Its the distance from piston back, to piston out
Unequal
Reciprocating compressors are either single- or double-acting. In single-acting machines the compression takes place on only one side of the piston; double-acting machines use both sides of the cylinder for compression.
double acting pump. .to a maximum when the piston is approximately halfway through its stroke. The variation in pumping rate can be reduced by using both sides of the piston to pump fluid. Pumps of this type are called double acting. Fluctuations in pumping rate can be further reduced by using more than one cylinder.
An opposed piston engine is a single-acting engine. All modern gasoline and diesel engines are single-acting. The single-acting engine receives force on one side of the piston, and relies on the engine to push the piston back the other way. On an opposed engine like a Continental or Lycoming, the piston on the other side of the engine will do the pushing. A double-acting engine, which almost always means a steam engine, receives force on both sides of the piston. Since they run horizontally, when the piston is to the right the engine will send steam to push it to the left and when it's to the left the engine will send steam to push it to the right. A slide valve decides which side of the piston the steam will go to.
single acting: actively driven by hydraulic fluid pressure in only one direction, passively returned in the other direction by another force (e.g. springs, gravity)double acting: actively driven hydraulic fluid pressure in both directions
Single Acting Cylinders:In single acting cylinders the fluid is pressurized from only one side of the cylinder during both the expansion as well as the retraction process.Double Acting Cylinders:In the double acting cylinders, the pressure from the fluid is applied in both the directions.Any double-acting cylinder may be used as a single-acting unit by draining the inactive end.By hamza_siddiqui@hotmail.com
The driving force action on the piston is called piston effort.In other words the net resultant of all the other forces acting on the piston is called piston effort.
Single-acting devices consist of a large plunger, or piston, into which oil (or air in a pneumatic cylinder) is pumped.
working of single acting and double acting cylinder
The working pressure acts from one side in single acting actuators while in double acting actuators strokes generating by each side.
Here are the ingredients for double-acting baking powder -- if yours has these ingredients, then it's double-acting. (My can of Kroger baking powder is.) Double Acting Baking Powder Ingredients: Corn Starch Bicarbonate of Soda Sodium Aluminum Sulfate Acid Phosphate of Calcium