Dry-operated solenoid valves
Original article date: July 1999
Alan Quinn takes a look at the KV Automation range of dry-operated solenoid valves in which the solenoid is isolated from the valve body and media.
To enable solenoid valves to control the flow of aggressive or contaminating media KV Automation is offering a dry operator version as part of its FAS range. It is an available option for the miniature Microsol valves for the larger more powerful Minisol units and also for the largest of all the valves in the FAS range the Bacosol.
A feature of the dry operator design is that it provides complete isolation for the solenoid mechanism from the body of the valve and from the media which flows through it.
On being energised the solenoid armature will move up and down depending on electrical configuration thereby opening and closing the diaphragm of the valve. The diaphragm’s seal separates the media from the operating mechanism of the solenoid preventing contamination of the valve interior components. For compatibility with different media the seal is available in a variety of materials.
In addition to a range of diaphragm seal materials the valve body also comes in various material options including a number of plastics compatible with gaseous or liquid media.
Microsol valves which have gas and water monitoring applications van be supplied with different orifice sizes from 0.5 to 2.0mm diameter to suit flow requirements – 8bar is the highest permitted pressure. Solenoid power requirements can be as low as 1W and the valves can be operated using AC or DC over the range 6 to 240V. Options for these valves include LED surge suppression and latching styles. The valves are manufactured in 2 3 and 5/2 way versions.
The next size up the Minisol in 2/2 and 3/2 way porting with NC and NO operation comes either body ported as an independently operated valve or ready for sub-base mounting. It has orifice sizes from 1.2 to 4mm. Media pressure can go up to 7bar. Electrical power consumption is 5W across the same voltage range as the Microsol.
A feature of this valve when the valve has a three-port configuration is the internal rocker mechanism which opens and closes any two ports of three. In effect this three-port operator allows aggressive gases for example to be switched one way or the other through the valve. It is a useful asset especially when sampling is being carried out or when as purging operation is needed as well as for gas diverting or mixing functions.
At the upper end of the FAS range is the Bacosol family. These are the largest. Most powerful valves in the range with ports up to 3/8BSP. Orifice sizes go up to 11mm. The same diaphragm seal and body material options exist to allow for use for use with chemically aggressive gases and liquids but for use where higher flow rates are required.
| Picosol – the ultra-miniature solenoid valve
An ultra-miniature version of the Microsol valve is the 10mm Picosol valve. It has a 0.8mm orifice and will handle up to 7bar pressure. As with the miniature 15mm Microsol it can be operated using armature latching to provide an exceptionally low power consumption. With this system power is applied to the solenoid in 10ms pulses. Once the valve has been pulsed the electrical signal can be removed from the valve with the valve remaining in the latched position with zero power consumption. This low power utilisation makes the valves eminently suitable for use with battery-powered equipment. It is estimated that a five year life is possible from a single small battery when employing the valve’s latching pulse system. Both the Microsol and Picosol can be operated independently in a pneumatic circuit or as a pilot for larger-sized valves. All connections are contained within the body of the valves thus permitting the use of common pressure and exhaust via the sub-base. Integrated options include LED on/off indication an intrinsically safe electronic circuit which provides a new approach to the conventional explosion-protected enclosure and surge suppression to avoid transmitting voltage spikes. There’s also a choice of electrical connections including AMP spade terminals flying leads and – for the Picosol – a snap-in connector option. The Picosol valves are manufactured in 2/2 and 3/2 way versions whilst Microsol comes additionally with a 5/2 configuration. They can all be energised either normally closed or normally open. Both families of valves work with AC or DC supply off a range of voltages from 6 to 240V. |
- KV Automation Systems
- David Hynd
- 01908 561515
July 1999