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In an engineering project with highly corrosive substances, such as hydrochloric acid, it can be difficult to find the right components. The requirements for joints, fittings and hoses are strict and at the same time costs always play a role. The impact of a wrongly chosen component is large and finding the components takes a lot of time. Teesing believes that we help engineers better by making the system configuration together, because we understand flow.



Zeton came up with a concrete demand for the supply of a number of compounds for a pilot plant (test plant) for the chemical industry. However, when it turned out that it was an application with hydrochloric acid, things were more complex than initially thought. We offered to configure the subsystem and this was gratefully accepted. This chemical pilot plant included eighteen points where samples could be taken from the product, so that the process could be monitored at various points. Our starting point was the customer's P&ID.

Plant chemisch
Example of a pid


Spleetcorrosie bij rvs
Crevice corrosion in stainless steel


Stainless steel versus PVDF

Stainless steel components fall off because hydrochloric acid causes crevice corrosion in stainless steel. Crevice corrosion is particularly dangerous because it usually occurs under the surface or in joints, making it invisible. What are the alternatives in this case? Materials that quickly come to mind are plastics and highly alloyed metals such as Hastelloy. Because Hastelloy is expensive and difficult to process, PVDF couplings from Serto and PTFE hoses were chosen. PVDF has advantages in this case:

  • Very high chemical resistance
  • Less expensive than stainless steel
  • Suppliers who can supply PVDF couplings smaller than ½" in diameter are scarce, but Serto has an extensive range.


Coupling from glass to plastic

A second complicating factor is the combination of glass and plastic. People want to use glass jars at the points where samples are taken, because this is the standard in the laboratory where the samples are processed. These sample jars are made of boron silicate with a GL thread coupling. The connection from tube to glass is very well possible, but deserves attention.

Dry-break couplings for hydrochloric acid

The third challenge is the requirement that the system must be easy to disconnect at various points. For this, dry-break (or non-spill) couplings must be used. These are couplings that we often sell, but for hydrochloric acid there is a lot involved. All wetted components must be sufficiently chemically resistant. Therefore, in this case the non-spill coupling made of PP (from the manufacturer CPC) is used. These PP couplings have been modified: the standard stainless steel spring which is attached to the valve and which in most cases complies, has been replaced by a Hastelloy one.


PFA slang in CO2 sensor kop

Engineering or sourcing?

This project is at the edge of engineering and sourcing. Teesing represents the world's most respected manufacturers of couplings and fittings. In doing so, we are independent. The application of the components determines the choice for a manufacturer; not the delivery possibilities of manufacturers. People like to work with Teesing because:

  • We think along on a mechanical and chemical level (in different technical disciplines).
  • Selecting suitable components (application, cost price, delivery time).
  • We design complete subsystems.
  • Teesing is brand-independent.


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More information?

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