Pilot-to-open, spring-biased closed, unbalanced poppet logic element
Symbols for LKJC
These unbalanced poppet, logic valves are 2-way switching elements that are spring-biased closed. Pressure at either work port 1 or 2 will further bias the valve to the closed position while pressure at port 3 will tend to open it. The force generated at port 3 must be greater than the sum of the forces acting at port 1 and port 2 plus the spring force for the valve to open. NOTE: The pilot area (port 3) is 1.8 times the area at port 1 and 2.25 times the area at port 2.
- These valves have positive seals between port 2 and the pilot area.
- 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.
- Because these valves are unbalanced, operation is pressure dependent. Opening and closing of the poppet are functions of the force balances on three areas: Port 1 = 100%, Port 2 = 80%, and the Pilot Area = 180%.
- These valves are pressure responsive at all ports, therefore it is essential to consider all aspects of system operation through a complete cycle. Pressure changes at any one port may cause a valve to switch from a closed to an open position, or vice versa. All possible pressure changes in the complete circuit must be considered to assure a safe, functional system design.
- All ports will accept 5000 psi (350 bar).
- Corrosion resistant cartridge valves are intended for use in corrosive environments and are identified by the model code suffix /AP for external stainless steel components, or /LH for external zinc-nickel plated components. See the CONFIGURATION section for all options. For further details, please see the Materials of Construction page located under TECH RESOURCES.
- 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-19A |
| Series | 4 |
| Capacity | 120 gpm480 L/min. |
| Maximum Operating Pressure | 5000 psi350 bar |
| Maximum Valve Leakage at 110 SUS (24 cSt) | 10 drops/min.@1000 psi0,7 cc/min.@70 bar |
| Pilot Volume Displacement | .30 in³4,9 cc |
| Pilot Passage into Valve | .09 in.2,3 mm |
| Area Ratio, A3 to A1 | 1.8:11.8:1 |
| Area Ratio, A3 to A2 | 2.25:12.25:1 |
| Valve Hex Size | 1 5/8 in.41,3 mm |
| Valve Installation Torque | 350 - 375 lbf ft474 - 508 Nm |
| Seal kit - Cartridge | Buna: 990019007 |
| Seal kit - Cartridge | EPDM: 990019014 |
| Seal kit - Cartridge | Polyurethane: 990019002 |
| Seal kit - Cartridge | Viton: 990019006 |
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.
- LKJCZPilot-to-open, spring-biased closed, unbalanced poppet logic element with position switch
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