A fluid pump may include a fluid chamber, a plunger configured to reciprocate within the fluid chamber, and a valve system including multiple valves. The multiple valves each may be configured to control fluid flow into the fluid chamber or each may be configured to control fluid flow out from the fluid chamber.

A pressure amplifier (1) is described comprising a housing (2), an amplification piston (5) in the housing (2) having a high pressure area (9) in a high pressure chamber (5) and a low pressure area (8) in a low pressure chamber (3), and a switching valve (11) having a pressured control valve element having a larger pressure area (16) and a small pressure area (17). Such a pressure amplifier should have a high operating frequency. To this end the valve element (10) and the amplification piston (5) are located in a same bore (3, 4) in the housing (2).

A hydraulic pressure intensifier (1) is described comprising a housing (2) having a low pressure chamber (3) and a high pressure chamber (4), force transmitting means (5) between the low pressure chamber (3) and the high pressure chamber (4), and a switching valve (8) connecting the low pressure chamber (3) to a first pressure or to a second pressure different from the first pressure. It is intended to have a large volume on the high pressure side of the pressure intensifier. To this end the switching valve (8) is controlled by a pilot valve 18.

A double acting hydraulic pressure intensifier (1) is described comprising a housing (2), a first piston arrangement (7) having a first high pressure piston (8) in a first high pressure chamber (3) in the housing (2) and a first low pressure piston (9) in a first low pressure chamber (5) of the housing (2), a second piston arrangement (10), having a second high pressure piston (11) in a second high pressure chamber (4) in the housing (2) and a second low pressure piston (12) in a second low pressure chamber (6) in the housing (2), and a switching valve (14) having a valve element (15). Such a pressure intensifier should be made compact. To this end the switching valve (14) is located between the first piston arrangement (7) and the second piston arrangement (10).

A fluid pump may include a fluid chamber, a plunger configured to reciprocate within the fluid chamber, and a valve system including multiple valves. The multiple valves each may be configured to control fluid flow into the fluid chamber or each may be configured to control fluid flow out from the fluid chamber.

A valve system is disclosed for controlling fluid flow into or out of a fluid chamber of a fluid end of a hydraulic fracturing pump, the fluid flow to be caused by a reciprocating plunger that is driven by a power end of the hydraulic fracturing pump. The valve system may include a valve seat defining multiple bores in parallel and multiple valves configured to sealingly engage the valve seat at respective bores of the multiple bores.