MODEL
LOHA8
Vent-to-open, spring biased closed, unbalanced poppet logic element with pilot
source from port 1 and integral T-8A control cavity
SERIES 3 / CAPACITY: 380 L/min. / CAVITY: T-17A
This valve is an unbalanced, vent-to-open, 2-way logic switching element with an integral pilot control cavity. It is
spring biased closed and uses port 1 as a pilot source. With a pilot 2-way valve in the closed position installed in the
T-8A cavity, the logic element will remain in the closed position. With the pilot valve open, the logic element will
open providing there is a sufficient combination of pressures to overcome the spring force. The force generated at
port 3, plus the spring force, must be greater than the sum of the forces acting at port 1 and port 2 for the valve to
remain closed. NOTE: The pilot area (port 3) is 1.8 times the area at port 1 and 2.25 times the area at port 2.
TECHNICAL DATA
Maximum Operating Pressure 350 bar
Pilot Volume Displacement 4,1 cc
Area Ratio, A3 to A1 1.8:1
Area Ratio, A3 to A2 2.25:1
Pilot Control Cavity T-8A
Control Orifice Diameter 0,8 mm
Seal kit - Cartridge Buna: 990-017-007
Seal kit - Cartridge Polyurethane: 990-017-002
Seal kit - Cartridge Viton: 990-017-006
(D)CRACKING PRESSURE
D 50 psi (3,5 bar)
(N)SEAL MATERIAL
N Buna-N
V Viton
snhy.com/LOHA8
TECHNICAL FEATURES
These valves have positive seals between port 2 and the pilot area.
NOTE: With the -8 control option, the main stage valve should first be installed to the correct torque value. The T-8A pilot control valve should then be installed into
the main stage valve to its required torque value.
The -8 control option allows the pilot control valve to be incorporated directly into the end of the logic cartridge via the T-8A cavity. These pilot control cartridges are
sold separately and include electro-proportional, solenoid, air pilot, and hydraulic pilot operation. See Pilot Control Cartridges.
These valves open quickly when vented. Time to close is difficult to predict as it is dependant on the rate of flow and the pressure drop created as it closes.
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%.
Compound cartridge (pilot and main stage) assembly information is provided for reference only. Cartridges must be ordered separately and assembled at
point of use.
NOTES
Model Code Example: LOHA8DNCONFIGURATION OPTIONS