Helpful Graphs
Solenoid Valve Temperature Profile
Solenoid Valve Time On-Off Profile
Orifice sizes of Modulating & Solenoid Valves
Simplified Process Flow Circuit
Comparison of Modulating and Solenoid Valves in the Cooling Phase
AVT™
The orifice rotates constantly, making minute adjustments.
Solenoid
The valve is mechanically full open or full closed in sudden pulses.
AVT™
The AVT™ is consistently 'partially' open, it rejects heat (BTU) in greater capacity than a solenoid valve of the same 'pipe size'.
Solenoid
A solenoid controls temperature by being pulsed on and off over time (i.e. on for 2 seconds, off for 10 seconds). It's typically off more than on.
AVT™
The AVT™ is less susceptible to plugging or fouling because particles entering the valve can pass straight through. The AVT™ valve actually cleans itself as the ball rotates.
Solenoid
Solenoid valves are susceptible to fouling because particles must navigate a serpentine course through the valve body. The small diaphragm pilot hole is readily fouled.
AVT™
Variations in water supply pressure or temperature (or both) are compensated for by the simple reposition on the orifice ball.
Solenoid
With solenoid valves, the only compensation possible is to increase or decrease the amount of time ‘on’ and time ‘off’. The greater the pulsation results in increased mechanical wear and also increases the impact of water hammer and temperature fluctuations.
AVT™
Temperature control is a straight line with no cycling.
Solenoid
Batch introduction of cooling water causes the system to cool below the set point. In the absence of a wide dead band, the heater is activated to compensate for the batch cooling. This sets up a condition know as 'cycling', where considerable mechanical and electrical waste occurs.
AVT™
There is no water hammer concussion to create spike pressures which are the leading cause of pump seal failures.
Solenoid
Each cooling pulse creates a sharp pressure spike which compresses the pump seal faces increasing frictional and abrasive wear.
