The pump designation is part of API Spec 11AX and describes the main specifications of an API subsurface pump. It is a nomenclature to classify API sucker rod pumps and tubing pumps according to their main characteristics. It is comprised of seven parts, separated by dashes.
Example: 20-125-RHBC-10-4-2-2
Each part, in order, describes the following specifications:
- Nominal tubing size (inch – given as a key representing the actual size)
- Basic bore size (inch)
- Type of pump, type of barrel, location and type of seating assembly (letter code)
- Barrel length (ft)
- Plunger length (ft)
- Length of upper extension, used with heavy-wall barrel (inch)
- Length of lower extension, used with heavy-wall barrel (inch)
Example: A 1 1⁄4 in. (31.8 mm) bore rod type pump with a 10 ft (3.048 m) heavy wall barrel and 2 ft (0.610 m) upper extension, 2ft (0.610 m) lower extension, a 4 ft (1.219 m) plunger, and a bottom cup type seating assembly for operation in 2 3⁄8 in. (60.3 mm) tubing, would be designated as follows:
