M+W Instruments GmbH, an operational business unit of Bronkhorst®, specialises in the production of direct measurement, otherwise known as through-flow, thermal mass flow meters and controllers for virtually every type of gas.

Based on many years of experience and dedication to continuous research and development, their sole focus is the production of high quality instrumentation based upon the CTA (Constant Temperature Anemometry) principle with flow rates ranging between 0.1…6000 ln/min Air equivalent.

With dedicated personnel for application engineering, service and support, Bronkhorst UK Ltd forms an integral part of the global network of local sales and service offices providing rapid response to customer enquiries, needs and wants. The Company Ethos is very much “can do”, an approach that is cherished by its many customers.  

The Challenge: Within the medical arena there is increased pressure on both budgets and financial accountability, with a significant trend for the sector to look again at how resources are used and where savings can be made.

One of the largest expenditures in most hospitals is the cost of either purchasing or producing the various medical gases needed such as Medical Air, Nitrogen, Oxygen and Nitrous Oxide. Often the usage and consumption of these gases is neither monitored nor measured or, whenever it is done, it is often a crude estimation, inaccurate and recorded only by pen and paper.

Most hospitals rely on the rate at which the cylinders (in which the gas is supplied) empty to determine the amount and rate of gas used.  There are of course many issues associated with this method, such as-:

  • The amount of gas in a particular sized cylinder can vary greatly, even when directly delivered by the gas supplier
  • Total gas consumption and peak times of consumption cannot be accurately determined
  • Leaks can go undetected
  • Specific point of use consumption is impossible to determine

This makes it very difficult to manage costs overall and to assign invoicing costs to individual departments and sections

A Case-Study Answer: A company based in South Wales specialising in the design, installation and maintenance of gas systems was asked to install the medical gas network in a new hospital. An approach was made to Bronkhorst UK Ltd for the supply of gas meters which could then be communication-linked to the building maintenance system.

Bronkhorst offered the M+W MASS-STREAMTM D-6360 & D-6370 instruments with integrated multi-functional displays to fulfil both the accuracy and reliability requirements . As a result of their through-flow measurement CTA technology the instruments offered the additional benefits of no risk of clogging, no wear as there are no moving parts, minimal obstruction to the flow of the gas and hence ultra-low pressure drop, all based upon the fact that the instrument body is essentially a straight length of tube.

In addition to the local integrated displays the instruments also featured both 4…20 mA and RS232 output signals ensuring integration with the Building Management System (BMS) for real time continuous data logging and remote alarming should the gas supply enter low- or high-flow status for any given event. As a double failsafe the instrument offers both on-board flow totalization and further hi/lo alarms.

The installation of M+W Instruments for this hospital application provided the following benefits to the client:

On primary networks:

  • Separated invoicing for hospital/clinic/laboratory departments sharing the same source of medical gas
  • Monitoring and acquisition of consumption data
  • Leak detection within gas line, safety vent and medical gas source

On secondary networks:

  • Independent gas consumption invoicing between the health institution departments
  • Over-consumption detection
  • Monitoring and acquisition of consumption data
  • Leak detection within gas line

Footnote regarding bulk delivery applications: subsequent installations across Europe have followed the trend of increased accountability by installing an M+W Instruments flow meter for the incoming bulk delivery, obtaining a totalized flow reading and cross matching this to the bulk invoice. This could be useful in the event of inadvertent errors or typos when a bulk delivery invoice is being raised.

For more information on the M+W MASS-STREAMTM instrument please contact us;

Bronkhorst UK Ltd, Email: sales@bronkhorst.co.uk, T: 01223 833222