HP – pumps with a single ended intensifier are identically designed as the double acting ones but they only have one HP – barrel.
The single ended intensifier is operated by the same hydraulic system and has an identical control. The missing second barrel makes the pump a little cheaper. As the hydraulic piston has to be reversed after the load stroke, the pump needs the same oil volume as a double acting type.
Pumps with single ended intensifiers are not very common.

Much more important are singe shot intensifier. These intensifiers do not have inlet and outlet valves. They are directly linked to the pressure vessel.
The discharge volume of a single shot intensifier has to be so large, that the final pressure in the pressure vessel can be achieved by one stroke only. Reversing the stroke of the hydraulic piston reduces the pressure again to zero. This special arrangement allows the application of this type intensifier for extremely high pressures. No let down valves for the high pressures are required.
Pressure increase and decrease can be controlled by using an axial piston pump with variable flow. The pressure then exactly can be controlled by an electrical signal which is proportional to the pressure. The speed of building up the pressure in the vessel depends on the power input of the machine.
Single shot intensifiers are used for isostatic compaction of powder or in food processing.