Frequently Asked Questions

Q. What is a Hydro-Brake^® Flow Control?

A. A Hydro-Brake^® Flow Control is a no-moving parts, self-activating vortex flow control. When the upstream water level reaches a suitable level the water entering the unit spins within it. This causes the formation of an air-filled core which takes up a significant proportion of the outlet of the unit. Water discharges around the periphery of the outlet from the Hydro-Brake^® Flow Control only which enables the use of a significantly larger outlet than if a simple orifice was used. The outlet cross-sectional area can be greater than 400% of that of the equivalent orifice required to meet the same head / discharge condition.

Q. Do they work under downstream surcharge conditions?

A. Yes, but an air vent pipe may be required to ensure that the air core can form. The flow through a Hydro-Brake^® Flow Control is dependent upon the physical size of the unit itself and the differential head of water acting upon it.

Q. How much maintenance does a Hydro-Brake^® Flow Control require?

A. Quite simply, this is site-dependent. It depends upon the size of the Hydro-Brake^® Flow Control itself (the larger the unit the less the likelihood of a blockage occurring), the nature of the influent (for example a unit of a given size would be more susceptible to blockage were it placed on a foul system than on a purely surface water system) and physical characteristics of the control chamber itself (adequate benching is essential). We have minimum recommended sizes for use within surface and foul water systems and a range of Hydro-Brake^® shapes, each having defined discharge characteristics, to ensure that we tailor the most suitable unit to the specific site conditions in question.

Q. Why should I use a Hydro-Brake^® Flow Control as opposed to a simple orifice which is cheaper?

A. There are many benefits in using a Hydro-Brake^® Flow Control. Firstly the outlet cross-sectional area of a Hydro-Brake^® Flow Control is typically four times that of an orifice which should result in a significant reduction in the likelihood of a blockage occurring. Thus maintenance costs and problems are also reduced. Secondly, at low upstream heads experienced in the early stages of a storm the vortex does not initiate. Consequently higher flows are passed forward than were an orifice installed (as the Hydro-Brake^® Flow Control outlet is larger) and this results in less water being held back in storage. This means that a smaller storage tank can be used with associated cost savings. Typical volume reductions can range from 5 – 30% depending upon the system layout / design storm characteristics.