Automatic Vacuum Controller with Solenoid Valve

What is the Automatic Vacuum Controller with Solenoid Valve?

An automatic vacuum controller with a solenoid valve holds a set vacuum without operator intervention, switching a bleed valve to maintain pressure. It is used for long, unattended evaporation and drying processes.

Overview

This controller packages the pressure sensor, control electronics and a solenoid bleed valve in one unit. The solenoid opens and closes to admit small amounts of air, raising pressure when the pump pulls it too low. Control is on-off with adjustable hysteresis, so the valve does not chatter, and the setpoint is entered digitally. Some units include a second valve for venting at the end of a run, and a relay for the pump. Because it is self-contained, the controller handles the full regulation loop and can run for hours unattended. It maintains pressure within a band of a few millibars, which suits rotary evaporation, vacuum concentration, drying and distillation. Wetted parts are PTFE or stainless steel, and connections are KF flanges or hose barbs. The unit may be bench-top or mounted on the pump or a stand.

How does it work?

A vacuum controller combines a pressure sensor, a control algorithm and an output that acts on the vacuum system. The sensor, usually a piezoresistive or capacitive absolute pressure transducer, measures pressure from atmospheric down to a few millibars. The controller compares this value with the setpoint and adjusts either the pump speed or, more often, a solenoid or proportional valve that bleeds air into the line. A PID or on-off algorithm holds the pressure within a band, and the display shows the current and target values. Some controllers add ramps so that pressure changes gradually, and inputs for a solvent library or an external sensor at the sample. Outputs may include relay contacts for the pump, an analog or digital signal, and alarm contacts for out-of-range conditions.

What are the key features?

• Integrated sensor, controller and solenoid bleed valve
• On-off control with adjustable hysteresis
• Vent valve option for end-of-run release
• Relay for pump switching
• Pressure held within a few mbar band
• Suited to unattended operation for hours

What are the technical specifications?

A typical automatic vacuum controller with solenoid valve configuration offers pressure range of 1,000–1 mbar, control type of Automatic on-off, hysteresis of Adjustable, 1–100 mbar, valve of Solenoid, PTFE body, vent valve of Optional, automatic and pump relay of 250 V AC 3 A. Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The Automatic Vacuum Controller with Solenoid Valve is used in unattended rotary evaporation, vacuum concentration, automated drying cycles, distillation with fixed pressure and overnight sample preparation. Across the wider Vacuum Controllers class, laboratories also deploy it for rotary evaporation control, vacuum distillation and solvent recovery and vacuum filtration and degassing.

Which standards and certifications apply?

Relevant standards and methods include IEC 61010-1, IEC 61326-1, ISO 21360, ISO 9001 and GB 4793.1. Certification candidates for this model are CE, RoHS and ISO 9001 manufacturing; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Calibrate or verify the pressure sensor periodically against a reference gauge, because drift changes the boiling point and therefore the process. Keep the bleed valve and sensor port clean and dry, since condensate or particles cause erratic readings. Fit a cold trap or separator between the controller and the pumped vapor to protect both, and mount the controller above the liquid level. Use ramps to avoid bumping and foaming when pressure is reduced quickly. Follow IEC 61010-1 for electrical safety and check that the valve materials suit the solvents in use. Record setpoints and ramp programs in the method so that runs are reproducible, and log pressure data where the process is regulated.

How do I select the right Automatic Vacuum Controller with Solenoid Valve?

Choose this controller when the process runs unattended and the setpoint must be held automatically. For gradual pressure changes, choose a ramp-capable model. In the RFQ, state pressure range, valve materials, vent needs and pump switching.

How does it compare with other Vacuum Controllers variants?

Match the control range to your process: rotary evaporation and distillation usually need control from atmospheric down to about 10 mbar, while filtration and coating may need lower. Check the measurement accuracy and resolution, since fine control of boiling depends on both. Decide whether you need on-off control with a solenoid valve or proportional control, which is smoother but more expensive. Confirm the valve is compatible with the vapors being pumped and that its orifice suits your pump flow. Consider whether ramps, solvent libraries and an external sample sensor are useful for your methods, and whether the controller can drive your pump directly or only a bleed valve. Check the interface, alarm contacts and whether a separate gauge is still needed.