Complete model designation
Specify the valve size, cracking-pressure option, poppet shape, cover type, orifice location and designation, and design number. The catalogue lists design number 12 for LD sizes 16 through 63.
Yuken Directional and flow control
LD Series logic valves
Select pilot-operated directional or directional and flow control configurations by valve size, poppet cushion and cover type.
6 sizesCatalogue model range
315 Kgf/cm²Maximum operating pressure
130 to 2100L/min. rated flow by size
2:1Poppet-area ratio
Directional and flow control
LD logic valves open and close a two-port circuit in response to pilot-pressure signals. The cartridge element fits into a manifold cavity, with the cover and pilot circuit determining the control function.
Directional configurations and directional and flow control configurations use different cover arrangements. For directional and flow control, Yuken specifies a cushioned poppet together with the appropriate stroke-adjuster cover.
Confirm the complete cartridge, cover and manifold arrangement against the catalogue installation drawings.
Models and rated flow
| Model | Rated flow, L/min. |
|---|---|
| LD-16 | 130 |
| LD-25 | 350 |
| LD-32 | 500 |
| LD-40 | 850 |
| LD-50 | 1400 |
| LD-63 | 2100 |
Rated flow is specified at a pressure drop of 3 Kgf/cm² with fluid viscosity 35cSt. These figures are not an unconditional maximum flow rating.
Maximum operating pressure for the listed models: 315 Kgf/cm².
Cover types and functions
| Code | Catalogue function |
|---|---|
| None | Standard directional-control cover |
| 4 | Directional control with check valve |
| 5 | Directional control with shuttle valve |
| 1 | Directional and flow control with stroke adjuster |
| 2 | Check valve and stroke adjuster |
| 3 | Shuttle valve and stroke adjuster |
Cover codes identify different pilot circuits. Review the corresponding hydraulic symbol before confirming a configuration.
Ordering and configuration
Pilot and switching options
Cracking-pressure code 05 denotes 0.5 Kgf/cm² from A to B and 1 Kgf/cm² from B to A. Code 20 denotes 2 Kgf/cm² from A to B and 4 Kgf/cm² from B to A. The omitted option has no spring. The poppet-area ratio is 2:1.
Selection support
Confirm the valve and pilot circuit
A full model code, nameplate photograph and circuit drawing help identify the required assembly.
- Valve family, size and complete model code
- Operating pressure and required flow
- Cover type, pilot passages and orifice details
- Poppet cushion and cracking-pressure option
- Manifold cavity and mounting drawing
- Hydraulic fluid, seal requirements and quantity
LD logic valve catalogue
Open the LD section of the full Yuken logic valve catalogue for specifications, symbols and installation details.
Enquire about LD logic valves
Send your model code and circuit details to Shree Hydraulics in Belagavi for product selection and quotation enquiries across India.