TTT - Thistle Tube Throttle

The Hydrovex® TTT Membrane Flow Regulator produces a nearly constant discharge rate as upstream water levels rise and fall.  It is an ingenious demonstration of the Bernoulli principle wherein an increase in velocity is offset with a corresponding drop in pressure. The Hydrovex® TTT features a resilient neoprene membrane stretched over a PVC tube with specially designed oval shaped slots cut from each side of the tube.  As upstream water levels rise and water begins to flow through the tube, the pressure outside of the tube becomes greater than the pressure inside the tube and the neoprene membrane is pressed into the interior of the tube.  This reduces the cross sectional area of the tube and maintains the discharge at a nearly constant flow rate.

The Hydrovex® TTT has a proven track record of successful installations in North America dating back to 1985 which demonstrates its extreme reliability and long service life.

The Hydrovex® TTT is available in two different types:

  • Type I is designed for a wet installation on the upstream side of the discharge location in a storage facility, such as a detention pond, vault, tank or manhole.

  • Type U is designed for a dry installation in a chamber on the downstream side of the discharge location in a storage facility.
Hydrovex® TTT-I Installation 
with slide gate and pull cable
Hydrovex® TTT-U Installation
The Hydrovex® TTT can be configured to deliver nearly constant flow rates between 0.1 cfs and 2.4 cfs, and multiple units can be combined to produce larger flow rates. 

The Hydrovex® TTT can be configured for a variety of installation conditions depending on your specific project requirements.  Available connection options include:

  • Slide gate connection with 304 stainless steel frame and pull cable, or

  • Standard ANSI flange pipe connection, or

  • Plain end for solvent weld connection.

A turned down inlet is also available for floatables control.

The Hydrovex® TTT is an ideal solution for the following design problems:

  • Minimizing detention storage volume

  • Flow Splitting

  • Flow Throttling