Gas flowmeter

1. A gas flowmeter comprising:

a body having a transparent inner, rotameter tube sealed thereto that forms a pressurized passage that communicates with an inlet and an outlet for receiving gas flow therethrough;

a transparent, second tube that is secured and sealed at a first end to the body and has a second end that sealingly receives a cap, the transparent second tube coaxially receiving the rotameter tube therein to form a pressure chamber that also receives the gas flow therethrough;

a transparent unpressurized outer cover having first and second ends, the transparent outer cover coaxially received around both the rotameter tube and the transparent second tube, the transparent outer cover mounted for rotation relative to the body at the first end and relative to the cap at the second end;

a selectively variable valve that controls the gas flow to the outlet;

first, second, third, and fourth calibrated scales fixed to the outer cover and that represent a flow rate of one of at least first, second, third, and fourth different types or mixtures of gases, respectively, through the passage in the rotameter tube; and

first and second floats having different material properties received in the passage of the rotameter tube and viewable through the transparent second tube and the outer cover in operative association with the calibrated scales, the first float having a first density operatively associated with the first calibrated scale to monitor gas flow of the first gas when the first gas flows into the body, and the second float having a second density greater than the first density of the first float and operatively associated with one of the second, third, and fourth calibrated scales to monitor gas flow of one of the second, third, and fourth different gases different than the first gas when one of the second, third, and fourth different gases flows into the body.

2. The gas flowmeter of claim 1 wherein the first and second floats have different colors so that an associated user can monitor the gas flow of the different types or mixtures of gases flowing through the passage via select ones of the calibrated scales.

3. The gas flowmeter of claim 1 wherein the calibrated scales are configured for selective display as selected by an associated user.

4. The gas flowmeter of claim 3 wherein the calibrated scales are provided on an inner surface of the outer cover mounted to the body and surrounding the passage.

5. The gas flowmeter of claim 4 further comprising a drag member that applies a predetermined friction force between the outer cover and the body.

6. The gas flowmeter of claim 1 wherein the calibrated scales are non-linear.

7. A method of forming a gas flowmeter comprising:

providing a body having a transparent inner, rotameter tube with a passage that communicates with an inlet and an outlet for receiving gas flow therethrough;

providing a transparent, second tube that is secured at a first end to the body and has a second end that receives a cap, the transparent second tube receiving the rotameter tube therein in a sealed relation to form a pressurized chamber, the transparent second tube also receiving the gas flow therethrough;

providing a transparent unpressurized outer cover received around the transparent second tube and that is configured for rotation relative to the rotameter tube, transparent second tube, cap, and body;

controlling the gas flow to the outlet with a valve; and

incorporating first, second, third, and fourth calibrated scales secured to an inner surface of the transparent outer cover to monitor flow rates of one of at least first, second, third, and fourth different types or mixtures of gases, respectively, through the passage; and

using first and second floats having different densities in the passage and viewable in operative association with the calibrated scales, the first float having a first density associated with the first calibrated scale to monitor gas flow of the first gas, and the second float having a second density greater than the first density where the second float is associated with one of the second, third, and fourth calibrated scales to monitor gas flow of one of the second, third, and fourth different gases.

8. A gas flowmeter comprising:

a body having a transparent inner, rotameter tube with a passage that communicates with an inlet and an outlet for receiving gas flow therethrough, the transparent rotameter tube received in a transparent, second tube that is sealed at a first end to the body and has a second end that sealingly receives a cap to form a pressurized chamber, and a transparent unpressurized outer cover received around the transparent second tube;

a selectively variable valve that controls the gas flow to the outlet; and

at least first, second, third, and fourth calibrated scales viewable through the transparent outer cover to represent a flow rate of one of first, second, third, and fourth different types or mixtures gases, respectively, through the passage, wherein the first, second, third, and fourth calibrated scales are located on the transparent outer cover and the transparent outer cover is mounted for rotation relative to the cap and body; and

first and second floats having different densities received in the passage and viewable in operative association with the calibrated scales, the first float operatively associated with the first calibrated scale to monitor gas flow of athe first gas, and the second float operatively associated with one of the second, third, and fourth scales to monitor gas flow of one of the second, third, and fourth different gases different than the first gas when one of the second, third, and fourth different gases flows through the body.

9. The gas flowmeter of claim 8 wherein the first and second floats have different colors so that an associated user can monitor the gas flow of the different types or mixtures of gases flowing through the passage via select ones of the calibrated scales.

10. The gas flowmeter of claim 8 wherein the calibrated scales are secured to an inner surface of the transparent cover.