Volume calibration syringe

In a gas volume calibration syringe of the type including a housing having a central section and first and second end sections, a piston slidably mounted in the central section, and a shaft attached to the piston and slidably mounted in the first end section, the improvement comprising:

• (a) latching means for establishing a predetermined first end position for the piston in the vicinity of the first end section, said second end section serving to establish a predetermined second end position for the piston,
• (b) spring loaded means for driving the piston between its first and second end positions, and
• (c) a release member for controllably releasing said latching means and thereby initiating an ejection stroke of the piston, and wherein the second end section is fluidically connected to a gas measuring instrument and a source of calibration gas.

A gas volume calibration syringe of the type including a housing having a central section and first and second end sections, a piston slidably mounted in the central section, a shaft attached to the piston and slidably mounted in the first end section, the improvement comprising:

• (a) a gas outlet in the second end section for connection to a gas analysis instrument,
• (b) a separate gas inlet in the second end section for connection to a source of calibration gas, and
• (c) means for selectably controlling the rate at which ambient air can flow into the syringe to occupy the space behind the trailing surface of the piston during ejection.

A gas volume calibration syringe of the type including a central section and first and second end sections, a piston slidably mounted in the central section, a shaft attached to the pistion and slidably mounted in the first end section, the improvement comprising:

• (a) a gas inlet in the second end section connected to a gas analysis instrument, and
• (b) a separate gas inlet in the second end section connected to a source of calibration gas.
• (c) a means for driving the piston during at least the ejection stroke thereof.

A calibration syringe comprising a housing having a central section, a first and second end section, a piston slidably mounted in said central section, a shaft attached to said piston and slidably mounted in said first end section, a spring loaded means for moving said piston away from said first end section and towards said second end section, and a restriction means for controlling the rate of flow of gas into said housing between said first end section and said piston to provide a method for varying the speed of movement of said piston.