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). The valve is biased to the relieving mode. Energizing the coil connects port 2 to port 1. Increasing the current to the coil will proportionally increase the reduced pressure at port 1. If pressure at port 1 exceeds the setting induced by the coil, pressure at port 1 is relieved to port 3. Draining port 4 makes the valve insensitive to pressure at port 3. This valve is open in the transition from reducing to relieving which provides good pressure control and dynamic response. Optional full manual control is available.

Maximum pressure at port 3 should be limited to 3000 psi (210 bar).
All spring ranges are tested for correct operation with 5000 psi (350 bar) inlet pressure.
Direct acting concept provides highly reliable operation in contaminated systems, especially at dead headed conditions.
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).
Leakage specified in Technical Data is out of port 3 with a supply pressure of 2000 psi (140 bar) and the valve set at mid range. This leakage is directly proportional to pressure differential and inversely proportional to viscosity expressed in centistokes.
The transition from reducing to relieving is slightly open. The result is very good pressure control with oil consumption of about 0.1 gpm (0,4 L/min.).
For optimum performance, an amplifier with current sensing and adjustable dither should be used. Dither should be adjustable between 100 - 250 Hz.
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.
Uses for the 'L' manual screw adjustment include: emergency valve setting during power failure or alternatively boosting the valve setting
With the 'L' adjustment screw, all ranges are factory set at zero (adjustment screw fully backed out). With the coil de-energized, clockwise adjustment of the screw will increase the spring bias load up to the maximum setting for that range. With the coil energized, any mechanical pressure setting is directly additive to the coil induced value.
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.

Technical Data [ + ]

Proportional Performance Data [ + ]

Performance Curves [ + ]

FAQs [ + ]

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.

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.

What parts of the Sun cartridge valve are field serviceable?

Only external seals are serviceable. Sun offers replacement seal kits for all cartridge models. The applicable kit part number can be found in the product page's Technical Data table or by using our Cartridge Seal Kit search function located under Accessories. Please note: Converting the external seals from one material to another does not ensure fluid compatibility with that material due to the existence of internal seals within the cartridge.

Related Accessories [ + ]

Notes [ + ]

Additional Resources [ + ]

Coil Information [ + ]

PSDLMDN

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Configuration Rules

Cavity	T-21A
Series	1
Capacity	5 gpm20 L/min.
Maximum Operating Pressure	5000 psi350 bar
Maximum Valve Leakage at 110 SUS (24 cSt)	20 in³/min.330 cc/min.
Adjustment - No. of CW Turns from Min. to Max. setting	55
Solenoid Tube Diameter	.75 in.19 mm
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 (with coil)	1.20 lb0,55 kg
Seal kit - Cartridge	Buna: 990021007
Seal kit - Cartridge	Polyurethane: 990021002
Seal kit - Cartridge	Viton: 990021006
Seal and nut kit - Coil	Viton: 990770006

Hysteresis (with dither)	6%6%
Hysteresis with DC input	<8%<8%
Linearity (with dither)	<2%<2%
Repeatability (with dither)	<2%<2%
Recommended dither frequency	140 Hz140 Hz

PSDL | Cartridges » Pressure Control » Reducing/Relieving | Sun Hydraulics

Assembly Build Process

Assembly Build Process

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Electro-proportional, direct-acting, pressure reducing/relieving valve with open transition and drain to port 4

Symbols for PSDL

Symbols for PSDL

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