Frequently asked questions and practical tips –
we are happy to help
Whether in everyday life or in a professional environment, practical tips can make the decisive difference. Here we have put together practical tips for you, which may help you as a first step or give you an answer. We will extend the number of tips in the future. If you have any further questions, please get in touch: eckard.brandau@chemec.de
The choice of material depends on many factors that must be evaluated depending on the project:
1. Composition of the sample gas
2. Temperature and the pressure of the sample gas
3. Ambient temperature
4. Incidence of UV light (sunshine)
5. Budget
6. Other factors
As a general rule, stainless steel tubes or plastic hoses are available.
If you have any further questions, please get in touch: eckard.brandau@chemec.de
Advantage: Stainless steel is mechanically robust and particularly advantageous for sample lines outside buildings. We recommend an internal diameter of 8 mm due to the robustness.
Disadvantage: High material and assembly costs. Some gases, such as H2S, are prone to adsorption on stainless steel surfaces. Therefore, if concentrations fluctuate greatly, time delays may occur.
Conclusion: Plastic tubes are generally less expensive than stainless steel tubes, but with this solution you should pay more attention to chemical resistance, UV resistance and the price; not every hose material is inexpensive to buy. With regard to chemical resistance, we recommend the resistApp from the company Bürkert, www.burkert.com, which is available on the Internet in many languages.
If you have any further questions, please get in touch: eckard.brandau@chemec.de
Advantages: Plastic hoses are much cheaper as a material and to assemble than stainless steel tubes. The risk of adsorption in plastics is lower than in stainless steel. Some plastic hoses are available in different colours. If the sample gas connection hoses differ in colour, this simplifies maintenance.
Disadvantages: Plastic hoses are mechanically less robust than stainless steel tubes, can age, i.e. become brittle, kink or discolour, and are much more sensitive to local heat sources.
Conclusion: Plastic tubes are generally less expensive than stainless steel tubes, but with this solution you should pay more attention to chemical resistance, UV resistance and the price; not every hose material is inexpensive to buy. With regard to chemical resistance, we recommend the resistApp from the company Bürkert, www.burkert.com, which is available on the Internet in many languages. www.burkert.com, die im Internet in sehr vielen Sprachen verfügbar ist.
If you have any further questions, please get in touch: eckard.brandau@chemec.de
The most common materials are PE, PA, PP, PVDF, PTFE, as well as PVC and PU.
PE, PA, PP, PVDF and PTFE generally have high chemical resistance, but we recommend testing based on recognised resistance lists, e.g. resistApp.
With PVC, please note that the basic plastic is hard and brittle and is only suitable for hoses if chemical additives are used, such as plasticisers. These must not be attacked by the sample gas. We have had good experience with hoses suitable for laboratories.
PU hoses are manufactured for air-powered pneumatic equipment and are available in a range of versions. However, we do not have any chemical resistance information, so we advise you to be careful when using these as gas sample hoses.
If you have any further questions, please get in touch: eckard.brandau@chemec.de
We use PE hoses. These have very high chemical resistance and are inexpensive, flexible and available in multiple colours.
In the GAS device as well as indoors, we always use yellow hoses, which can be clearly distinguished from electrical cables. The yellow also stands for gases.
Outside buildings, we use black PE hoses because they are resistant to the UV light of the sun.
All hoses have an internal diameter of 4 mm.
If you have any further questions, please get in touch: eckard.brandau@chemec.de
Open to all questions: stay in touch
Do you want to know what is possible or have questions and would like a non-binding advice? The best way is an initial conversation. We will be happy to help you with personal advice.
Chemec GmbH
Meisenstraße 96
33607 Bielefeld
Germany
Phone +49 521 2997-430
Fax +49 2997-431