A gas compressor includes inverters, a plurality of compressor units and a control device for controlling each of the inverters. The control device increases the number of compressor bodies to be operated after confirming that the rotational speed of the operational motors will reach a steady value immediately after causing the number of the compressor bodies to be operated to increase.

A gas compressor includes inverters, a plurality of compressor units and a control device for controlling each of the inverters. The control device increases the number of compressor bodies to be operated after confirming that the rotational speed of the operational motors will reach a steady value immediately after causing the number of the compressor bodies to be operated to increase.

The present disclosure relates generally to well operations. The present disclosure relates more particularly to a systems and methods for independently and/or simultaneously treating multiple wells from a centralized location using a split flow pumping system configuration. The split flow pumping system configuration may comprise one or more blenders, one or more boost pumps, a pumping system comprising one or more pumps, a component storage system, and a fluid storage system for treatment of two or more wells using two or more treatment compositions. The split flow pumping system configuration may comprise one or more controllers for controlling the one or more blenders, the one or more boost pumps, the pumping system comprising one or more pumps, the component storage system, and the fluid storage system. The system may comprise one or more sensors for collecting data corresponding to the one or more pressures, flow rates, injection rates, compositions, temperatures, and densities of at least one of the first composition and the second composition, wherein the controller controls the one or more pressures, flow rates, injection rates, compositions, temperatures, and densities of at least one of the first composition and the second composition based, at least in part, on the data.

Pumps for noncontact tonometry are provided. In one embodiment, a pump for noncontact tonometry includes a compression pump, a compression chamber, a first pressure sensor in communication with the compression chamber, a surge chamber, and a valve separating the compression chamber and surge chamber. The compression pump compresses a first volume of gas into the compression chamber. When the first pressure sensor detects a threshold pressure in the compression chamber, the valve opens and releases the gas into a surge chamber, where it combines with a gas residing in the surge chamber to form a puff of gas that escapes from the surge chamber through a flow-limiting nozzle. The components of the pump, which relies on passive rather than active components to create the controlled puff, can be assembled to have a profile that is portable and fit for home use.

Pumps for noncontact tonometry are provided. In one embodiment, a pump for noncontact tonometry includes a compression pump, a compression chamber, a first pressure sensor in communication with the compression chamber, a surge chamber, and a valve separating the compression chamber and surge chamber. The compression pump compresses a first volume of gas into the compression chamber. When the first pressure sensor detects a threshold pressure in the compression chamber, the valve opens and releases the gas into a surge chamber, where it combines with a gas residing in the surge chamber to form a puff of gas that escapes from the surge chamber through a flow-limiting nozzle. The components of the pump, which relies on passive rather than active components to create the controlled puff, can be assembled to have a profile that is portable and fit for home use.

A surge suppressor includes a boost mechanism configured to balance pressures between a working fluid and a process fluid. The boost mechanism includes a boost member that is acted on by a charge pressure of the working fluid. A shaft extends from the boost member to a pressure control member bounding the process fluid and acting on the process fluid. The boost member can have a larger effective area than the pressure control member to provide a pressure multiplication between the charge pressure and the process fluid pressure. In addition, pressure control valves are mounted to an air housing and actuated open by the boost mechanism. Actuating one of the pressure control valves open increases the charge pressure. Actuating the other pressure control valve open decreases the charge pressure.

A surge suppressor includes a boost mechanism configured to balance pressures between a working fluid and a process fluid. The boost mechanism includes a boost member that is acted on by a charge pressure of the working fluid. A shaft extends from the boost member to a pressure control member bounding the process fluid and acting on the process fluid. The boost member can have a larger effective area than the pressure control member to provide a pressure multiplication between the charge pressure and the process fluid pressure. In addition, pressure control valves are mounted to an air housing and actuated open by the boost mechanism. Actuating one of the pressure control valves open increases the charge pressure. Actuating the other pressure control valve open decreases the charge pressure.

A pump control assembly for controlling a variable displacement hydraulic pump includes a spool mounted within a valve block. The spool is configured to move between a first and a second position within the valve block so as to selectively control the displacement of the attached pump. The pump control assembly further includes first and second chambers that each apply a force to opposite ends of the spool. The first chamber is positioned at a first end of the spool in fluid communication with a pump output port. The second chamber is positioned at a second end of the spool and in fluid communication with a hydraulic tank port and a proportional pressure reducing valve. The second chamber also includes a piston and first and second springs positioned on either side of the piston. The proportional pressure reducing valve provides a regulated pressure to a first side of the piston along with the first spring, and the hydraulic tank port provides a tank pressure on the opposite side of the piston along with the second spring. The pump control assembly also includes a stop structure having a positive stop that limits movement of the piston in a direction toward the first chamber.

A pump control assembly for controlling a variable displacement hydraulic pump includes a spool mounted within a valve block. The spool is configured to move between a first and a second position within the valve block so as to selectively control the displacement of the attached pump. The pump control assembly further includes first and second chambers that each apply a force to opposite ends of the spool. The first chamber is positioned at a first end of the spool in fluid communication with a pump output port. The second chamber is positioned at a second end of the spool and in fluid communication with a hydraulic tank port and a proportional pressure reducing valve. The second chamber also includes a piston and first and second springs positioned on either side of the piston. The proportional pressure reducing valve provides a regulated pressure to a first side of the piston along with the first spring, and the hydraulic tank port provides a tank pressure on the opposite side of the piston along with the second spring. The pump control assembly also includes a stop structure having a positive stop that limits movement of the piston in a direction toward the first chamber.

A variable frequency drive system and a method of controlling a pump driven by a motor with the pump in fluid communication with a fluid system is provided. The method includes monitoring a pressure in the fluid system, monitoring and adjusting an operating frequency of the motor to maintain the pressure at a pressure set point, and, based on the monitored operating frequency, causing the pump to temporarily boost the pressure in the fluid system to a temporary boost set point for a first time period. The method also includes determining whether the temporarily boosted pressure in the fluid system stays above the pressure set point for a second time period and causing the pump to enter a sleep mode when the temporarily boosted pressure stays above the pressure set point through the second time period.