Normally closed, balanced poppet, logic element - pilot-to-open
This is a normally closed, balanced poppet, switching element. Pilot pressure at port 3 shifts the valve to the open position.
- Unique balanced construction provides predictable switching with 5000 psi (350 bar) at both ports 1 and 2, with the external drain open and a minimum pilot pressure of 400 psi (30 bar).
- These valves are hydraulically balanced between port 1 and port 2.
- Port 1 and port 2 are fully sealed from port 3 and port 4. Ports 3 and 4 are positively sealed.
- Any backpressure at the drain port is directly additive to the required pilot pressure for reliable operation.
- Leakage rate between port 1 and port 2 is very low, typically less than 10 drops/min. at 5000 psi (0,7 cc/min at 350 bar).
- Valve will reseat when the pilot pressure falls below 145 psi (10 bar).
- Cartridges configured with EPDM seals are for use in systems with phosphate ester fluids. Exposure to petroleum based fluids, greases and lubricants will damage the seals.
- All ports will accept 5000 psi (350 bar).
- 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 |
Minimum Pilot Pressure Required to Shift Valve | 400 psi28 bar |
Maximum Valve Leakage at 110 SUS (24 cSt) | 10 drops/min.@5000 psi0,7 cc/min.@350 bar |
Pilot Volume Displacement | .01 in³0,16 cc |
Pilot Passage into Valve | .03 in.0,8 mm |
Valve Hex Size | 7/8 in.22,2 mm |
Valve Installation Torque | 30 - 35 lbf ft41 - 47 Nm |
Model Weight | .35 lb0,15 kg |
Seal kit - Cartridge | Buna: 990021007 |
Seal kit - Cartridge | EPDM: 990021014 |
Seal kit - Cartridge | Polyurethane: 990021002 |
Seal kit - Cartridge | Viton: 990021006 |
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.
Because of the very high ratio, the COFO has limited capacity. The discharge path is across a .050 inch (1,3 mm) diameter orifice. If you have large accumulators combined with low precharge pressures, this may not discharge the energy quickly enough. Using the COFO XDN cartridge in conjunction with an LODA XDN will provide capacity for larger applications.
There are exactly 250 Sun drops in a cubic inch or 15 in a cc.
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