Twenty years of proven field operation, research and development, and continued engineering enhancements have combined to make the Tideflex Model TF-1 today’s most reliable duckbill check valve. The bill design is formed in a curve that returns to a closed position every time, achieving the tightest possible seal for backflow applications, particularly at low flow rates. The eccentric flat-bottom design allows installation where the invert of the pipe is close to the floor, and the stronger engineered spine provides long-term performance while handling long-term water weight. No other manufacturers can produce this design with these state-of-the-art features.  When you specify the Tideflex TF-1 Curved Bill Check Valve, you’re guaranteed to receive a product with a proven record of maintenance-free backflow prevention. 

Protecting And Improving The Performance Of Effluent Outfalls(10) 4" Series 35D's with integralwire-reinforced rubber risersfor an industrial outfall in the Ohio River(25) 3" Series 35D's on a MarineOutfall in the Caribbean(12) 42" TFD's on a multi-port EmergencyOutfall located in Hong KongTideflex Technologies’ developed a special series of Tideflex Duckbill Check Valves called Tideflex Diffuser Valves (TFD). TFD’s differ from standard Tideflex because TFD’s are custom-designed for every outfall based on jet velocity, open area and headloss requirements that are critical to achieving the required initial dilution within the hydraulic head limitations of the outfall. There are up to 50 different hydraulic variations of TFD’s per nominal size. An extensive amount of independent hydraulic testing was required on many sizes and stiffness of TFD’s to develop the hydraulic models Tideflex engineers use to assist in the design of multiport effluent diffusers.
​ TFD’s have been extensively utilized on inland and marine multiport effluent outfall diffusers for over 20 years - municipal and industrial applications including chemical, pulp and paper, power (thermal-heat dissipation), textile (dilution of color), lumber, agricultural, food, pharmaceutical, plastics, metals and fertilizer.
​ Multiport effluent diffusers were conventionally designed with fixed diameter open ports but open ports allow backflow of sand, silt, debris and salt water which reduces the hydraulic capacity of the outfall and compromises the initial dilution. The cost to clean out the outfall and restore to service is excessive and the potential for future cleanout still exists as the marine environment cannot be controlled. TFD’s prevent the backflow of sand, silt, debris and salt water into the outfall thereby preserving the hydraulic capacity and dilution efficiency of multiport effluent diffusers.
​ TFD’s also have a hydraulic advantage due to the inherent variable orifice characteristic– the TFD’s progressively open/close with increase/decrease in flow. The benefit, compared to fixed diameter ports, is higher jet velocity at lower flows and less headloss at peak flow. The optimized jet velocity yields improved near-field mixing and dilution and the reduced headloss increases the hydraulic capacity of the outfall. TFD’s have also proven to produce a more uniform flow distribution among ports.
​ TFD’s are installed on new outfall diffusers and are easily retrofit to existing outfalls. Red Valve engineers run hydraulic models to optimize the quantity, size, and relative stiffness of the TFD’s to meeting the hydraulic and dilution requirements of the diffuser. The data supplied can be directly input to environmental impact assessment models such as CORMIX and Visual Plumes.

Introduction To Tideflex Technologies Aeration Systems And ProductsTideflex "Check Valve"Coarse Bubble DiffuserTideflex Technologies has developed a number of systems designed to provide enhanced mixing and oxygen transfer through gas diffusion technology.  The two major categories for gas diffusion are 1) high efficiency oxygen transferring fine bubble and 2) high mixing energy coarse bubble.  For anoxic mixing requirements the use of hydraulic recirculation systems utilizing high velocity discharge nozzles are most effective.  Tideflex Technologies provides systems utilizing each of these methods on their own as well as systems where these methods are combined to achieve the best aspects of each method type.  This progressive approach to mixing technology allows for each application to be optimized for performance.
​ The Tideflex backflow prevention technology has been incorporated into all the individual products which means that a Tideflex System will have the highest performance with the lowest operational maintenance requirements.  Tideflex Technologies is leading the industry in mixing technology for hydrodynamic design and diffused gas design; refer to the specific pages on Mixing Technology and Diffused Gas Technology for additional information.
Extremely low headloss 
Durable 100% elastomer construction
Easily installed in any type of pipe
No menchanical parts
​4" (100 mm) - 72" (1800 mm) size
25  year life expectancy
​Operates on differential pressure
Virtually maintenance-free
Less than 1" of head pressure cracks open valve
Eliminates standing water
Silent, non-slamming
Simple installation
Extensive independent hydraulic testing
​Opens to near full pipe diameter

Materials Of Construction
Elastomer Information
Expansion Clamps: 304 Stainless Steel (Standard)           
316 Stainless Steel           
Special Alloys Available
Valves & Equipment Manufacturers Representatives
Tideflex Technologies
A Division of Red Valve Company, Inc.


Tideflex Technologies was the original inventor and manufacturer of duckbill style check valve and has continued to enhance and refine the design and performance of this product.  The duckbill check valve is inherently a variable orifice device which changes it's effective opening area with respect to the internal pressure and mass flowrate through the unit. This flexibility can be incorporated into the design of the unit so that it will also perform as a variable flow nozzle. Enhancing velocity discharge and momentum within a fluid body is the key in achieving adequate mixing. Along with designing duckbill check valves for non-restrictive backflow prevention, Tideflex

Technologies alos designs and manufactures mixing systems which utilize this variable orifice technology and the unique Tideflex Hydrodynamic Nozzles.​