Pilot-to-close check valve
![COBA : Pilot-to-close check valve](https://cmsimages.sunhydraulics.com/cartg_coba.gif)
This valve is a spring biased closed, pilot-to-close check cartridge that has a 3:1 pilot ratio. The valve allows flow from port 1 to port 2 and blocks reverse flow. Pressure at the pilot port opposes pressure at port 1 at a ratio of 3:1. This valve is most often used in regeneration circuits.
- Features hardened steel seats for excellent wear characteristics and contamination tolerance.
- Product is not available with A and B spring ranges (4 and 15 psi (0,3 and 1 bar)).
- Pressure at the port 2 area directly opposes pilot pressure.
- Reverse flow through the valve from port 2 to port 1 is not possible under any condition.
- Nominal pilot ratio is 3:1. This means that a pressure of 1000 psi (70 bar) at the pilot port will close a valve against a pressure of 3000 psi (205 bar) at port 1. Any decay or loss of pilot pressure could allow the valve to open, even if it is a momentary decay or loss.
- 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.
- 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-163A |
Series | 0 |
Capacity | 10 gpm40 L/min. |
Maximum Operating Pressure | 5000 psi350 bar |
Pilot Ratio | 3:13:1 |
Maximum Valve Leakage at 110 SUS (24 cSt) | 1 drops/min.0,07 cc/min. |
Valve Hex Size | 3/4 in.19,1 mm |
Valve Installation Torque | 20 - 25 lbf ft27 - 33 Nm |
Model Weight | .20 lb0,10 kg |
Seal kit - Cartridge | Buna: 990163007 |
Seal kit - Cartridge | EPDM: 990163014 |
Seal kit - Cartridge | Polyurethane: 990163002 |
Seal kit - Cartridge | Viton: 990163006 |
There are exactly 250 Sun drops in a cubic inch or 15 in a cc.
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.
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