How measuring felt thickness revolutionized nip dewatering

How it all started!
The Caliper Profiler was Feltest’s first product ever. Actually, it was the spark that started the founding of Feltest as a company!

Back in the 1980’s my father, Nick Lensvelt, was a felt application engineer for one of the world’s leading Paper Machine Clothing manufacturers. In those days the performance of press felts was judged only by looking at the sheet. After installation, felt properties were no longer measured or monitored; nobody really knew what was happening once the felt was running.


The introduction of nip dewatering

It were also the days that grooved press rolls were introduced: the introduction of nip dewatering! With nip dewatering a new question arose: why do felts have a startup or break-in period? My father has a very analytical background and not only wanted to see WHAT happened with the felt, but he also wanted to understand WHY. The only tools available, the Scanpro© Jetmem and the vacuum level on the Uhle box, where not giving him the information he needed to solve this puzzle.


The first in measuring thickness of felts

designed an instrument that could accurately measure the thickness of a running felt. With its pistol-like handgrip it drew quite a bit of attention.



With the new information the instrument supplied, it became very clear to Nick Lensvelt that the mid-nip caliper is an extremely important felt property. He started designing thinner felts that generated more nip dewatering, higher sheet dryness and shorter break-in periods. The productivity of the paper machines increased considerably!


In the early nineties Nick Lensvelt accepted a position with another PMC manufacturer. This new company had no intention to start manufacturing measuring gear as well, so it was agreed that Nick Lensvelt would manufacture it himself and the company would buy it from him. With all his experience from the first model, Nick Lensvelt started sketching an improved version and asked me to do the engineering work. Nick Lensvelt and I still had to think of a name for our new established company. I didn’t lose much sleep over that: the instrument is developed for a “felt test”, but then a bit more stylish, so “FelTest” is what it became!


measuring felt


The first Feltest Caliper Gauge was sold in 1992

In 1992 we supplied the first instrument to this European PMC supplier and, as they say, the rest is history. Nowadays Feltest has sold hundreds of pieces of the classic Caliper Gauge and today’s Caliper Profiler all over the world. Nick Lensvelt’s bright idea, back in the eighties, for sure contributed to the success of the concept of nip dewatering felts. It enabled Nick Lensvelt and many other felt application engineers over the world to study the effect of felt compaction and to differentiate compaction from contamination (for more details on this, check out the whitepapers or watch my most recent presentation).


The Caliper Profiler as foundation of quality measurement today

For me personally, designing the caliper gauge in 1992 was the start of successful cooperation with my dad that lasted over a decade. It was the start Feltest Equipment BV, today offering a wide range of innovative products to satisfied customers in over 70 countries.

The Feltest Caliper Profiler is a unique and high quality product based on decades of innovation, which enables papermakers to make fact based decisions and to get the best possible performance of their press felts!


This makes the Caliper Profiler for sure the first Product of the Month. So if you want to reduce the break-in period or increase the felt life, get your quote here.



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