Pipe Heating System; Inlet Minimum Pressure Of The Pump (Both For Supplying System And Burner); Pump Operating Maximum Pressure (Both For The Supplying System And Burner); Adjusting The Supplying Oil Ring - Unigas PN91 Manual Of Installation - Use - Maintenance

Pipe heating system

Pipe heating system must be provided, that is a system to heat pipes and plant components to mantain the viscosity in the pumping lim-
its. Higher the oil viscosity and lower the ambient temperature, more necessary the pipe heating system.

Inlet minimum pressure of the pump (both for supplying system and burner)

A very low pressure leads to cavitation (signalled by its peculiar noise): the pump manifacturer declares the minimum value. Therefore,
check the pump technical sheets.
By increasing the oil temperature, also the minimum inlet pressure at the pump must increase, to avoid the gassification of the oil low-
boiling products and the cavitation. The cavitation compromises the burner operation, it causes the pump to break too. The diagram on
Fig. 11 roughly shows the inlet pump pressure according to the oil temperature.

Pump operating maximum pressure (both for the supplying system and burner)

Remember that pumps and all the system components through which the oil circulates, feature an upper limit. Always read the techni-
cal documentation for each component. Schemes on Fig. 13 and Fig. 14 are taken from UNI 9248 "liquid fuel feeding lines from tank to
burner" standard and show how a feeding line should be designed. For other countries, see related laws in force. The pipe dimensio-
ning, the execution and the winding dimensioning and other construcitve details must be provided by the installer.

Adjusting the supplying oil ring

According to the heavy oil viscosity used, in the table below indicative temperature and pressure values to be set are shown.
Note: the temperature and pressure range allowed by the supplying ring components must be checked in the specifications table of the
components themselves.

Burner adjustments

The table below shows indicative values of temperature and pressure to be set on the burner devices, according to the viscosity of the
heavy oil used. The oil temperature should be set on TR resistor thermostat in order to get about 1.5°E viscosity at the nozzle.
VISCOSITY
AT 50 °C
cSt (°E)
< 50 (7)
> 50 (7) < 110 (15)
> 110 (15) 400 (50)
VISCOSITY
AT 50 °C
cSt (°E)
< 50 (7)
> 50 (7) < 110 (15)
> 110 (15) 400 (50)
*
C.I.B. UNIGAS - M039196CC
HEAVY OIL VISCOSITY AT 50 °C
cSt (°E)
> 50 (7) < 110 (15)
> 110 (15) < 400 (50)
RETURN
NOZZLE
NOZZLE
PRESSURE
PRESSURE
MEASURED IN
THE GUN
min. max.
bar bar
25 7-9 19-20
25 7-9 19-20
25 7-9 19-20
Tab. 1 - Fluidics WR2 nozzle
RETURN
NOZZLE
NOZZLE
PRESSURE
PRESSURE
MEASURED IN
THE GUN
min. max.
bar bar
20 5-7 11-13
20 5-7 11-13
20 5-7 11-13
Tab. 2 - Bergonzo A3 nozzle
PIPELINE
PRESSURE
bar
< 50 (7) 1- 2
1- 2
1- 2
TEMPERATURE ON TEMPERATURE
THE PRE-HEATING
RESISTORS RESISTORS
THERMOSTAT
min. max.
°C
100 115
125 140
145 160
TEMPERATURE ON TEMPERATURE
THE PRE-HEATING
RESISTORS RESISTORS
THERMOSTAT
min. max.
°C
100 115
125 140
145 160
14
PIPELINE
TEMPERATURE
°C
20
50
65
TEMPERATURE
OF THE
ON THE OIL
ENABLING
SAFETY
THERMOSTAT
TCN
TRS
°C °C
170 80
190 100
190 110
TEMPERATURE
OF THE
ON THE OIL
ENABLING
SAFETY
THERMOSTAT
TCN
TRS
°C °C
170 80
190 100
190 110
TEMPERATURE
ON THE PLANT
ENABLING
THERMOSTAT
TCI
°C
50 - 60
60 - 80
70 - 90
TEMPERATURE
ON THE PLANT
ENABLING
THERMOSTAT
TCI
°C
50 - 60
60 - 80
70 - 90