Anti Water Hammer Arrestor – Z-Tide AIT / APT Series
The Z-Tide Industrial AIT and APT Series are diaphragm-type anti water hammer arrestors designed to absorb hydraulic pressure surges and protect pumps, valves, pipework and equipment from damaging water hammer.
Both ranges use a sealed NBR diaphragm air chamber to cushion sudden pressure increases caused by fast-closing valves, pump operation and rapid changes in water velocity. The diaphragm separates the air cushion from the water, providing consistent surge absorption without direct air contact with the pipeline medium.
Two complementary designs are available: the AIT Series provides the widest choice of sizes and body materials for general industrial applications, while the
APT Series is a compact stainless steel CF8 big-chamber water hammer arrestor for ½" to 1" threaded installations.
AIT & APT Series Options
Rather than treating the two models as identical, I would give customers a simple choice between two related designs.
AIT Series – I-Style Water Hammer Arrestor
The AIT is the broader industrial range, available in threaded sizes from:
½"
¾"
1"
1¼"
1½"
2"
2½"
3"
4"
APT Series – Big Chamber Arrestor
The APT is described by Z-Tide as its Big Chamber Water Hammer Arrester and is available in:
½"
¾"
1"
Body:
Stainless steel CF8
The larger chamber relative to its connection size provides a compact surge-control solution for smaller threaded water systems.
Function & Operation
Function:
Anti water hammer surge arrestor
Hydraulic pressure shock absorber
Operating principle:
Diaphragm-separated air cushion
When a valve closes rapidly or water velocity changes suddenly, the resulting pressure wave enters the arrestor.
The diaphragm compresses the trapped air cushion, absorbing part of the hydraulic energy rather than allowing the full pressure spike to propagate through the pipe system.
As the transient pressure subsides, the compressed air expands and returns the diaphragm towards its normal position.
AIT Pressure & Temperature
AIT applied medium: Water
Temperature: -15°C to +80°C
Cast iron: 21 kgf/cm²
Bronze: 21 kgf/cm²
Ductile iron: 32 kgf/cm²
Stainless steel: 32 kgf/cm²
APT Pressure & Temperature
The APT has a different operating specification:
Working pressure: 10 kgf/cm²
Body test pressure: 16 kgf/cm²
Temperature: 0°C to +60°C
Medium:
Water
Diaphragm: NBR
Installation: Horizontal or vertical
Construction & Materials
AIT Series
The supplied AIT sheet shows multiple body-material versions, including stainless steel and bronze, with the applicable body pressure test dependent upon material.
Diaphragm: NBR
APT Series
Body: Stainless steel CF8
Diaphragm: NBR
Air Charging Connection
Both designs incorporate an air charging point at the top of the chamber.
This allows the air side of the diaphragm chamber to be charged appropriately for the installation.
Pressure Gauges
The threaded AIT and APT versions are supplied without a pressure gauge.
The larger flanged AIF version shown alongside the AIT is illustrated with a gauge, but that shouldn't be carried across to the threaded AIT/APT specification.
Installation
Both AIT and APT versions may be installed: Vertically or Horizontally
This gives considerable flexibility when positioning the arrestor close to the source of hydraulic shock.
Typical Applications
Fast-closing solenoid valves
Motorised control valves
Pump discharge systems
Booster pump installations
Industrial water systems
Commercial water services
Cooling water systems
Process water systems
Municipal water installations
General pipeline surge protection
These arrestors are particularly useful close to fast-closing solenoid valves, where rapid interruption of water velocity can generate a substantial transient pressure spike.
AIT or APT – Which Should I Choose?
Choose AIT where you require the wider ½" to 4" connection range, a choice of construction materials or larger industrial pipe sizes.
Choose APT where you require a compact ½", ¾" or 1" stainless steel CF8 big-chamber arrestor for water systems operating within its 10 kgf/cm² working pressure and 0°C to +60°C temperature range.
Pressure:
1 Bar, 1.2 Bar, 1.3 Bar, 1.4 Bar, 1.5 Bar, 1.6 Bar, 2 Bar, 2.5 Bar, 3 Bar, 3.5 Bar, 4 Bar, 4.5 Bar, 5 Bar, 5.5 Bar, 6 Bar, 6.5 Bar, 7 Bar, 7.5 Bar, 8 Bar, 8.5 Bar, 9 Bar, 10 Bar, 12 Bar, 13 Bar, 14 Bar, 15 Bar, 16 Bar, 17 Bar, 18 Bar, 20 Bar
Media:
Fluid (Non Aggressive), Water, Water (RO/Pure/Demin)
Body Material:
Bronze, Stainless Steel
Port Size:
1/2 thread, 3/4 thread, 1 thread, 11/2 thread, 2 thread, 21/2 thread, 3 thread, 4 Inch
