Oil lance UNIGRESS ZL for kiln firing systems

NO NOZZLE CHANGE from start up to full load

The UNIGRESS ZL high pressure fuel atomizer lances are designed for regular forward flow but also for the more professional forward/return flow control mode.

This enables kiln burner oil operation without nozzle change due to a total control range of 1 : 8 on forward/return flow control mode. Precondition: Also the fuel oil valve train (as control unit) must be designed to be operated in forward/return flow control mode as Unitherm Cemcon provides.

Forward flow operation
→ mode for normal burner operation with high burner capacity.

In this mode the fuel oil enters the oil lance through both the axial oil connection and the radial oil connection, and is thus fed through both channels into the lance nozzle. In forward flow operation the oil is fed parallel to the atomiser nozzle (radial and axial). (When the fuel oil valve train is not designed for return flow operation a nozzle change is necessary for lower load.)

Return flow operation
→ a special mode for start up and low burner capacity.

In this mode the oil lance operates as a return flow lance, i.e. fuel oil only enters the oil lance through the radial oil connection and is fed to the burner nozzle via the radial oil channel. Excess oil is then returned to the axial oil connection of the oil lance via the axial channel. Return flow back to tank separately is controlled with a control valve on valve train. (Return flow operation is only possible when the fuel oil valve train is designed therefore.)

A special feature of the UNIGRESS ZL oil lance is the manual adjustable piston to shut or open radial slots situated on the nozzle insert for radial oil.

This sophisticated design enables:
a total control range of 1 : 15 and a possibility for flame shape adjustment on forward flow mode.
» Adjusting of the slot height by internal lance piston
» Scale for adjustable piston
» Radial oil connection
» Axial oil connection


UNIGRESS ZL 4001 ZL 8001 ZL 10001 ZL 15001 ZL
Max. flow in kg/hr 4000 8000 10000 15000
Max. flow in lb/h 8800 17600 22000 33000
Lance guiding tube Ø 76,1 mm/2,5” 88,9 mm/3” 88,9 mm/3” 114,3 mm/4”
Atomising viscosity up to 20 cSt
Pressure range 9 bar - 36 bar / 130 psi - 522 psi

Above flows refer to heavy fuel oil (fuel oil #6)

Performance example:
Heavy fuel oil, 15 cSt at 130°C, 330 - 5000 l/hr, UNIGRESS 8001 ZL

Forward flow operation: 5000 - 1600 l/h 1 : 3 (1 : 3,1) normal burner operaton
Return flow operation: 2000 - 625 l/h 1 : 8 (1 : 3,2) start up burner operation
Return flow operation + 
adjustable slots height:
800 - 330 l/h 1 : 15 (1 : 2,4) drying operation
Total control range: 5000 - 330 l/h 1 : 15   without nozzle changing