One of the challenges in designing products with springs is figuring out exactly what you need for a spring: You know what you want the spring to do—but what will the spring look like? How big will it be? What material will it be made of?
One option involves getting in contact with one of several suppliers for so-called catalog springs. Often, they can get you close to what you need—on a lucky day you’ll find exactly what you need, and when you only need a handful of a product, buying from a catalog is often a good way to go. (Truth be told, we’ve bought catalog springs ourselves.) But when you need a specific spring and you need the spring in mass production quantities, you need a custom spring manufacturer like Maverick Spring Makers Limited.
Take, for example, our new friends at Twothirds Water, where they’ve been working on a better water filter. Bradley Pierik, the founder of Two Thirds Water comes from a background where the goal isn’t that everyone uses a certain technology to filter water, but that everyone has clean water. We like that. We think that is a healthy, forward thinking way to develop a business. Twothirds Water has a water filter design that we think is world class, and will change—for the better—lives all over the world.
In the organization’s TAPP water filter, there is a simple spring loaded ball check valve to control the water flow. In the development stages, Twothirds Water used a zinc-plated music wire spring with ground ends that they sourced from an industrial supply catalog. The spring gave the physical performance required, but for a spring that will experience tens of thousands of liters of flowing water over the course of years, corrosion resistance is very important—and zinc plating isn’t going to be good enough, which is why they called us.
Since this is fresh water, Stainless Steel Type 302 is the best, most common, most economical place to start. To keep costs down, we advised against grinding the spring ends, which will save pennies per unit and thousands in the bigger picture. One of the challenges in spring design is that you cannot directly substitute Stainless Steel Type 302 for music wire. All other things being equal, a spring made with Stainless Steel Type 302 will be approximately 13 percent weaker than a spring made with music wire. As well, the stainless steel spring cannot be deflected as much as music wire before the spring takes a permanent set. To change to Stainless Steel from music wire, you will often need to change or increase the wire size, too. The final complication is that the spring is in the water flow. That is, if the spring is compressed to solid, water won’t flow.
Working with Twothirds Water, Maverick Spring Makers Limited has helped develop a spring that keeps the ball valve closed when it is supposed to be closed, allowing water to flow through when the valve is open and maintains acceptable flow rates. To top it off, this spring is much cheaper than buying a stock spring from a catalog.
For more information on our custom spring capabilities or to see how we can save you money, head over to our website.
All images courtesy of Twothirds Water.