The Pro's and Cons of a Motor Actuated ball valve and a Solenoid Valve

Why use a solenoid valve?

Positives:

+++ Solenoid valves offer fast, reliable on/ off control for most clean gases and fluids under 50 centistokes, with life expectancy exceeding 1 million cycles.

+++Solenoid valves are typically much less expensive than motor actuated valves, however the Connexion ABVM + ABV units now provide a very cost-effective and reliable option.

+++ Solenoid valves are typically normally closed (failsafe closed) by design, the option for a normally open (failsafe open) function can be achieved in some instances by simply changing the armature assembly.

+++Solenoid valves can be repaired by replacing either seals or replacing the solenoid coil with same or different voltage.

Negatives

--- Media must be clean and free from contaminants and debris to avoid failure to seal.

---Solenoid valves typically control flow in one direction (uni-directional) inlet to outlet only, except for coaxial valves

---Solenoid valves require power to stay in position, typically 5 to 20 Watts up to 100+ watts for large zero-rated solenoid valves. 

Except Latching solenoid valves that require a short electrical power pulse to stay open, <> a reverse polarity electrical power pulse will stay closed. (Swap +ve/-ve to -ve/+ve)

---Solenoid valves are typically fast acting 10-100 msec, which will cause water hammer with fast moving water.

However, the PU220D series WRAS approved solenoid valve is designed to close more slowly 250-500mSec to reduce water hammer. A water hammer arrestor can be installed.

---Choosing the right solenoid valve according to pressure, flow and media can be confusing. Different solenoid valves require either a minimum pressure difference between inlet and outlet and are affected by back pressures from downstream systems, valves or spray nozzles.

. 2/2 way normally closed assisted lift diaphragm (Typically 0 to 10 Bar)	; 2/2 way normally closed pressure assisted diaphragm (Typically 0.5 to 10 Bar)
2/2 way normally closed direct acting (Typically 0 to 10 Bar)	3/2 way normally closed direct acting (Typically 0 to 10 Bar)

---Solenoid valve coils get hot when energised and can exceed +100C after 20 minutes.

---Solenoid valves used for hard water can suffer from limescale build up if the coil in energised and remains hot for long periods of time. This prevents the valve from operating correctly.

---Solenoid valves are an electro mechanical device that generates a magnetic field to move an internal plunger, this can attract any metal and rust particles typically found in most non-filtered mains water systems.

---The flow path through a solenoid valve requires several changes in direction that will reduce flow.

---Position feed back for a solenoid valve is an expensive additional cost.

---Manual override facility for a solenoid valve can be an expensive option. Unless you use a solenoid commissioning magnet.

Why use a motor actuated ball valve?

Positives.

+++Motor actuated valves offer reliable on/off control for most fluids and gases, even contaminated and think glutinous media up to 500 centistokes.

+++Electric actuators only require power to move and do not produce heat to stay in position, so are ideal for hard water areas to avoid limescale.

+++Power open / power close will stay put when power is removed.

Failsafe return back to the start position when electrical power is removed.

+++The Connexion ABVM motor ball valve only requires 5 Watts to move and under 1 Watt to maintain powered position.

+++Electric actuators do not produce sufficient magnetic field to attract rust or metal debris from mains water systems.

+++Motor actuated valves are unlikely to produce water hammer caused by fast moving liquid media when either opening or closing due to the 5 to 20 second open or close time.

+++Full flow ball valves typically offer full unimpeded bidirectional flow in either direction with minimal drop in pressure and flow.

+++Motor actuators are typically supplied with manual override and position feed back switches or as an option with minimal extra cost.

 

Negatives.

---Motor actuated ball valves are slower to react and can require 5 to 20 seconds to fully open or close.

---Motor actuated ball valves are typically more expensive, bigger and heavier than solenoid valves up to about 2 inch port. However, the Connexion ABVM and ABV actuator units are very cost-effective and extremely compact.

--- Motor actuators are typically limited to 1 cycle every 2 to 5 minutes, with a cycle life expectancy up to 20,000+ cycles.

The Connexion ABVM and ABV units can cycle every 30 seconds, with a cycle life exceeding 70,000 cycles.

---Electric actuators typically cannot be repaired and need to be replaced, unless with ISO9211 mount where the head unit can be replaced without removing or isolating the valve body.

Conclusion:

If you need fast on off control for regular short periods of time for clean fluid or gas media, have a guaranteed pressure difference between inlet and outlet, use a solenoid valve.

If the valve is to be powered on for long periods of time to control dirty or contaminated media; hard unfiltered water; with or without a pressure difference or could have flow in either direction, use a motor actuated ball valve.