1 November, 2015

How It Works

During periods of heavy rainfall storm sewers can become overloaded, or surcharged. This can result in foundation seepage or, worse, storm and sanitary sewage back-up into basements where combined storm and sanitary system exist. Developed by the Department of Civil Engineering at University of Ottawa, inlet control devices (ICDs) have been used by sewer designers to preserve sewer capacity during peak flow events by restricting the flow from certain catch basins. The ICD, whether frame & sliding plate style, plate only, or plug style, is fitted over or in the lateral outlet pipe at the bottom of the catch basin. It has an orifice of a particular size and shape. The size determines what the flow rate will be at a given head. The “keyhole” shape serves three purposes.

First, the compound orifice shape promotes a self-cleaning action in debris laden flows, especially important in the critical early stages of flow capture. As the catch basin fills and the hydraulic pressure builds, the sharp corners of the orifice contract the flow, centering debris as it passes through the orifice.

Second, the slot at the bottom of the orifice induces a strong vortex action in the approach flow during periods of heavy rain. This vortex action scours sediment from the sump of the catch basin and away from the orifice.

Third, during dry periods, the slot at the bottom of the orifice draws water below the main orifice area. Floating debris is kept clear of the opening, reducing the likelihood of damming, and less debris passes from the catch basin into the main sewer.m

The simple, yet very effective design of the CANADIAN CONTROL DEVICES inlet control device has proven itself since 1984. The design of our framed ICD allows for the drainage of sediment from the channels in which the plate is held. For times of sewer maintenance the plate can be easily removed and replaced with the use of a hook from street level.