Method for producing seamless pipe

• US 3,228,075 A
• Filed: 03/19/1963
• Issued: 01/11/1966
• Est. Priority Date: 04/28/1958
• Status: Expired due to Term

• Current Assignee: Hans Lindemann
• Original Assignee: Hans Lindemann
• Inventors: Lindemann, Hans
• Application Number:
  US04/266,424
• Time in Patent Office: 1,029 Days
• US Class Current: 164/465
• CPC Class Codes: B21C 23/085 Making tubes B21C23/10 take precedence
• CPC Class Codes: B21C 29/00 Cooling or heating work or parts of the extrusion press; Gas treatment of work
• CPC Class Codes: B22D 11/006 of tubes

Claims

1. AN EXTRUSION METHOD COMPRISING, IN COMBINATION, THE STEPS OF HEATING A MATERIAL AT LOW PRESSURE TO A HIGH TEMPERATURE AT WHICH THE MATERIAL IS IN THE LIQUID STATE, SAID MATERIAL BEING OF SUCH A NATURE AS TO SOLIDIFY AT SAID LOW PRESSURE AND AT A LOWER TEMPERATURE;

REDUCING THE TEMPERATURE OF THE MATERIAL IN A CLOSED CONTAINER TO A SELECTED LOWER TEMPERATURE WHILE SIMULTANEOUSLY INCREASING THE PRESSURE IN THE CONTAINER;

ADJUSTING THE PRESSURE IN THE CONTAINER TO A PREDETERMINED PRESSURE AT WHICH THE MATERIAL IS ADAPTED TO FLOW AT SAID SELECTED TEMPERATURE, BUT WHICH PREDETERMINED PRESSURE IS SELECTED SO THAT EVEN A SMALL REDUCTION OF SAID PREDETERMINED PRESSURE TO A SLIGHTLY REDUCED PRESSURE WOULD CAUSE THE MATERIAL TO SOLIDIFY AT SAID SELECTED TEMPERATURE;

AND DISCHARGING THE MATERIAL AT SAID PREDETERMINED PRESSURE AND SELECTED TEMPERATURE FROM SAID CONTAINER THROUGH AN EXTRUSION NOZZLE INTO A SPACE HAVING A PRESSURE SUBSTANTIALLY LOWER THAN SAID SLIGHTLY REDUCED PRESSURE SO THAT THE DISCHARGED MATERIAL MOMENTARILY SOLIDIFIES DUE TO THE SUBSTANTIAL PRESSURE REDUCTION.