Oscillatory Pressure Wave Systems for Ventilators -

Oscillatory Pressure Wave Systems for Ventilators

Can this alternative approach help meet increased demand?

As COVID-19 creates the need for hundreds of thousands of ventilators, finding alternative systems for ventilators could help by using different components and resources that are still available. Thousands of engineers, scientists and others are collectively working to find new approaches to the shortage. 

We at Equilibar are working in our lab to see if we can develop an alternative strategy for ventilator system designs that might enable other innovators. We are working with several partners around the world to learn if there is a place where we can contribute. Our goal is to publish multiple parallel approaches and solicit feedback from early adopters worldwide. We will start with the products we know best, but also include several other approaches. We are preparing right now.

Please contact us with questions or comments at inquiry@equilibar.com 

Defined Pressure Wave System

An alternative approach to the mechanically compressed volume system is a defined pressure system. In this approach, an ultra- sensitive dome-loaded back pressure regulator is used to provide highly controlled inhalation and exhalation pressure waveforms. Dome-loaded means that gas or air is fed into the top (dome) of the regulator to provide the pressure waveform setpoint. This waveform setpoint can be supplied either from an electro-pneumatic pressure regulator (EPR), or through simpler mechanical means. These secondary pressure regulators are called pilot regulators.

Simple Automated Pressure Wave System

This design uses commonly available solenoid valves along with simple pressure control components we believe can be mass produced. A waveform signal working in combination with some solenoid valves provides a simple automated approach to generating a defined pressure wave system.

It starts with an on-off waveform signal sent to two simple solenoid valves. One controls flow from the oxygen enriched air supply to the patient and the other controls flow to the dome of the sensitive dome-loaded back pressure regulator (BPR). See schematic below.

schematic of simply automated pressure wave control

Also controlling the air flow to the dome of the BPR is a bleed valve. As the solenoid valve opens and closes, the dome setpoint pressure alternates back and forth between the lo pressure mbar pilot regulator (open) and the hi pressure mbar pilot regulator (closed). This alternating pressure rhythm on the dome of the BPR provides the setpoint for the air going to the patient. The result is a controlled pressure rhythm from the enriched air supply to the patient. The solenoid to the patient opens in a reverse pattern from the pilot solenoid. The patient solenoid opens during hi pressure to allow air to fill the lungs, and closes during lo pressure to allow lungs to exhale.

Because the sensitive dome-loaded BPR technology provides nearly instantaneous response to pressure setpoint changes, it works extremely well for waveform pressure control.

A video from the lab demonstration is below. 

Please contact us at inquiry@equilibar.com with questions or feedback. 

Fully Automated Pressure Wave System

In an earlier version, a fully-automated pressure wave system was created using a programmable logic controller (PLC) in combination with an electro-pneumatic pressure regulator (EPR). It starts with a configurable waveform signal output from a PLC that includes pressure and rate (in breaths per minute) to mimic inspiratory and expiratory rhythm. These components may not be as readily available to some people, but if interested, read about it on this page. 

Manual Pressure Wave System

In another version, a manual pressure wave system was created using a hand pump and a mechanical pilot regulator constructed in the Equilibar lab. With a simple hand pump and good rhythm, a manual pressure wave system can be built.

Related Products*

Oblique view of ultra-sensitive dome-loaded back pressure regulator

Ultra-sensitive dome-loaded back pressure regulator RV-22

RV-19 sensitive dome-loaded BPR Oblique image

Ultra-sensitive dome-loaded back pressure regulator RV-19

photograph of RV-22 dome-loaded regulator

photo of RV-19 sensitive back pressure regulator

photograph of RV-19 dome-loaded regulator

Related Pages

schematic of Oscillatory Pressure Wave System for Ventilator

fully automated pressure wave system

schematic of manual oscillatory pressure wave system

manual oscillatory pressure wave system

*Equilibar control valves have historically not been for use in commercial ventilator systems. In connection with the COVID-19 pandemic, Equilibar has retrofitted its valves for potential use in connection with medical ventilator systems. While our valves are not approved for any medical use by the FDA or any other governmental agency, Equilibar plans to produce these valves in volume and offer the valves, with affordability in mind to the extent possible, to businesses or governments who are actively seeking or agree to seek qualifying approval for the sale or distribution of integrated systems for use within a medical setting from the U.S. Food & Drug Administration (“FDA”) or other similar governing agency in local jurisdiction. Your agreement to any terms of sale with respect to our valves asserts that you are a technically competent entity capable of evaluating system risk and seeking Emergency Use Authorization from the FDA or other similar governing agency in local jurisdiction.

All rights to use our valves shall be effective from the date we provide the valves to you until such time as we notify you that your use must end which reasons may include, without limitation, end of the existing pandemic or recalls for safety reasons.

Use of our valves and/or drawings shall be solely as provided for in a legal agreement with you which will include, in part that any sale is (i) not and does not represent medical or legal advice by Equilibar, (ii) is not approved or available as alternative to an FDA approved ventilator and (ii) AS IS, WHERE IS, AND WITH ALL FAULTS’’. If you do not agree with any of the foregoing do not purchase or use any of our valves for use other than as originally intended (i.e. commercial ventilator systems).

Equilibar News
Oblique view of ultra-sensitive back pressure regulator

COVID-19 Update: Equilibar working with ventilator designers to increase access to component parts

Since Friday March 20, 2020, Equilibar has focused on working to modify the design of our fluid control valves to enable them to serve as building blocks for medical ventilator systems.  Our technical team has made rapid progress.  Based on collaboration with bio-engineering and medical experts, we believe we have developed designs that can contribute Read More

Read More