Tank for holding contents which can separate into different phases

1. A tank ( 1 ; 1 ′; 20 ) for holding contents which can separate into different phases, said tank having at least one side wall between an opposed top and bottom thereof, being a metallic or a plastic tank and comprising:

at least two outlet pipes ( 3 , 5 ; 23 , 25 , 26 ) each provided through the bottom of the tank with a first end ( 3 a , 5 a ; 23 a , 25 a , 26 a ) of the outlet pipes provided outside the tank and a second end ( 3 b , 5 b ; 23 b , 25 b , 26 b ) provided inside the tank, the second ends of the at least two outlet pipes being provided at different heights within the tank,

at least one content filling pipe ( 35 ) comprising a perforated pipe ( 37 ) perforated with holes along its length, said perforated pipe being provided on the inside of the tank along substantially the whole length of the tank in a direction extending between the opposed top and bottom,

the content filling pipe further comprises a connection pipe ( 39 ) extending substantially in said direction, connected close to an open top end ( 40 ) of the perforated pipe ( 37 ) and provided through the bottom of the tank and inside the tank, and

a heater ( 45 ) provided in the tank for heating the content.

2. A tank according to claim 1 , wherein the content is slop oil, industrial emulsions or industrial oils.

3. A tank according to claim 1 , further comprising:

at least one sensor ( 31 ) arranged for detecting an interface between two phases of the content in the tank.

4. A tank according to claim 3 , wherein the sensor is a guided wave radar and can detect an interface between water and oil.

5. A tank according to claim 3 , further comprising a control system ( 19 ) arranged to control an outtake of content from the tank through the at least two outlet pipes in dependence of output from the at least one sensor.

6. A tank according to claim 1 , wherein said tank further comprises connection pipes ( 11 a , 11 b ) connected to the outlet pipes ( 3 , 5 ), and at least one of said connection pipes ( 11 a , 11 b ) comprises a sensor ( 13 a , 13 b ).

7. A tank according to claim 1 , further comprising a layer of insulation around the tank.

8. A tank according to claim 1 , wherein the heater ( 45 ) is a tube coiled around the bottom part of the tank ( 20 ).

9. A tank according to claim 1 , additionally comprising a third outlet pipe ( 26 ), with said first respective ends ( 23 a , 25 a , 26 a ) of all said three outlet pipes ( 23 , 25 , 26 ) provided outside the tank, said second respective ends ( 23 b , 25 b , 26 b ) of all said three outlet pipes ( 23 , 25 , 26 ) provided inside the tank, and said second respective ends ( 23 b , 25 b , 26 b ) of all said three outlet pipes ( 23 , 25 , 26 ) being provided at different heights within the tank from one another.

10. A tank according to claim 1 , wherein said pipes ( 23 , 25 ) are oriented vertically inside said tank and said first respective ends ( 3 a , 5 a ; 23 a , 25 a , 26 a ) of said outlet pipes ( 23 , 25 ) each extending vertically through the bottom ( 7 ) of said tank.