On January 22, 2010, Allen Worst presented to a group of complex installers and Panhandle Health District employees the value of RCW's patented continuous flushing drip system related to distribution of effluent for residential and commercial applications. Allen is Vice President of R.C. Worst & Co. in Coeur d'Alene. The presentation took place at the Panhandle Health District's office at their North Atlas location in Hayden Idaho. R. C. Worst & Co. developed the system primarily for cold weather climates to more effectively and efficiently distribute effluent in drip systems that are susceptible to freezing.
Conventional automatic drip disposal designs typically use solenoid valves to provide dosing and flushing as two separate cycles of system operation. The drip field dosing cycle provides low flow dosing to the drip emitters at a pressure sufficient to provide constant flow throughout the field. A solenoid valve is activated on the return side of the field piping network to activate the flushing cycle. The additional velocity creates turbulent flow which is designed to scour any solid material from inside the drip tubing and manifold piping networks. This material can be wasted back to the septic or dose tank as necessary. An additional solenoid valve is often incorporated to provide flushing of the system filter which helps to extend the mean time between manual filter cleaning.
In addition to flushing functions, solenoid valves also must provide a means to drain a system protecting from freezing in cold climates. However from a hydraulic standpoint, the typical drip system solenoid valve only provides a limited ability to fully open and fully close under low pressure conditions. Therefore the need to rapidly drain the entire field and manifold networks can not be met with the conventional system design. Furthermore solenoid valves have proven to be mechanically unreliable in the effluent application.
As a solution both flushing and dosing cycles were combined into one phase using a fixed orifice to split and balance flows thereby eliminating the problematic solenoid valves altogether. This design allows rapid, unimpeded system drain-back paramount to reliable cold weather operation. An additional fixed orifice was added to provide constant flushing of the system filter thereby allowing the system to a) dose the drip field, b) flush the drip lines, and c) flush the filter simultaneously. Of over twenty systems monitored which were originally implemented soon after regulatory approval in Idaho and Eastern Washington, none to date has had a single freeze related problem.