Method for adjusting a mechanical natural frequency

A method for adjusting a mechanical natural frequency of a measurement pickup including a pickup housing forming a first hollow body of the measurement pickup, and a measurement pipe forming a second hollow body of the measurement pickup, the measurement pipe being mounted within the pickup housing and the measurement pipe being adapted for carrying a medium to be measured, and at least one of the first and second hollow bodies at least partly comprises a ductile material, said method including the steps of:

• adjusting a mechanical natural frequency of the pickup housing;
• varying a static external pressure of an atmosphere surrounding the pickup housing, and/or varying a static internal pressure prevailing in a substantially pressure tight-sealed lumen of the pickup housing, for generating a pressure difference between the lumen and the atmosphere surrounding the pickup housing;
• adjusting the pressure difference to a value that causes the ductile material of the pickup housing to expand;
• and
• causing at least a portion of the ductile material of the pickup housing to flow under the influence of the pressure difference for plastically deforming the ductile material, wherein:
• said step of causing at least a portion of the material of said pickup housing to flow under the influence of the pressure difference for plastically deforming the material is effected without additional heating of the material, and/or said step of causing at least a portion of the material of said pickup housing to flow under the influence of the pressure difference for plastically deforming the material is effected below a temperature of recrystallization of said material.

A method for providing a measurement pickup including a pickup housing, the pickup housing is formed as a hollow body at least partly comprising a ductile material, said method including the steps of:

• increasing a static rigidity of the pickup housing;
• varying a static internal pressure prevailing in a substantially pressure tight-sealed lumen of the pickup housing, for generating a pressure difference between the lumen and a atmosphere surrounding the pickup housing;
• adjusting the pressure difference to a value that causes the ductile material of the pickup housing to expand;
• causing at least a portion of the ductile material of the pickup housing to flow under the influence of the pressure difference for plastically deforming the ductile material,
• said step of causing at least a portion of the ductile material of the pickup housing to flow under the influence of the pressure difference for plastically deforming the ductile material is effected without additional heating of the ductile material;
• and/or
• said step of causing at least a portion of the ductile material of the pickup housing to flow under the influence of the pressure difference for plastically deforming the ductile material is effected below a temperature of recrystallization of the ductile material.

A method for providing a measurement pickup including a pickup housing, the pickup housing is formed as a hollow body at least partly comprising a ductile material, said method comprising the step of

• pressure testing the pickup housing, including the following steps of:
• varying a static internal pressure prevailing in a substantially pressure tight-sealed lumen of the pickup housing, for generating a pressure difference between the lumen and a atmosphere surrounding the pickup housing;
• adjusting the pressure difference to a value that causes the ductile material of the pickup housing to expand;
• and
• causing at least a portion of the ductile material of the pickup housing to flow under the influence of the pressure difference for plastically deforming the ductile material, wherein:
• said step of causing at least a portion of the ductile material of the pickup housing to flow under the influence of the pressure difference for plastically deforming the ductile material is effected without additional heating of the ductile material;
• and/or
• said step of causing at least a portion of the ductile material of the pickup housing to flow under the influence of the pressure difference for plastically deforming the ductile material is effected below a temperature of recrystallization of the ductile material.