Flow Design, Inc. - A History of Leadership and Innovation


Flow Design Inc. has been leader in the hydronic balancing industry since it began manufacturing flow limiting valves in 1978. FDI has continually developed new products offering superior performance benefits and has established a reputation for outstanding quality.

One of the earliest contributions was the introduction of the brass-bodied flow limiting valve. This feature eliminated dissimilar metal corrosion common to many piping systems. Other features of these early models included the union body for easy access to the valve internals and an integral ball valve assembly for the reduction of installation costs.

In 1979, the company began selling pressure/temperature test ports. Flow Design, Inc. introduced the retainer cap strap, in 1991, the patented dual durometer inner seal which prevents seal abrasion and provides superior close off.

The FlowSet venturi based manual balancing system was introduced in 1987. These simple devices offered two major benefits: low head loss (one foot or less) and direct GPM readout. Low head loss saves energy because a smaller pump impeller can be selected and direct readout in GPM improves balancing accuracy. Models are available which can read flow as low as 0.1 GPM.

Since 1990, FDI has offered contractors factory assembled coil Hook-Up modules. These space saving modules contain all the components needed for a complete coil Hook-Up. FDI even allows contractors to ship temperature control valves to the Dallas factory to be included in the Hook-Up kit. These kits are extremely cost-effective as they require less field labor at installation and because the Hook-Up are 100% leak tested at the factory, resulting in fewer call-backs.

In 2000, FDI was purchased by IMI plc in the UK. Afterward, FDI joined the IMI Indoor Climate group.

FDI is dedicated to testing its products to insure the highest quality and has one of the largest test loops (to 12,000 GPM) in the Southwest. The test facility is used to check production as well as to develop new design concepts.



Flow Design’s engineering innovation has resulted in the aforementioned patents as well as others, including these highlights:


  • Multiflow – Flow regulating control valve and method for regulating fluid flow
  • SuperVent (Air Vent/ Superseal combination) – Combination air vent/probe port and method of constructing same
  • Flow Shaper: enhanced venturi product. – Apparatus and method for shaping fluid flow
  • AutoCheck: AutoFlow with protection feature to close the pipe if there is a catastrophic failure (used for hoses in fire protection systems) – Method and apparatus for regulating and terminating fluid flow
  • AutoFlow: Very low flow variant – Enhanced solid piston flow controller
  • AutoFlow: Low flow variant – Flow control valve with enhanced flow control piston
  • AutoFlow: End ports for improving start-up – Constant flow rate control valve with low pressure drop start
  • AutoFlow: Startup slots used in canister product – Constant flow rate control valve with low pressure drop start
  • SuperSeal: – Valve test plug


Innovative new engineering and manufacturing techniques, dedication to quality and continued growth assure that Flow Design, Inc. will continue to be a leader in the hydronic balancing industry.