An apparatus for the production of foamed glass, comprising a. A dosing chamber for receiving a glass mixture, said glass mixture comprising crushed or ground glass mixed with a foaming agent, b. A sluice chamber arranged to receive a volume of glass mixture from the dosing chamber, said sluice chamber being separated from the dosing chamber by a first closable valve, said sluice chamber further comprising a pressure source (4,5), said pressure source arranged to apply a positive operating pressure, c. A feed chamber comprising a pressure vessel arranged to receive a volume of glass mixture under pressure from the sluice chamber, said feed chamber separated from the sluice chamber by a second closable valve, said feed chamber comprising a pressure source arranged to apply a pressure equal to the operating pressure, and a feed device, d. An extruder chamber arranged to receive a volume of glass mixture from the feed chamber via the feed device, said extruder chamber being subjected to the positive operating pressure and comprising a heat source (28.1, 28.2) arranged to raise the temperature of the interior of the extruder chamber to an operating temperature at which the crushed or ground glass melts, and which activates the foaming agent, thereby forming a viscous foamed glass material, e. A nozzle section comprising a chamber (26.1) arranged at an end of the extruder chamber, arranged for receiving the viscous foamed glass material from the extruder chamber under influence of the positive operating pressure, said nozzle section comprising one or more nozzles at an end of the nozzle section, through which the viscous foamed glass material may exit under influence of the positive operating pressure, wherein the extruder chamber comprises an inner extruder pipe and a concentrically arranged outer extruder pipe, together defining an annular space for receiving the glass mixture from the feed device, and further wherein the heat source of the extruder chamber comprises one or more induction coils arranged for heating the inner and outer extruder pipes. a. A dosing chamber for receiving a glass mixture, said glass mixture comprising crushed or ground glass mixed with a foaming agent, b. A sluice chamber arranged to receive a volume of glass mixture from the dosing chamber, said sluice chamber being separated from the dosing chamber by a first closable valve, said sluice chamber further comprising a pressure source (4,5), said pressure source arranged to apply a positive operating pressure, c. A feed chamber comprising a pressure vessel arranged to receive a volume of glass mixture under pressure from the sluice chamber, said feed chamber separated from the sluice chamber by a second closable valve, said feed chamber comprising a pressure source arranged to apply a pressure equal to the operating pressure, and a feed device, d. An extruder chamber arranged to receive a volume of glass mixture from the feed chamber via the feed device, said extruder chamber being subjected to the positive operating pressure and comprising a heat source (28.1, 28.2) arranged to raise the temperature of the interior of the extruder chamber to an operating temperature at which the crushed or ground glass melts, and which activates the foaming agent, thereby forming a viscous foamed glass material, e. A nozzle section comprising a chamber (26.1) arranged at an end of the extruder chamber, arranged for receiving the viscous foamed glass material from the extruder chamber under influence of the positive operating pressure, said nozzle section comprising one or more nozzles at an end of the nozzle section, through which the viscous foamed glass material may exit under influence of the positive operating pressure, wherein the extruder chamber comprises an inner extruder pipe and a concentrically arranged outer extruder pipe, together defining an annular space for receiving the glass mixture from the feed device, and further wherein the heat source of the extruder chamber comprises one or more induction coils arranged for heating the inner and outer extruder pipes.