A cartridge hand pump is disclosed. The cartridge hand pump comprises a housing; a lever extending from the housing; a cylinder provided in the housing wherein the cylinder is connected to a supply passage for receiving hydraulic fluid and to an actuator passage for sending pressurised hydraulic fluid; and a piston slidably positioned in the cylinder, the piston being operably connected to the lever for movement between a first position and a second position wherein the movement of the piston from the first to the second position sends pressurised fluid to the actuator passage characterised by a pressure relief valve accommodated in the housing wherein the pressure relief valve is in communication with the actuator passage such that pressurised hydraulic fluid is discharged through the pressure relief valve when pressure in the actuator passage exceeds a predetermined value.

A real-time monitoring system for skid-mounted reciprocating natural gas compressors. The system not only monitors performance and makes analytical diagnostic predictions of potentially problematic valves and such, but also has alert system for real-time monitoring, troubleshooting and diagnosing of such natural gas compressors—both locally and remotely. Operators can more efficiently and effectively manage maintenance and operation of the skid-mounted compressors with the implementation of LED equipped sensors that allow operators to locally quickly identify valves and other components requiring maintenance. Additionally, operators can remotely identify and understand deviations from optimal performance with the implementation of color-coded soft gauges.

Provided is a cooling device capable of surely stopping the operation of a compressor when stopping the operation of the compressor is required. A cooling device comprises: a motor for driving a compressor that constitutes a refrigerant circuit for cooling a cooling room (R); and a first relay and a second relay that are arranged in series on an electric circuit for supplying electric power to the motor.

Aspects are provided for positive displacement pumps and methods and systems for controlling such pumps for dispensing at a flow rate based on a downstream flow sensor. A pump controller determines a targeted motor speed for a flow rate set point based on a flow rate function. The pump controller determines a predicted movement time for a motor of the pump to change from a current motor speed to the targeted motor speed, a predicted wait time to reach a flow rate corresponding to the targeted motor speed, and a measurement time after the wait time. The pump controller controls the positive displacement pump according to consecutive control cycles, each control cycle includes a pump movement sub-cycle, a wait sub-cycle, and a measurement sub-cycle. The pump controller determines a measured flow rate during the measurement sub-cycle. A subsequent control cycle is based on the measured flow rate.

Aspects are provided for positive displacement pumps and methods and systems for controlling such positive displacement pumps for accurate volume dispensing. The pump may run a calibration procedure to determine a mapping between a pump speed and a flow rate for a current configuration of the positive displacement pump, a tubing size, and a fluid characteristic. A pump controller may determine a pump motion profile based on the mapping. The pump motion profile includes an acceleration phase, a constant speed phase, and a deceleration phase such that a total volume pumped according to the pump motion profile and the mapping is equal to a target volume. The pump controller may determine an adjustment to the pump motion profile based on a constant flow rate measured during operation. The pump controller may decelerate the positive displacement pump according to the adjusted pump motion profile until the target volume is dispensed.

Systems and methods to pump fracturing fluid into a wellhead may include a gas turbine engine including a compressor turbine shaft connected to a compressor, and a power turbine output shaft connected to a power turbine. The compressor turbine shaft and the power turbine output shaft may be rotatable at different rotational speeds. The systems may also include a transmission including a transmission input shaft connected to the power turbine output shaft and a transmission output shaft connected to a hydraulic fracturing pump. The systems may also include a fracturing unit controller configured to control one or more of the rotational speeds of the compressor turbine shaft, the power turbine output shaft, or the transmission output shaft based at least in part on target signals and fluid flow signals indicative of one or more of pressure or flow rate associated with fracturing fluid pumped into the wellhead.

An oscillation controller operates on engine speed or RPM data from a pump or pumping unit associated with a wellbore operation. The oscillation controller determines a measure of variability, such as a bandwidth, for the engine speed over a rolling time window and compares the measure of variability to an oscillation bandwidth threshold. The oscillation controller determines that erratic behavior or oscillation is present when the measure of variability exceeds the oscillation bandwidth threshold, and for such instances measures a duration of erratic behavior with a variability timer. If the oscillation controller determines that the erratic behavior has subsided, the variability timer is cleared. The oscillation controller generates at least one warning whenever the variability timer exceeds an oscillation warning threshold. The oscillation controller mitigates erratic behavior by downshifting (or shifting to neutral) at least one gear of the pump or pumping unit if the variability timer exceeds an oscillation mitigation time threshold.

A fluid control device includes a piezoelectric pump having a piezoelectric element, a driving circuit that receives a driving power supply voltage applied thereto and drives the piezoelectric element, and a startup circuit disposed between the driving circuit and an input terminal for a power supply voltage. The startup circuit increases the driving power supply voltage to a voltage (V1) lower than a constant voltage (Vc) in a first stage (P1) after startup, maintains or decreases the driving power supply voltage in a second stage (P2) following the first stage (P1), and increases the driving power supply voltage to the constant voltage (Vc) in a third stage (P3) following the second stage (P2).

A fluid control device includes a piezoelectric pump having a piezoelectric element, a driving circuit that receives a driving power supply voltage applied thereto and drives the piezoelectric element, and a startup circuit disposed between the driving circuit and an input terminal for a power supply voltage. The startup circuit increases the driving power supply voltage to a voltage (V1) lower than a constant voltage (Vc) in a first stage (P1) after startup, maintains or decreases the driving power supply voltage in a second stage (P2) following the first stage (P1), and increases the driving power supply voltage to the constant voltage (Vc) in a third stage (P3) following the second stage (P2).

Provided is a pump apparatus capable of suppressing an unintentional ejection of a high-pressure liquid from a nozzle. A pump apparatus including: an injection chamber having a door; a nozzle arranged in the injection chamber; a pump connected to the nozzle for discharging liquid; a motor for driving the pump; a door sensor for detecting that the door is closed; and a control device capable of communicating with the door sensor, the control device having a motor rotation unit for supplying driving power to the motor only when the door sensor detects that the door is closed.