Methods can comprise charging a first hydraulic device of a first hydraulic circuit with a first quantity of hydraulic fluid from a hydraulic fluid source. The methods can further comprise pressurizing a control segment and locking the first quantity of hydraulic fluid from exiting the first hydraulic circuit in response to hydraulic pressure within the control segment. The methods can also include unlocking the first quantity of hydraulic fluid to permit exiting of the first quantity of hydraulic fluid from the first hydraulic device in response to dropping the hydraulic pressure within the control segment after a delay. Hydraulic apparatus can comprise a normally open hydraulic pilot operated control valve that can be configured to hydraulically lock a first hydraulic device in response to a hydraulic pressure within a control segment rising to greater than or equal to an actuation pressure.

A pig pumping unit is provided that allows eight passes to be made simultaneously with a single pumping unit. A single engine is used to drive three or four pumps, each connected into separate pumping units. Two engines may thus be used to drive up to eight pumps in a single trailer.

A pig pumping unit is provided that allows eight passes to be made simultaneously with a single pumping unit. A single engine is used to drive three or four pumps, each connected into separate pumping units. Two engines may thus be used to drive up to eight pumps in a single trailer.

A fluid valve has a valve plug configured as follows. In order to control a flow rate of a fluid between a first pressure chamber and a second pressure chamber, the valve plug is provided so as to be openable and closable in accordance with a difference between forces generated by pressures in the pressure chambers and resilience of an elastic member. The fluid valve includes an opening motion promoting portion. The opening motion promoting portion promotes an increase in degree of opening of the valve plug after the valve plug has been opened.

A fluid valve has a valve plug configured as follows. In order to control a flow rate of a fluid between a first pressure chamber and a second pressure chamber, the valve plug is provided so as to be openable and closable in accordance with a difference between forces generated by pressures in the pressure chambers and resilience of an elastic member. The fluid valve includes an opening motion promoting portion. The opening motion promoting portion promotes an increase in degree of opening of the valve plug after the valve plug has been opened.

A control assembly that is configured to operate large, heavy duty flow controls. The control assembly may include a main support and a thin plate disposed on the main support, the thin plate having four sides forming a mounting surface, the thin plate also having lateral slots that extend lengthwise in a first direction between two of the sides and are arranged so adjacent lateral slots are spaced apart from one another in a second direction perpendicular to the first direction.

A control assembly that is configured to operate large, heavy duty flow controls. The control assembly may include a main support and a thin plate disposed on the main support, the thin plate having four sides forming a mounting surface, the thin plate also having lateral slots that extend lengthwise in a first direction between two of the sides and are arranged so adjacent lateral slots are spaced apart from one another in a second direction perpendicular to the first direction.

Provided is a switching valve for use in an analyzer module for switching flow passages of fluids, in which the manufacturing cost is reduced and the life is increased. The valve element is provided with a lower contact portion that comes into close contact with a lower valve seat disposed at a valve body when a valve is closed, and with an upper contact portion that comes into close contact with an upper valve seat disposed at a counter plate when the valve is open. The counter plate has a first recess that is open downward and a second recess that is open toward the first recess and has a smaller horizontal cross-sectional area than that of the first recess, and the upper valve seat is press-fitted into the second recess.

Provided is a switching valve for use in an analyzer module for switching flow passages of fluids, in which the manufacturing cost is reduced and the life is increased. The valve element is provided with a lower contact portion that comes into close contact with a lower valve seat disposed at a valve body when a valve is closed, and with an upper contact portion that comes into close contact with an upper valve seat disposed at a counter plate when the valve is open. The counter plate has a first recess that is open downward and a second recess that is open toward the first recess and has a smaller horizontal cross-sectional area than that of the first recess, and the upper valve seat is press-fitted into the second recess.

A cylinder assembly comprising at least one tubular section with an open end and an opposite end closed by a cylinder head, the tubular section comprising a tubular member, the cylinder assembly further comprising a shaver secured to an inner wall of the cylinder head; and the shaver having an edge having a round profile, with a curvature radius comprised in a range between 0.0002 and 0.002, an inner diameter equal to an outer diameter of the tubular member and a surface hardness at least equal to a hardness of the surface of the tubular member.