Accumulator sense, pump unload assembly

Function

Function for XQGF
Port Designators [ + ]
Modifiers Ports
E, E/S Ports P, T, & SYS 1: 1" NPTF; Port SYS 2: 3/4" NPTF; Port G: 1/4" NPTF; Ports D & AUX: 3/8" NPTF;
F, F/S Ports P, T, & SYS 1: 1 1/4" NPTF; Port SYS 2: 1" NPTF; Port G: 1/4" NPTF; Ports D & AUX: 3/8" NPTF;
M, M/S Ports P, T, & SYS 1: SAE 16; Port SYS 2: SAE 12; Port G: SAE 4; Ports D & AUX: SAE 6;
N, N/S Ports P, T, & SYS 1: SAE 20; Port SYS 2: SAE 16; Port G: SAE 4; Ports D & AUX: SAE 6;
X, X/S Ports P, T, & SYS 1: 1" BSPP; Port SYS 2: 3/4" BSPP; Port G: 1/4" BSPP; Ports D & AUX: 3/8" BSPP;
Y, Y/S Ports P, T, & SYS 1: 1 1/4" BSPP; Port SYS 2: 1" BSPP; Port G: 1/4" BSPP; Ports D & AUX: 3/8" BSPP;
Technical Features [ + ]

This valve assembly is meant to charge an accumulator using a fixed displacement pump. When the pressure reaches the set point of the valve, the pump is unloaded. When the pressure drops to the value determined by the fixed percentage of the pilot valve, the pump is brought back on line to recharge the accumulator. The ventable relief serves a dual purpose as a main stage to unload the pump and as a system over-pressure relief.

The assembly has an additional feature; a simple circuit that softens the unloading of the pump.

Technical Data [ + ]
Body Type Line mountLine mount
Mounting Hole Thread .375-16 UNC - 2B in..375-16 UNC - 2B in.
Mounting Hole Depth .88 in.22,4 mm
Mounting Hole Quantity 33
FAQs [ + ]

There are exactly 250 Sun drops in a cubic inch or 15 in a cc.

Reasons to anodize:

  • To increase corrosion resistance. Sun uses 6061-T651 aluminum. It is one of the most corrosion resistant aluminum alloys there is. Whether or not anodizing improves the corrosion resistance of 6061 aluminum is debatable. We have yet to have a manifold returned because of corrosion.
  • Appearance (color). The 2 colors that would appeal to Sun would be blue or black. Unfortunately these are the colors that are hardest to do consistently.
  • To provide a hard wear surface. Sun does not make parts-in-body valves. The manifold is just plumbing. We don't need a wear surface.
  • Because everyone else does it. Bad reason. 

Reasons to not anodize:

  • Cost. It's another process.
  • Logistics. When you make tens of thousands of manifolds a month and you anodize hundreds, it's a problem. Consistency. See above.
  • Stamping. After a body is anodized you cannot do any more stamping without making a mess.
    Inspection. Have you ever tried to look for burrs in a black anodized body? It's the old blackboard factory at night scenario.
  • Torque. You will experience an increase in breakaway torque when removing items from an anodized manifold.
  • Fatigue life. This is the best reason to not anodize. Fatigue failure is a very complex phenomenon. What it takes to initiate a crack is difficult to predict. What it takes to propagate a crack is readily defined. Anodizing produces a very thin, very hard, and very brittle surface on aluminum. The first time you pressurize an anodized aluminum manifold you have initiated fatigue cracks. Whether or not the stress is enough to propagate the cracks is a matter of pressure and manifold geometry. Anodizing an aluminum manifold grossly reduces the fatigue life by anywhere from 20% to 50%.

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.

Notes [ + ]
  • Some applications may require additional volume for a smoother shift. Should this become necessary, an auxillary port has been provided to attach a length of hose for additional volume.
  • Important: Carefully consider the maximum system pressure. The pressure rating of the manifold is dependent on the manifold material, with the port type/size a secondary consideration. Manifolds constructed of aluminum are not rated for pressures higher than 3000 psi (210 bar), regardless of the port type/size specified.
Additional Resources [ + ]