About us

We are really proud of our products and our services. We believe in us, and obviously do the many clients who trust us. And not just today, but from the beginning, exactly since January 1st, 1971.

It all started with industrial gases. Industrial Gases: a simple name for a complex technology that has been found in virtually all industries sectors, in research as in production. But then as now the use of this medium requires a lot of experience and circumspection, and a maximum sense of responsibility.

L + T was established by engineers Friedhelm Ludewig and Heinrich Tillmann as „Ludewig & Tillmann Regel- und Sicherheitstechnik Gas” (that stands for “control and safety equipment gas“ with its headquarters in Dortmund-Barop. First there were designed and manufactured fittings and devices for the gas technology.

Shortly after the foundation in 1971 a production hall with 1,300 square meters and an office building with 600 square meters was bulilt on a 5,000 square meters property in Dortmund-Kley. Today, around 20 highly qualified employees are working there. L + T GASETECHNIK is now LT GASETECHNIK.

Efficiency, the absolute, even unconditional compliance with all safety regulations, and focusing on technologically pioneering fields of application, are the basis of today’s corporate philosophy of LT GASETECHNIK. Facts reflecting the will to meet all market demands, today and in the future.

LT GASETECHNIK today operates in two business segments:

  1. Development and production gas related equipment and gas process plants, such as
    1. Standard gas mixers
    2. Gas mixing plants
    3. Gas dosing plants
    4. Control and measuring systems
  2. Development and production of fittings, with a focus on
    1. Safety Devices
    2. Central Gas Supply

for nearly all gas types and for use a wide range of technologically advanced, consistently demanding applications.

We can for example

  • tap gases under control (cylinder manifolds and bundle systems, main pressure regulators for automatic or manual operation);
  • purify gases (filters);
  • regulate gas pressure (HP pressure regulators, dome-loaded pressure regulators,
    control loops);
  • safeguard gases against flashback and gas return (flashback arresters, decomposition arresters, quick-action shut-off valves);
  • analyse gases (sampled gas processing systems, analysers);
  • mix gases (gas mixers, mixing systems);
  • meter and feed gases (flow meters, ball valves, pneumatic valves, pipe flow
  • and finally, feed them to the point of use under control (tapping points pressure
    regulators and brackets, quick-action valves).

LT gas mixers are used to implement and optimise processes, particularly applications which demand the highest levels of quality and safety.

Hundreds – no, thousands – of LT gas mixers are have been delivered to the world for years, to some twenty countries in almost every corner of the globe.

Our company history

2019 The 40th gas mixer type advanced is successfully delivered
Handelsblatt, Stern and VDMA News report on LT GASETECHNIK
2018 LT is launching a joint project with the German Aerospace Center (DLR) and the Karlsruhe Institute of Technology (KIT) with the participation of Forschungszentrum Jülich (FZJ)
Two more industrial gas producers include LT products in their standard supply catalog
MEP Denis Radtke and Holger Kunze, Director VDMA European Office, visit LT GASETECHNIK
2017 A project which was funded by the German Federal Foundation for the Environment was completed successfully.
Very successful acceptance and commissioning of another high-performance system for a float glass plant in Thailand
National and international partnerships extended

Several gas companies add the extended LT product program to their standard supply catalog
Successful development and standardization of the gas mixer advanced


Delivery of five very different natural gas conditioners
LT broadens the scope of production to compact dome loaded pressure control units as well as other innovative solutions in the field of C&I and analysis technology

2014 Mr. Alfonso Castell is retiring and
Mr. Alexander Carl Hanf successes him
2010 The 30th LT high duty station for generating a gas mixture from N2 and H2 goes into operation at Saint-Gobain’s float glass plant in Egypt
2008 Jochen Weyer and Klaus Weyer take over 25% each of the KG. Klaus Weyer becomes the sole share holder of the holder company.
2005 Alfonso Castell is appointed as joint managing director
2004 Horst Weyer takes over the shares from Renate Sandhof and becomes the sole proprietor
2003 The management passes to the next generation: Klaus Weyer takes over. From then on the company orients itself towards international markets and focuses increasingly on large-scale gas related systems, a cornerstone of the company’s success
1999 The shares of Friedhelm Ludewig are purchased by Horst Weyer
1995 The company’s name is changed to L+T GASETECHNIK Klöpper-Waldmann GmbH & Co. KG. It continues to focus on gas technique systems
1991 Lotte Lore Klöpper-Waldmann, her company shares are transferred to her heirs, Horst Weyer and Renate Sandhof. Both of them become managing directors and replace Friedhelm Ludewig in this role
1984 One of the company’s founders, Heinrich Tillmann, leaves the company. Lotte Lore Klöpper Waldmann becomes major shareholder of the company. Friedhelm Ludewig remains managing director
1983 The “LTD-1” dome-loaded pressure regulator is launched
1980 The company expands: New premises with a 1,250 m² production facility and 600 m² office space are built in Dortmund-Marten. The company moves into its own production site.
1974 The product range is broadened with centralised gas installations and systems for regulating, dosing, measuring and controlling gas pressures and gas flows
The “THERMOMAT” flashback arrestor is launched. The first LT gas mixer goes into operation
Friedhelm Ludewig and Heinrich Tillmann found
LUDEWIG + TILLMANN oHG in Dortmund-Barop.
The company focusses on design and manufacturing of fittings and machines for the gas technology. One year later the company is renamed to LUDEWIG + TILLMANN Regel- und Sicherheitstechnik GAS – Schweißtechnik KG

Get information about us:

Find on our sides information how to handle gases safely and properly – gases
in their pure state, but predominantly in the form of a mixture.
And now to be really precise: about the art of handling any number of gases, even at different inlet pressures, mixing them in exactly the desired ratio, while maintaining a constant volumetric flow of the mixture at all times.

Get information about us:
Not very modest, you‘ll be thinking, starting with ourselves. But we have no intention of hiding our light under a bushel. On the contrary, we are very proud of our products and services. We have faith in ourselves and so do the many clients who put their faith in us. And not just now, but from the very start, from 1st January, 1971. It all started with industrial gases. Industrial gases – a simple term for a complicated technology, which is used in almost all sectors of industry, both in research and manufacturing. Then as now, the scope of this medium demands a lot of experience, caution and a great sense of responsibility.

LT was established as „Ludewig & Tillmann Regel- und Sicherheitstechnik Gas“ in Dortmund /GERMANY, by the engineers Friedhelm Ludewig and Heinrich Tillmann. Initially, valves and devices for gas systems were designed and manufactured.
Shortly after its establishment in 1971, the company‘s current premises were set up on a 5,100 m2 site in Dortmund /GERMANY, with a factory hall covering 1,300 m2 and a 600 m2 office building. Twenty highly-qualified staff now work here. LT products are exported from here all over the world.
Cost-efficiency, the uncompromising, unconditional acceptance of all safety
specifications, concentration on technologically forward-looking fields of application, ISO-9000 certification and the EU Pressure Equipment Directive form the basis of the current corporate philosophy of LT GASETECHNIK. These are facts that reflect our resolve to meet every requirement of the market, now and in the future.

LT GASETECHNIK is now active in two sectors:
The development and manufacture of valves and devices for almost any kind of gas, concentrating on:
• Safety devices
• Central gas supply systems
• Serial gas mixers
• Electric, Control, Instrumentation and Analysis technology
The development and production of gas supply equipment, such as
• Gas mixing systems and gas mixing plants
• Metering systems
• Control and instrumentation systems
for use in metallurgy, the food industry, welding, hydrogen systems, semiconductor systems and in a variety of very demanding, technologically advanced applications.
We can
• tap gases under control (cylinder manifolds and bundle systems, main pressure
• regulators for automatic or manual operation);
• purify gases (filters);
• regulate gas pressure (HP pressure regulators, dome-loaded pressure regulators,
• control loops);
• safeguard gases against flashback and gas return (flashback arresters,
• decomposition arresters, quick-action shut-off valves);
• analyse gases (sampled gas processing systems, analysers);
• mix gases (gas mixers, mixing systems);
• meter and feed gases (flow meters, ball valves, pneumatic valves, pipe flow
• systems);
• and finally, feed them to the point of use under control (tapping points pressure
• regulators and brackets, quick-action valves).

Our Gas Mixer:
LT gas mixers are used to implement and optimise processes, particularly applications which demand the highest levels of quality and safety.
Hundreds – no, thousands – of LT gas mixers have been in use all over the world for years, in some twenty countries in almost every corner of the globe.

LT gas mixers are available with different outputs and for many uses, e.g. for the production of
• Inert gas for welding (e.g. Ar/CO2)
• Synthetic air for medicine and the chemical industry (e.g. N2/O2)
• Inert gas for the food industry (e.g. N2/CO2)
• Reaction gas for thermal forming (e.g. Ar/O2/H2)
• Forming gas for steelworks and rolling mills and for manufacturing glass (e.g. N2/H2)

LT gas mixers
• are specifically designed for any type of gas, whether inert, combustible, toxic, corrosive, etc;
• withstand almost any pressure, but can also cope with minimal inlet pressures (e.g. 0.6 bar);
• master all relevant temperature ranges (from -196°C to +80°C);
• can be designed to deliver a practically unlimited flow rate, from a few l/min to several thousand Sm3/h;
• withstand extreme installation conditions, even in the open air, defying wind and weather easily;
• are also supplied as an integrated system. Mixers, buffer vessels, analysis and remote control systems are supplied as a self-contained installation.

A summary of the most important characteristics of LT gas mixers:

• Compliance: Technical design is in strict conformity with the most recent European (CE mark) and international standards.

• High reproducibility: Providing that the individual gases used are at the same temperature, static (manually-controlled) LT gas mixers will achieve an absolute degree of accuracy of at least ± 0.5 Vol %, and dynamic (automatically-controlled) mixers with analysis systems will even achieve ± 0.2 Vol% absolute, or better.

• Robust systems, designed for constant use: A long useful life can only be achieved with mature technology. The motto for LT gas mixers is: Mission accomplished. The proof: 20 years of service life and more are frequent.

• Strict quality control: Our control systems start with the selection of components, continue through manufacture and end with dispatch or commissioning on site. Systems are full assembled in the factory and thoroughly tested for fitness for operation (function and tightness) and CE conformity. Everything is fully documented and thus verifiable at any time.

• High-quality fittings: We only use valves and connectors of the highest quality in terms of both material and design (e.g. clamping ring screw connections). Pipework hoses are not used in order to avoid brittleness. Process and pilot lines are made exclusively of high-quality copper tube or stainless steel.

• Design: The design is generous and practical, despite the compact structure of the units.

• Future-oriented, versatile design: The user can easily modify the mixing ratio on site, and also gas withdrawal up to the rated output of each unit. The modular structure even makes easy conversion and extension possible from the outset, e.g. the use of other gases

• Tried and tested interlocking and safety concept: Inadmissible enrichment of dangerous gaseous constituents is precluded at all times by a special interlocking. The pressure regulators in the inlet lines are controlled pneumatically by the carrier gas. If the carrier gas pressure drops, the additive gas will be fed in proportionately. At failure of carrier gas, both gases will be shut off. If the limit of a specified analysis value is exceeded, the supply of the additive gas will be shut off completely.

• High-quality non-return valves: LT gas mixers are fitted with high-quality valves, which reliably prevent even creeping gas return.

• Low-temperature metallic materials: Materials suitable for temperatures down to -196°C are used, e.g. to prevent any potential „overrunning“ by air evaporators.

• Full rated output at all times: LT mixers always perform continuously and safely to their full rated output within the intended working range. Any loss of pressure across the system will not affect it.

• No problem at different inlet pressures (e.g. >10 bar diff.): A constant, reproducible mixing ratio is guaranteed at all times, even if there are major differences between the individual gas line inlet pressures.

• No universal valves: You won‘t find any universal valves in LT gas mixers. All the valves are carefully selected to match precisely the rated output of each unit

• Visual displays: Manometers and flow meters of a generous size provide constant, reliable system performance data, thus facilitating operating checks at any time. The viewing window in the cabinet door facilitates inspection of the displays and makes them easy to read.

• Comprehensive documentation: Our manuals are written in accordance with regulations, but are also practical and easy to understand. They contain plenty of practical hints and tips.

• Ease of use: LT gas mixers are convenient to operate. The design, combined with a self-contained structure, is generous and practical. All the operating features are both clearly laid out and easily accessible.

• Ease of maintenance: The use of high-quality components makes LT gas mixers very low-maintenance.

• Reasonable spare parts stock: The use of uniform components makes a considerable contribution to limiting the stock of spare parts.

• The optional buffer vessel is usually installed in the cabinet, though it can be installed outside instead, if desired. There is no need for connections to the mixer, additional pipework, separate inspection, etc. LT is fully responsible for the guarantee of the complete unit. The buffer vessel is usually made of Stainless steel and is thus designed for temperatures down to -196°C. Even if a Carbon steel buffer vessel is provided, it will be designed for temperatures down to -40°C. The buffer vessel is fitted with a full-size bypass to facilitate its maintenance in continuous operation, guaranteeing that the gas mixer will operate at its full rating without interruption. The buffer vessel is controlled electro-pneumatically.A blow-off pipe facilitates precise adjustment of LT COMPACT gas mixers, even without a connected point of use.

• The optionally integrated analysis system (e. g. LT GasAnalysis or Gas Analysers of other makers) tests the mixture continuously for safety, e.g. for combustible mixtures, and also for quality control, e.g. in the food industry. LT gas mixers are fitted with high-quality Gas Analyzers, designed for constant operation within a temperature range of +5°C to +50°C. The Gas Analyser is placed outside the gas mixer cabinet, but in its vicinity, usually above it, thus minimising the reaction time and facilitating immediate analysis of the gas mixture, all of which ensures a high level of safety, enhanced by an extraordinarily low level of drift of the instrument’s measuring cell. The evaluating unit is already integrated into the analyser and need not be installed and wired separately.

• The mixer is located in a cabinet with a lockable door incorporating an inspection window, to protect it against the effects of the weather. The cabinet is suitable for installation in the open air and is designed for ambient temperatures from -40°C to +60°C. The analyser and the analysis unit are also installed in a separate weatherproof cabinet of the same type, again with a lockable door incorporating an inspection window. Channels for fork-lift trucks make the system movable to suit your requirements.
P.S.:The case of a client who purchased one of our gas mixers (serial no. 4) in 1972 and proceeded to forget all about it has become a company legend. Why? Because the unit did not require readjustment or maintenance in 22 years of operation!

Our clients:
Have you seen our references? World-famous names confirm that we deal with a whole range of reputable clients for our systems, from a wide variety of industries and with widespread demands.
Confident clients who always come to us knowing exactly what they want – and we do not disappoint them. Clients with one new problem after another, challenging our engineers once in a while. Demanding, of course, but also grateful clients, who are not reticent in expressing their gratitude.
And because everything ultimately depends on things being this way, we take all the more care that things stay this way.

Our Competence:
And what, we hear you asking, is so special about LT gas mixers?
The answer is deceptively simple: the skill and experience of our engineers. Their experienced and safe handling of gases and gaseous mixtures, particularly their ability to plan ahead, secure the best solution, avoid risks and yet perform to the highest standards. Their skills, acquired over many years, are expressed in the detailed planning of the systems. Nothing is left to chance. Components are subject to strict selection criteria and even the tried and tested design and operation principle (flow – equal pressure – mixing process), which is the hallmark of LT gas mixers, is tested again and again. Technical innovations are, of course, also integrated, but they must first be examined in detail and thoroughly tested before they can be used in LT gas mixers.
We are happy to advise on any questions regarding handling gases. Where extensive, complex projects are concerned, preferably in the planning phase. If safety considerations or reports are necessary in such cases, we can call on the knowledge and experience of about 100 specialist engineers at our associate companies in the weyer group. Interpreting client specifications which demand bespoke solutions is our bread and butter. We will not be defeated, even by difficult, highly-specific applications. On the contrary, they stimulate us and spur us on. Cases like these have become an LT specialty over the years. This is where we put our strengths to the test. It is precisely these cases which give our systems and our company as a whole the distinctive character of which we are proud.

“I‘m fed up with gas mixers“, you‘ll be thinking. Well, it was important to us to discuss the subject thoroughly, but now we have spent so long talking about ourselves, it‘s high time to let you have a word.
Can we give you any encouragement?
Please tell us about your work and the plans and projects in which you are involved – everything which has anything to do with gas and gaseous mixtures.

We are looking to you contacting us by email (mail@lt-gasetechnik.com) or by phone (+49 231 961070-0).