Solenoid pumps controllers

In the MiniMed implantable pump, a piston pump drives insulin through the delivery catheter. A patented solenoid motor controls the piston movement, to aspirate insulin from the reservoir chamber into the piston chamber and then push it through the insulin delivery catheter. 

The metering b.in has a capacity of 1.6 m3 and has a live bottom discharge. A hydraulic motor drives the drag chain conveyor. A hydraulic power unit equipped with an electrically driven pump, flow regulator valve, pressure relief valve, and solenoid valve control the flow and pressure of hydraulic fluid... 

The Varian Model 8500 pump (Fig. 5) is the most sophisticated syringe-type pump. There are two gas solenoid valves, the first of which pressurizes the solvent container to re-fill the chamber and the second actuates a pneumatic valve downstream of the pressure transducer on the column tubing. The operating controls are selected automatically by depressing push-button switches on the front panel of the pump controller. These switches control the opening of the... 

The solenoid valve array with necessary relay circuits and the controller are integrated together to produce a single stand-alone pneumatic pump controller unit. For the compressed air supply, a separate pressure tank or air compressor is needed. A pressure regulator with air filter is located between the air supply and the vale manifold. 

Keywords— Air pressure monitoring, air pump/motor control, solenoid valve control, low power portable medical equipment. 

Titrations may be automated using a pump to deliver the titrant at a constant flow rate, and a solenoid valve to control the flow (Figure 9.5). The volume of titrant delivered is determined by multiplying the flow rate by the elapsed time. Automated titrations offer the additional advantage of using a microcomputer for data storage and analysis. 

A low-pressure switch can also be used in conjunction with a thermostat and a solenoid valve in the pump-down circuit. In this method of control, the thermostat does not stop the compressor but de-energizes the liquid line solenoid valve to stop the supply of refrigerant to the evaporator. The compressor continues to run and pumps down the evaporator until stopped by the low-pressure switch. When the thermostat again calls for cooling, it opens the solenoid valve, liquid enters the evaporator and the low-pressure switch will close again to restart the compressor. This method is used to ensure that the evaporator is kept clear of liquid when the plant is off. If there is any leak at the solenoid valve, it will cause the... 

Solenoid valves are used in refrigeration and air-conditioning systems for refrigerant lines, oil pressure pipes (to control oil return and capacity reducers), and water and compressed air lines. Four-port changeover valves (Figure 9Ab) are used to reverse flow in defrosting and heat pump circuits. A de-energized expansion valve will act as a solenoid valve. 

Four different types of tasks are performed by automation. Two involve the sequencing of valves and pumps Involved 1n the setup and completion of the designed experiment through the operation of the test and hydraulic fluid systems. The other tasks involve the control of the temperature bath and data collection. To perform these tasks, a1r-actuated solenoids and optically coupled sol Id-state relays are used. These devices are controlled by an electrical circuit consisting of the device connected 1n series with a power supply and a channel on the actuator card In the HP 3497. The power supply 1s either 24 VDC for use with the solenoids or 5 VDC for the solid-state relays. The actuator output channel acts as a simple on/off switch which allows power to be supplied to the solenoid or relay when closed. The logic of the circuit 1s controlled by application programs running on the local HP 1000. 

Reciprocating positive displacement pumps may have adjustment of the length or frequency of the stroke as another control feature. These may be solenoid or pneumatic devices that can be operated off a flow controller, as shown on Figure 3.21(d). 

A system controller sends out pump speed control signals to set flow rates and to generate solvent gradients. It should also be able to send 0- to 5-mV contact closure signals to actuate external switches and equipment. It also may be able to send out a 0- to 30-V powered contact closure signal needed to run solenoid valves used to control air pressure and liquid flows. Finally, the... 

Electrophoresis can also be conducted on-line, as an element of industrial process monitoring and/or control. In this case a slip-stream sample is usually withdrawn from a process vessel, diluted in a mixing tank to reduce the sample turbidity, and then pumped through an electrophoresis cell that is fitted with stop-flow solenoid valves. The flow is stopped for long enough to make an electrophoresis measurement and then resumed. The sampling can be either intermittent or continuous. An example is described in reference [265]). 

The reaction of l-hexene on 1/16 1 Pt/ AlaOj (Engelhard E-302) reforming catalyst extrudates was chosen as the test reaction. Figure 1 shows a schematic of the reactor unit A Waters dual piston HPLC pump rated to provide flow rates between 6 and 600 ml/h with a pressure head up to 414 bar was used to feed 1-hexene (Ethyl Corporation CAS 592-41-6 Lot 851201). By closing the liquid shut-off valve (V3) and opening the gas shut-off valve (V2), either hydrogen or nitrogen gas may be admitted to the reactor unit. The feed gas was selected by a three-way, computer-controlled solenoid valve (VI). 

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