Method of manufacturing orifice

A method of manufacturing an orifice, the method comprising:

• a body portion preparing step of preparing a body portion in which a hollow having a circular cross section is formed;
• a stress value calculating step of calculating a stress value required for a predetermined desired flow rate value according to the following relationship equation between a flow rate and a stress:
• S
• =
• 1
• C
• 2
• ⁢
• ln
• ⁡
• (
• m
• .
• C
• 1
• )
• ,
• wherein {dot over (m)} is the flow rate (g/s), S is the stress (N/m2), C1 is a positive constant (g/s), and C2 is a negative constant (m2/N);
• and
• a pressed portion manufacturing step of manufacturing a pressed portion in which the hollow becomes a slit by pressing at least a partial region of the body portion with a pressing force corresponding to a value of the stress calculated in the stress value calculating step,
• wherein
• in the stress value calculating step, a value of C1 is 4.0437 and a value of C2 is −3*10−9,
• in the pressed portion manufacturing step, an area value of the pressed portion is calculated according to the following relationship equation:
• A
• =
• WL
• =
• (
• 2
• t
• +
• π
• ⁢
• D
• i
• 2
• )
• ⁢
• L
• ,
• wherein A is an area (m2) of the pressed portion, W is a width (m) of the pressed portion, L is a length (m) of the pressed portion, t is a thickness (m) of a wall of the body portion, and Di is an inner diameter (m) of the body portion, and
• the pressing force is calculated from the following relationship equation:
• F=SA,
• wherein F is the pressing force (N), S is the Stress (N/m2), and A is the area (m2) of the pressed portion.