Hydraulic Valve Types: Directional, Relief & Tipping

A hydraulic valve controls the direction, pressure and flow of oil in a hydraulic system. The pump creates flow and the cylinder does the work, but the valves decide which movement happens, when, how fast and with how much force. There are three main groups: directional control, pressure control and flow control valves.

Types of Hydraulic Valves

1. Directional control valves

Route oil to extend, retract or hold a cylinder.

Actuation: manual lever, pneumatic, electric (solenoid) or hydraulic pilot
Design: spool or poppet
Typical use: construction machinery, tippers, cranes, agricultural equipment

2. Pressure control valves

Relief valve: dumps oil to tank above the set pressure, protecting pump, hoses and cylinder. Every hydraulic system needs one.
Pressure reducing valve: runs part of the circuit at lower pressure.
Sequence valve: starts a second movement after the first is complete.
Counterbalance (load holding) valve: prevents a suspended load from dropping uncontrolled.

3. Flow control valves

Throttle valve: simple speed adjustment
Pressure-compensated flow control: keeps speed constant as load changes
Flow divider: splits flow between two circuits

4. Check valves

Allow flow in one direction only. Pilot-operated check valves lock a cylinder in position.

What Does 4/3 Mean?

The first number is the number of ports, the second the number of positions.

Symbol	Ports	Positions	Typical use
2/2	2	2	On / off
3/2	3	2	Single acting cylinder (lift / lower)
4/2	4	2	Double acting cylinder (extend / retract)
4/3	4	3	Double acting cylinder (extend / hold / retract)

On 4/3 valves the centre type (closed, open or tandem) matters: open and tandem centres unload the pump to tank in neutral, reducing heat and energy loss.

How Does a Tipping Valve Work?

A tipping valve is a directional valve designed for tipper trucks and trailers. It controls lifting, holding and lowering the body, usually with a single acting telescopic cylinder.

Lift: pump flow goes to the cylinder
Hold: the cylinder line is closed and pump flow returns to tank
Lower: oil flows from the cylinder back to tank in a controlled way

Most tipping valves are pneumatically operated from the cab and include a built-in relief valve. They can be mounted directly on the pump or as a separate block.

How to Choose a Hydraulic Valve

Flow: rated flow equal to or above pump flow
Pressure: maximum rating above system pressure
Function: 3/2 for single acting, 4/3 for double acting cylinders
Actuation: pneumatic from the cab, electric remote or manual lever
Voltage: 12 V / 24 V coils for solenoid valves
Ports: BSP, SAE etc. matching hoses and pump
Relief setting: matched to cylinder and pump limits

Signs of Valve Failure

Slow cylinder: low relief setting or internal leakage
Body will not lower: blocked return line or faulty air control
Body creeps down: spool leakage
Overheating: undersized valve or relief valve constantly opening
Sticking spool: contaminated oil

Hypo Hydraulic Valves

Özceylanlar (Hypo Hydraulic), founded in 1974 in Konya, Turkey, produces around 20,000 circuit components, 25,000 pumps and 20,000 cylinders a year and exports about 90% of its output.

Valves and hydraulic control components for tipping applications
Tested system solutions matched to our pumps, cylinders and PTOs
ISO 9001, CE, TS 11552 and RINA ISO 3834-2
Complete tipping kits from one supplier, with OEM options

Hydraulic Valve Types and How to Choose a Tipping Valve