How the RTube Works

The RTube is strictly a non-rebreathing device and utilizes two one-way valves to maintain unidirectional flow throughout the entire breathing cycle as the subject inhales and exhales through the mouthpiece. As the subject breathes normally through the device, saliva is separated from the main exhalate stream in the blue "Tee" section of the mouthpiece and directed downward with the assistance of gravity into the saliva drain. From here the saliva exits the device through the one-way disc valve at the bottom of the "Tee" section. The exhaled breath stream turns upward and passes through a one-way duckbill valve into the gray condensation tube. The peak of this duckbill valve is a long, thin slit which acts as a nozzle.

Turbulence is created by the nozzle as the air jet spreads out into the cylindrical condensation chamber. The asymmetric placement of the air jet within the condensation chamber directs proportionally heavier flow to hit the cylindrical surfaces parallel to the plane of the diagram below. The imbalance of flow and pressure redirects the jet to form vortexes which periodically mix. This ensures maximum impaction of suspended particles with the tube wall and greatly enhances the heat transfer from the exhalate to the tube.

The effect is easy to test: during use place your hand above the top of the RTube as you exhale. Your exhaled breath will feel cool. Remove the duckbill valve, re-freeze the cooling sleeve, and try again. This time your breath will feel warm even though you are using a fully-chilled cooling sleeve. The difference is the absence of turbulence normally created by the duckbill valve. Warm exhaled breath means lower heat transfer, less condesation, and therefore less sample yield. While many homebuilt devices can be found in the literature, none of them will yeild the efficiency of time and quality of sample you will get with the RTube.

Quality

Our commitment to quality extends far beyond our product. At Respiratory Research, Inc., it is a way of business. We require that leading industry quality practices be applied to all products and processes. This includes Supplier Qualifications, Engineering, Procurement, Manufacturing, Order Fulfillment, and Technical Support.

We work with ISO 9000-certified suppliers only. Top-tier suppliers are provided current engineering documentation at all times and apply their own internal quality systems to ensure that all products supplied to Respiratory Research, Inc. are in full conformance with these engineering specifications. Respiratory Research, Inc. thoroughly and completely documents all product requirements using engineering drawings bills of material, assembly procedures, environmental specifications, and component specifications. These are maintained by Respiratory Research, Inc. and are under full revision control.

We leverage the established quality systems of top-tier ISO 9000 suppliers. The core quality function is performed at the integration facility under the control ISO 9002 certified suppliers. This requirement is applied to all top-tier vendors who manage operations performed under their control. They in turn drive their quality program through their sub-suppliers per their ISO 9002 documented processes and procedures. We periodically perform a full and thorough inspection of randomly selected incoming material tied to a particular batch. Additionally, the first production batch received from any new supplier is 100% inspected. Respiratory Research, Inc. also periodically audits top-tier suppliers to ensure that their documented quality systems continue to be followed. All results from our in-house inspections and supplier audits are fed back to the suppliers and closed-loop corrective action plans are established as needed. Additionally, we aggressively collect field data on the performance of our products and use this information to drive constant improvement in our design, delivery, and post-sale support.

Our commitment to you is simple: We will do everything we can to ensure the success of your study. That means perfect product, on time, every time, supported as long as you need us by the world's experts in Exhaled Breath Condensate.