Mr. CSHOF with appreciation a reply on air cylinder pressure computation Thanks for the commemnt Mr. CSHOF.
I certainly could have gone into more detail that would have been clearer and the truth is you are not exactly right or wrong on all points but your final pressure computations would not be correct as per the further provenance I submit below. If your force calculations were correct the force at the injection site would by about 3 bags of sugar (harmless) but I would not reccomend a test with your hand or it would likely punch a hole right through it. Please bear with me a few paragraphs.
Disclaimers: As per another commenter warning of exploding brain syndrome from this kind of article,If anyone is susceptible please avert your eyes now or you will go gronk!
Also for anyone and especially the helpful and concerned Mr. CSHOF: If you think my my goal here is to put on "airs" (pun intended) remember I have allowed myself to be abused by dentists for 36 years so I can't be all that smart.
Mr. CSHOF,
The comparison of liquid and gaseous working fluids requiring single or multiple cylinders such as a master and slave or working piston and air reservoir are a bit of apples and oranges unless the equipment is exactly mechanically the same piece-by-piece for both devices you are comparing.For instance, dental presses do not have a master cylinder with its own diameter,pressure and working rod diameter, not to mention the "reservoir" is pressurized only by your foot or an assist and limited to its working design.
Although both air and oil are fluids in the exact sense, oil is basically uncompressable as a (ambient)liquid and a slave to the master cylinder initial pressure (no pun intended but it is a good one...) and the final working connection is going to be a composite of the master and slave as well as the rod size and is not directly applicable to air (at ambient a gas not a liquid) cylinders where the working fluid is very compressable. I used the steam rough comparison (adding unnecesary complexity) because although ambient temp. water is like oil in not being hardly compressable, when it turns to steam it is compressable and force computations are done basically as air.
Of course if you overheat your brake fluid and it turns to a spongy gas or you use liquid oxygen instead of gaseous air the roles then reverse...I'm sorry I brought it up, let's not go there!
Anyhow following is an article from google (EHOW) I reprint because coincidentally the diameter/pressure #s are close and I shouldn't requote myself. This article is for air but in a general sense any fluid as you can read at the end.
One thing to mention where you were not wrong... and that is for the most precise result the size of the rod IS a small but real factor depending on the size of the rod (usually a small percentage but not nercessarily if the rod is the size of the piston)... but neverless a real factor that I did not mention for simplicity but from this article you can see you have a valid point.
Unrelated: I have gotten some more Dentsply feedback but more is expected shortly as well as the results of a few more experiments.
Thanks Mr. CSHOF for the reply. See if you can guess what hydraulic mischief the attached photos are. Here is the article for provenance:
How to Calculate Pneumatic Cylinder Force ( eHow.com )
Read more: How to Calculate Pneumatic Cylinder Force | eHow.com
How to Calculate Pneumatic Cylinder Force | eHow.com G.K. Bayne is a freelance writer for various websites, specializing in back-to-basics instructional articles on computers and electrical equipment. Bayne began her writing career in 1975 and studied history at the University of Tennessee. By G.K. Bayne, eHow Contributor
Pneumatic cylinders are used widespread in industry for repetitive motion in the manipulation of objects. Whether that object is being pushed or pulled, that cylinder must have enough force in order to efficiently move the object. All air pressure is measured in pounds per square inch (PSI),and by following a basic process you can calculate the total force that a pneumatic cylinder can deliver.
Instructions
1.
o 1
Measure the size of the air cylinder to calculate the total area that the air will be pushing against to create the force. All pneumatic cylinders are classified by the diameter of the cylinder and the length of the stroke. The most important measurement we need in calculating force is the diameter of the cylinder.
o 2
Find the total area in the pneumatic cylinder if the diameter is 4 inches. To find the area of a round circle for any object, the formula is A= (pi) x (Rsquared). Where A is equal to area, pi is equal to 3.1416 and Rsquared is the radius of the circle squared.
o 3
Calculate the area of the 4-inch diameter circle by first multiplying the radius times itself. This would equal 2 inches as the radius, times itself or 2 X 2 is equal to 4. Next multiply pi (3.1416) times the 4 and the answer is 12.5664 square inches. So the total area of the air cylinder is equal to 12.5664 inches^2, read as inches squared.
o 4
Find the total force from the air cylinder if the air pressure is equal to 100 PSI. Since PSI is equal to pounds per square inch, all we need to do is multiply the total area in square inches of the pneumatic cylinder times the air pressure in PSI. The total force delivered from the 4-inch diameter air cylinder with 100 PSI of air pressure would equal 12.5664 inches^2 times 100 PSI, which is equal to 1,256.4 pounds of force.
o 5
Understand that the 1,256.4 pounds of force would be on the push stroke only and not on the retraction end of the cylinder. The diameter of the push rod must be subtracted from the overall area, as the connection of the push rod interferes with the force measurement.
o 6
Find the area of the push rod for the retraction force measurement if the push rod is 2 inches in diameter. Using the formula from Step 3, the area of the push rod would be A = (3.1416) times 1^2, which is equal to 3.1416 square inches. Subtract 3.1416 from 12.5664 and the resultant area on the retraction stroke of the pneumatic cylinder would be equal to 9.4248 square inches. If the air pressure remains the same, at 100PSI, then the force would be equal to 942.48 pounds of force.
Tips & Warnings
• Any size cylinder can be calculated using the formula above. This includes hydraulic cylinders, as well. You only need to know the total pressure that the hydraulic system will deliver to the cylinder.
Read more: How to Calculate Pneumatic Cylinder Force | eHow.com
How to Calculate Pneumatic Cylinder Force | eHow.com See photo attachments if you wish. See if you can guess what hydraulic mischief the attached photos are.