COVID-19 Ventilation

As defined by the Health & Safety Executive (HSE) website, the law states that “employers must make sure there’s an adequate supply of fresh air (ventilation) in enclosed areas of the workplace”. Following the COVID-19 pandemic, this of course is now even more important.  Adequate ventilation reduces how much virus is in the air. It helps reduce the risk from “aerosol” transmission.  Aerosol transmission can happen when someone breathes in small particles in the air (aerosols) after a person with the virus has been in the same enclosed area.

The risk from aerosols is greater in areas that are poorly ventilated.

You can do this by using:

 

(The above links will take you directly to the HSE website).

 

From either method above though, it is important to quantify the performance of your ventilation, be that natural or mechanical.  An HSE recognised method is via CO2 detectors.  Fluidic have a long history of supplying Vaisala CO2 detectors such as the GMW90 Series.  This wall mountable detector also has options for RH&T monitoring to ensure your office is operating at the most comfortable and efficient conditions.  A local display is accompanied by red/amber/green warning LEDs for quick visualisation of office conditions.  A 4-20mA signal can also be brought back and incorporated into your office BMS system where appropriate.

 

Video by the HSE on Ventilation and the use of CO2 detectors

 

Along with the links above, see HERE for more information directly from the HSE website.

 

Within our own Glasgow office, we are currently using a GMW86P sensor, connected to our Hanwell EMS datalogging system.  This gives real-time logging of current CO2 levels, with email alarm alerts should CO2 levels rise beyond an internally set threshold.  This system gives 24/7 monitoring, so we can also measure CO2 levels when the office is unmanned, useful as a reference level vs a full office.  A remote log in demonstration is available if you were interested in this system – please call the Glasgow office on 0141 641 5920 to arrange.

 

Some photos of our setup can be seen below:

 

Fluidic CO2 office monitoring via EMS

The above shows the Vaisala GMW86P which provides a continuous  4-20mA output.  The 4-20mA is collected by a Hanwell RL4809 and information updated to our Hanwell EMS system every 15 mins.  Incidentally, to the left of the RL4809, note we have an RL4114 RH&T transmitter to monitor the general comfort levels for our team.  This is a 3.6V AA battery powered device, with battery life expected <2years in normal service.  Fluidic offer annual calibrations on most Hanwell transmitters and would generally change the battery as part of this.

 

Office CO2 levels 13/12/21

Above shows a screenshot of yesterday (noting this post was created 14/12/21).  We have a high level alarm at 1,000ppm in line with ASHRAE typical standards and a High High alarm at 1300ppm – set as a failsafe for our own peace of mind. Although our office is showing CO2 levels well within these levels, it is interesting to note that there is a clear rise in CO2 levels as the team start to come in the office at about 8.30am, dropping again just after 5pm.

 

For help with any ventilation measurement application, please call either office – Glasgow (0141 641 5920) or Warrington (01925 572401).

 

Job Opening: Internal Sales Engineer, Glasgow

Internal Sales Engineer, Glasgow

Fluidic are a progressive, instrumentation distributor with 2 UK locations. We are looking to strengthen our Glasgow office with an Internal Sales Engineer.  Key responsibilities of the post will include:

 

 

Applicants will have a technical background.  A background with instrumentation or control being a distinct benefit but not necessarily a deal breaker – applicants with a strong work ethic and “can do” attitude would be looked on more favourably.

 

Due to the nature of the role a clear, polite telephone manner and literacy with Microsoft Office (Word, Excel and Outlook) are imperative.  The company also employ a CRM system (Act!) and Sage Accounts ordering system.  Training on both systems would be provided.

 

The job is envisaged as an internal role working typical office hours.  Very occasional travel may be required, in some cases internationally for supplier training etc.

 

An industry competitive salary and twice annual companywide performance bonus will be offered to the successful candidate in line with experience.

 

Instrumentation and control is an exciting and continually developing market place. Product training will be provided in an ongoing basis; however, it is of course understood that an emphasis will be given towards training in the first few months of employment.

 

To apply for the position or for any more details you may wish to discuss, please email: carolina.delacruz@fluidic-ltd.co.uk 

 

Junior Support Technician (Glasgow)

Fluidic are pleased to welcome Calum Park to our Glasgow office in the role of Junior Support Technician.  Calum starts with us through a government “Kickstart scheme” to get young people into employment.  Calum holds a First Class Masters degree in Aero-Mechanical Engineering, covering modules in Heat and Flow, Control Systems Design, and Electrical Power Systems.  Over the next 6 months Calum will shadow our internal sales and service teams to help with quotes, calibrations and some instrumentation repair work.

Thermocouples: Cold Junction Compensation

Thermocouples are among the most popular types of temperature sensor types in industrial applications. Their biggest advantage of a thermocouple is that it can measure very high temperatures even much higher than RTDs. However, thermocouples do not give us an absolute temperature reading; they only give us a relative measurement. This application note discusses the basic operation of a thermocouple, which includes the definition and function of a reference (cold) junction.

 

How does a thermocouple work?

These sensors consist of two wires of dissimilar metals joined together at a single point or junction. As a result, the union between these two metals generates a voltage that is a function of temperature. Thermocouples operate on this principle called “Seebeck Effect”. While almost any pair of metals can be used to create a thermocouple, only a certain number of them are used because they produce predictable voltages and wide temperature gradients.

 

Thermocouple

 

To know what the temperature is at the hot end, we will need to identify the voltage produced and the temperature at the other (cold) end. Unfortunately, it is not possible to connect a voltmeter to the thermocouple to measure this voltage because the multimeter connection is typically a different material than the thermocouple material. Therefore, we will be creating two new thermocouples in the multimeter connections. A technique known as Cold Junction Compensation was developed to solve this problem.

 

Cold Junction Compensation

Initially, the cold end was put in an ice bath; something that any laboratory could reproduce. Next, thermocouple voltage tables were developed based upon the cold junction end being in an ice bath. The voltage was recorded and looked up in the tables referenced to the ice bath (0°C) and the hot end temperature was derived.

Thermocouple with ice bath cold junction compensation

Today, it is impractical to use the ice bath in industrial uses. There are two commonly used approaches:

Thermocouple with induced voltage cold junction compensation

 

Then, this allows electronics to use the established thermoelectric voltage tables (or polynomials) to determine the temperature at the hot end. This approach makes two approximation errors, one for estimating the cold junction temperature, and one for approximating the effects on junction potential.

 

Thermocouple

 

This approach uses one less estimate, but it still depends on accurate measurements of the cold junction temperature.

 

Thermocouples are differential temperature-measurement devices. When working with them, a reference point must be established. The main selection criteria for the appropriate cold-junction compensation device are accuracy, cost, linearity, and temperature range. Some platinum RTDs offer the best accuracy, but at higher cost. Thermistors are inexpensive and operate over a wide temperature range, but their lack of linearity can be problematic. Silicon temperature-sensing ICs operate over a narrow temperature range but offer reasonable accuracy, linearity, and low cost, thus making them a suitable choice for many thermocouple cold-junction compensation applications.

Via our partnership H&B Sensors, Fluidic can supply complete temperature instrumentation assemblies. Please take a look at our thermocouple range and accessories such as connection headsthermowells and transmitters. Our team is technically trained to help with any instrument selection.

For further information regarding thermocouple charts please check our post here.

Differential Pressure

One of the most common measurements taken by instrumentation is pressure, particularly differential pressure. So, what is differential pressure and how is it measured?

 

What is Differential Pressure (DP)?

Differential pressure is, quite simply, the difference in pressure measured between two points.  Filtration is a common application where pressure drop across a filter (i.e. the pressure difference between upstream and downstream of the filter) is indicative of filter condition.  A blocked filter, or one nearing saturation, will cause a large pressure drop and require the associated pump/fan to work much harder.  This is easily monitored by DP, allowing an economical filter change maintenance routine.  Additionally, it can be noted that a very low differential pressure could identify a burst filter.  (The Dwyer Photohelic A3000 Switchgauge and Dwyer Photohelic 3000MR Switchgauge both include a gauge measurement display and adjustable high and low DP switch outputs for such practice).

Other common applications include cleanroom monitoring (to ensure rooms are maintained at positive or vacuum pressure as required, often in a cascade environment).  In hydrostatic level monitoring, we often use differential pressure to compensate for any inherent pressure in the tank.  See the Honeywell STF800 SMARTLINE Hydrostatic Level Transmitters for more details of this application.

 

Particularly in air or gas applications, differential pressure can be very low – often measured in Pascals.  One Pascal (1Pa) is the equivalent of 1/100,000 bar.  It is essential to ensure that the correct type of differential pressure instrument is selected per application.

 

How do we select the correct differential pressure instrument?

This will depend on a number of factors, but the measurement principle remains similar regardless.

As mentioned earlier, differential pressure is measured between two points. This may be two pressurised areas or one pressurised area with the other open to atmosphere. The measurement will be taken through the instrument, be that a gauge, switch or transmitter.
In all DP instruments, each pressure input will feed either side of a measurement diaphragm. The diaphragm will flex in the direction of +ve differential pressure.  The extent of this positive deflection will drive the measurement sensor (often a piezoelectric sensor, or in the case of the Dwyer Magnehelic Differential Pressure Gauge via a magnetically driven helix), to a conditioned output, trip or gauge display.

It can be seen that diaphragm material selection is extremely important.  When selecting the type of instrument required it is essential to know the ballpark range of pressure the instrument will be dealing with, as well as the medium that it will encounter. Diaphragms come in various material types to handle the varying ranges of these requirements.  The commonly specified 316SS diaphragm will not typically suit small, pascal measurements such as cleanroom or air HEPA filter monitoring applications.  Our range of transmitters from Micatrone along with Dwyer’s previously mentioned Magnehelic and Photohelic options utilise large rubber diaphragms which are responsive to small pressure changes.  Dwyer have recently released a new 0-30Pa range within the Magnehelic allowing higher accuracy than ever before in such applications.

 

Dwyer Magnehelic Product Overview Video

 

DP vs two separate pressure measurements?…

In theory, two separate pressure transmitters could be used to generate a DP measurement within the control system itself.  For example, a liquid line may be running at 3bar.  A filter with a normal operating pressure drop of 100mbar could be considered for change at, e.g. 200mbar (manufacturers will normally recommend specific values).  It could be argued that a 0-5bar transmitter/gauge may be fitted either side of the filter.  In clean conditions upstream will measure 3bar, downstream 2.9bar, giving a differential of expected 100mbar.  HOWEVER, give consideration to the uncertainty of measurement of each device, which is typically taken as a percentage of full scale.  For a +/- 1%fs instrument, a 0-5barg pressure transmitter will have an uncertainty of 50mbar.  Doubling this (as there are two transmitters), the total DP measurement reading could be argued as 100mbar +/- 100mbar!!  Using a differential pressure transmitter of range e.g. 0-500mbar DP and the same +/-1%fs, the same measurement would be 100mbar +/- 3mbar – a much more reasonable working tolerance.

 

Honeywell STD800 Knockup

The very crude “knock up” schematic above shows how a Honeywell DP transmitter may be fitted across a liquid filter bank for DP measurement.

 

Many manufacturers offer “electronic DP” using two gauge pressure transmitters.  There can be a lot of benefits in this design, but always give consideration to each specific application and the pressures etc under scrutiny.  Fluidic have engineers on hand to help with instrument selection.

 

Please call either office for more information (Glasgow 0141 641 5920, Warrington 01925 572401)

Latest Response to COVID-19 outbreak

Fluidic are in full support of the most recent announcement made by the Prime Minister on the evening of 23/3/20.  Our sales and accounts teams are all working from home and remain fully contactable via the usual office and email numbers.  In support of essential industries (including power generation, hospitals, pharmaceutical, food production etc) only the very minimal staff required to complete essential orders and deliveries will attend our workplaces.  This includes calibration, service and dispatch.  Any team member attending the workplace (which is 2 maximum each site) will maintain the government specified distancing and will only be there as and when absolutely necessary.

 

In response to the delays that initially came through following the epidemic, we recently reviewed and increased our stock levels to support ongoing demand.  Particularly in the case of products like the Dwyer Magnehelic and Micatrone MF-PFA both of these instruments are used in isolation pressurisation monitoring and were included in our recent stock boost.  We have already seen orders for isolation booth monitoring this week.  Wherever possible we are keen to play whatever small part we can in helping the essential services continue.  (Our instrument supply to essential industry is far from limited to these instruments, merely an example that are currently in stock).

 

For any sales enquiries (for any application), or an accounts enquiry please contact our team working from home via the normal email and telephone numbers.  Forthcoming months are going to be tough on everyone.  We all must work together to maintain a strong economy for the times ahead.  You can be sure that everyone at Fluidic will play our part.

 

Most importantly, we wish all of our customers and partners a safe and healthy time throughout this ordeal.

 

 

Contamination Expo, NEC Sep2019

Fluidic were pleased to join our partner, Status Instruments at last week’s Contamination Expo at the NEC, Birmingham.  Our Dave Farman joined Status’ Lizzie and Lawrence for an interesting event, focusing on the Waste Water sector.  Datasheets for our range of Status products can be found HERE.

 

One product offering particular excitement, was Status’s brand new SEM320 Temperature Transmitter with in built head and display.  This transmitter includes flagship electronics, including HART output, and was exclusively released at the show.  Photo of the demo kit shown top right in the photo below.

 

Status Instruments

Glasgow Recruitment

Fluidic are hiring

Fluidic are a progressive, instrumentation distributor with 2 UK locations. We are looking to strengthen our Glasgow office with an Internal Sales Engineer.  Key responsibilities of the post will include:

 

 

Applicants will have a technical background.  A background with instrumentation or control being a distinct benefit but not necessarily a deal breaker – applicants with a strong work ethic and “can do” attitude would be looked on more favourably.

 

Due to the nature of the role a clear, polite telephone manner and literacy with Microsoft Office (Word, Excel and Outlook) are imperative.  The company also employ a CRM system (Act!) and Sage Accounts ordering system.  Training on both systems would be provided.

 

The job is envisaged as an internal role working typical office hours.  Very occasional travel may be required, in some cases internationally for supplier training etc.

 

An industry competitive salary and twice annual companywide performance bonus will be offered to the successful candidate in line with experience.

 

Instrumentation and control is an exciting and continually developing market place. Product training will be provided in an ongoing basis; however, it is of course understood that an emphasis will be given towards training in the first few months of employment.

 

To apply for the position or for any more details you may wish to discuss, please email: steven.biggs@fluidic-ltd.co.uk

 

Filtration Monitoring

Filter monitoring in HVAC systems

Filter monitoring is an important part of maintaining an HVAC system. Air filters are used in HVAC systems to capture and prevent particles from entering the conditioned air stream. Air filters are available in a wide range of configurations and sizes, and can be found in a variety of locations depending on application.

 

Mechanical equipment rooms, workshops and warehouses typically have a pre-filter located at the input of the air handler prior to the junction of the outdoor and return air ducts. A secondary filter may also be found after the fan but prior to the main trunk of the HVAC system. The main purpose of this filtration system is to  remove larger particles and to protect the heating and cooling coils from dirt build-up.

Laboratories, cleanrooms, hospitals, pharmaceutical R & D areas and similar facilities may have two different types of pre-filters at the air handler input, and also at the final filter stage after the air handler.

 

Applications requiring contaminant-free air such as pharmaceutical labs, biological research labs, hospital operating and intensive care rooms, isolation areas and some high tech assembly areas require the use of HEPA (High Efficiency Particulate Arresting) filters. These filters trap 99.97% of all particles. The HEPA filter is composed of randomly positioned micro glass fibers woven into a thick bed of material that may be several inches thick. There is no direct or straight line of flow through the filter, but a random, twisted path that forces multiple particle impacts with fibers, greatly increasing the chance of being captured.

 

During use, a filter will become loaded with particles. A filter will become more and more effective as this loading takes place, up until a certain point. Once this certain point is reached the filter can start to impede air flow and increase demand on the air moving equipment. This can damage and shorten the life of equipment.

 

Optimizing filter usage means careful monitoring of the filter’s performance. A cost effective way to do this is by measuring the pressure drop across the filter. By selecting an appropriate range of Dwyer Magnehlelic differential  pressure gauge (maximum permissible pressure drop across filter should be included in datasheet for filter), we can monitor this pressure.

 

With the High and Low sides of the Magnehelic differential pressure gauge connected via static pressure ports either side of the filter, and with red/green zoning applied to the dial face to indicate maximum allowable pressure drop , engineers can see at a glance if the filter is performing as it should.

 

magnehelic zonedMagnehelic Filter monitoring

 

This simple, but effective means of filter monitoring helps protect the air handling equipment and also helps protect the health of occupants in the building by making sure the filters are working effectively and are changed as and when required.

 

Fluidic Ltd are the official Scottish distributor for Dwyer Instruments. We also stock all of the associated items required for installation such as tubing and static pressure ports. Fluidic also offer a dial zoning service as well as calibration.

 

For further information on this and more HVAC products and services that Fluidic can supply, please see attached brochure. Download

 

If you need assistance please contact michael.campbell@fluidic-ltd.co.uk or on 0141 641 5920.

 

 

Air Balancing

Fluidic Ltd, as distributors for Dwyer Instruments, have been actively promoting Dwyer’s new Smart Air Hood (SAH). The SAH is a new design of Air balancing Hood, featuring unique Quad Core Technology. This design, coupled with clever, in-built calibration for numerous diffuser styles, means more accurate and reliable readings can be taken from ventilation registers when commissioning and balancing an air conditioning system.

The added advantage of Dwyer’s PredictAir software, which guides the user as to which damper to adjust, and how much to adjust to achieve target air flows, allows for a system to be balanced more efficiently and accurately than before.

 

Fluidic’s Michael Campbell recently had an article published in the Scottish Society for Contamination Control (S2C2) magazine, the Cleanroom Monitor. The attached article (button below) highlights the issues presented by conventional Air Hoods, and how Dwyer’s SAH overcomes these issues.

Dwyer SAH Smart Air Hood

 

 

 

S2C2 Article on Air Balancing Hood Technology

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