how do they work?
Umbrella/duckbill combination valve can be applied in two different ways.
irst as a combined air inlet and pressure-relief valve. Imagine this part is fitted in a container, for instance in a fuel tank. When the engine consumes fuel the duckbill valve lets air in the tank at low-pressure differential in order to replace the fuel and prevent from creating a vacuum in the tank. When the tank is held upside down such as with a chainsaw or something like that, the duckbill shuts the vent hole and prevents fuel dripping out. On the other hand when the tank gets hot and fuel vapors pressure is building in the tank the umbrella valve opens and vents the gasses to atmosphere or to a charcoal filter if you like. Two functions in one part by just mounting the valve in the cap or wall of the tank.
The other application is one where the duckbill and the umbrella direct the flow to separate chambers or conduits. In this way the one component can provide two valve functions, for example when used in a piston or diaphragm pump. In the inlet stroke the umbrella opens up. Then, at the outlet stroke, the umbrella shuts off and the fluid is directed through the duckbill valve. One component, two valves. The advantage is further that when used in a dispenser, the higher opening pressure of the umbrella may serve as an anti-dripping valve or head-pressure valve as well.
Umbrella/duckbill combination valves have been around for many years. Their applications include vessel vent valves such as for automotive fuel tanks, in-and- outlet valves for piston and diaphragm pumps, two-way vent valves in venous reservoirs and numerous other fluid control functions in medical devices, home appliances, cars and toys.
Minivalve(tm) umbrella/duckbill combination valves work with a specific seat design which is to be integrated into the metal or plastic application. In order to find the proper seat design and thickness you may use our preferred seat design instructions and adapt them further to your specific needs. For example if your valve needs high flow then you make the flow orifices in the seat as large as possible even with slots in the shape of a banana. On the other hand if your valve has low flow or needs to withstand high backpressure, you need only to apply one or more small flow orifices and take care that the outside diameter of the flow surface area doesn't get too close to the edge of the umbrella in order to make sure that there is enough seat surface area to support the diaphragm under backpressure.
Minivalve™ Umbrella/Duckbill Combination valves are available in various elastomeric material including medical and food-grade silicone and hydrocarbon-resistant fluorosilicone rubber to handle a broad range of media and temperatures.
Minivalve International is a niche company dedicated to the development, manufacturing and worldwide distribution of a broad variety of miniature, self-actuating valves and elastomeric valve components for OEMs. We have specialized in automatic high-volume manufacturing and offer our own range of standard umbrella and duckbill valves from our catalog. They are supplied off the shelf in several sizes and materials. That means they are readily available in any quantity, from a few to millions of parts per year. We also develop customized valve solutions.