The load cell design utilises 17-4PH stainless steel for the sensing element and cover in conjunction with a stainless steel IP68 cable gland, submersible polyurethane cable and a double ‘O’ ring sealing system to ensure that the transducer’s integrity is maintained at all times.

The submersible load cells achieved an accuracy of better than 0.5% of rated capacity despite their low height of just 40mm.  It was also fully temperature compensated over the operating range to minimise the effect of the application’s cyclic thermal profile.

The submersible CCG annular load cell, alongside the DDEN in-line submersible load cell, are just two of a number of customised transducer designs from Applied Measurements that are suitable for both permanent and temporary submersion in a variety of medias including water and hydraulic oil.

In addition to low level submersion applications where external pressures range from a few hundred millibar up to 4 or 5 bar typically, we also specialise in the design of load cells for use in applications where much higher pressures in excess of 620bar (9000psi) are present, such as subsea vessels and systems, ROVs & AUVs, oil well tools and pressurised vessels.  The majority of these designs feature a pressure compensation system to nullify the external stresses experienced in these demanding situations and ensure high accuracy measurements.

For further information on the submersible annular load cell, or to discuss the design of a customised sensor for your particular application in detail, please contact our sales engineers by telephone on +44 (0) 1189 817339, or by email info@appmeas.co.uk.

The aim of the investigation was to determine if girth tension affects equine stride characteristics.  The positioning and tightening of the girth strap has traditionally been based on the rider’s preference or own training, in the knowledge that too loose or too tight would be dangerous to both rider and horse.

It is well known that optimum girth tension varies between the size and type of horse, the activity –racing etc and the type of girth. However there is little if any published information on girth tension and how this may affect the locomotion of the horse, that is duration, stride length and speed.

A custom designed S-type tension load cell was used to continuously monitor the tension in the girth during the period under test. The load cell was mounted almost vertically alongside the chest of the horse where unwanted torsional effects on the load cell would be at their minimum, it was fitted to the strap via rod-end bearings and a cam buckle so that minute changes to the girth tension could be made.

This was connected to a T24 telemetry module, located in a pouch on top of the saddle which transmitted the force measurement reading wirelessly to a telemetry base station located nearby.  This was plugged into a laptop that served to both power it and log the tension reading.

Extensive testing on 19 horses at 4 girth tension settings were conducted resulting in definite conclusions on the effect of girth tension on the speed, stride length, stride duration and walk.

This application is typical of the way in which Applied Measurements’ custom force sensors are helping all sectors of research and development as well as solving the needs of industrial production.

For more information on our custom force sensors capabilities and other load measurement products, please contact us on 0118 9817339 or email info@appmeas.co.uk

This weighing approach is cost effective and quick to install, causes a minimum of production down time and is ideal as a retrofitted system. The BOSS bolt-on sensor is a well-proven robust product consisting of a strain-gauged element encased in a protective housing.  It is simply bolted to a structural member of the silo and deflects under the changing weight conditions, to give a varying electrical output relative to the load.

Bob Davies, general manager at Applied Measurements comments “with more than 25 years experience of bolt-on sensors, we assess the suitability of this method of measurement for each individual enquiry, including an on-site survey if required. This ensures the feasibility of a successful installation at the outset and we will commit to the accuracy likely to be achievable”.  The very first consideration is the available stress for the sensor to measure and this is broadly dependent on the load applied and the design of the supporting structure it is mounted on.

Bolt-on systems are more than adequate for the majority of vessel weighing or level monitoring systems, where accuracy in the order of 1% – 2% is acceptable.  We bolt the standard transducers to a suitable supporting member such as a leg, girder, channel or pipe.  However in some applications custom profiled mounting blocks may be required to suit the profile of the supporting steelwork.

For a system to be viable the load to be measured should be between 3000psi and 10,000psi.  The accuracy achieved depends on a number of factors, but most significantly the amount of available strain to be measured.

Each BOSS sensor has an average sensitivity of 1.7mV/V for 10,000PSI.

As a general rule, sensors mounted internally will give the best results. With external systems there will often be a margin of error due to zero shift, which is a result of differential expansion due to solar radiation but even this can be nullified to an extent.  The accuracy achieved will be very dependent on the positioning of the sensor on the steelwork.

Accuracy Bands

• 3,000 – 5,000     PSI     gives +/- 2 to 3% or better
• 5,000 – 7,500     PSI     gives +/- 1 to 2% or better
• 7,500 – 10,000   PSI     gives +/- 1%

Typical Application

A 220T cement silo on a 6-leg pipe section frame, giving 6000PSI total available signal.  Our customer required best accuracy for batching to supply ships and road tankers. As the available signal was good but not exceptional, we suggested 2x BOSS bolt-on sensors per leg to minimise errors and maximise accuracy.  The result is that the customer can batch to ships +/- 1Tonne in 100T and +/-0.5Tonne in 30T.  To minimise the effect of temperature, each Bolt-on sensor is fully insulated after installation

Suitable instrumentation to accompany the bolt-on sensors includes: mains or battery-operated digital displays, local amplifiers allowing the signals to be monitored in a control room or a telemetry system for wireless monitoring via a remote hand-held receiver or a control room PC system.

For more information on the range of BOSS sensors please visit our bolt-on load cells page, or call us on 0118 981 7339 or email: info@appmeas.co.uk

Friction stir welding is now widely used in the aerospace, automotive, rail and ship building industries.

Unlike other friction stir welders, the LowStir friction stir welding system includes a unit that attaches to most standard milling machines via an ISO taper, making it an affordable option to smaller enterprises.  It is supplied with software to calibrate the system, monitor the welding process and log welding parameters for later analysis.

The current LowStir base system comprises the necessary hardware and software to convert a suitable milling machine to a LowStir stir-welding system including an ISO taper (or equivalent) to fit it to the milling machine.  Since this depends on the particular machine, the size and type of taper must be specified when requesting a quotation (as costs of tapers can vary).

Benefits of Friction Stir Welding

• Improved weld properties (e.g. strength, fatigue) compared to arc welding or riveting.  Joint efficiencies of 75-96% have been reported depending on materials.
• Because it is a solid phase process (where the materials are joined without melting) no shielding gases or filler materials are required. Furthermore, there is almost complete elimination of weld distortion and solidification defects.
• Operators do not need special qualifications or certification.
• There’s no arc welding, gas emissions or weld spatter involved.
• Vastly reduced preparation and reworking time reduces costs, time and labour requirements.
• Low power consumption; The only energy required is to rotate the tool and apply force to it to create the frictional heat.  Without the large current requirements of arc welding, energy consumption can be reduced by 80% plus.

The LowStir System

Specifically, the basic components of the system are as follows:

1) LowStir Mk.2 sensor head unit including tool holder and heat shield disc.  This is supplied already bolted together as a complete system including the ISO taper, ready for installation in the milling machine head.

The LowStir unit is capable of measuring:

• Down force (Fz) to 50kN
• Lateral force (Fxy) to 25kN
• Torque (Mz) to 100Nm
• Temperature of the welding tool via an internal thermistor

The unit will run at rotation speeds of up to 3000rpm and log data at software selectable rates from 1Hz to 100 Hz.

2) Inbuilt battery.  When fully charged, the LowStir unit’s inbuilt battery has a battery life of approximately 10 hours.  The unit is supplied with a battery charger, which can recharge this battery from the mains.  The charger automatically deactivates when the charge is full, so the unit can be safely left to recharge overnight.

3) Jack plug switch.  The unit is also supplied with a jack plug switch which can be inserted to completely disable the unit and store any remaining charge.

4) Set of tool assemblies.  A typical assembly comprises a low wear shank and a replaceable tool (probe).  If you order one tool type there will be one shank and ten probes supplied.  If you order two different types of tool then there will be two shanks (one for each material to be welded) and five probes supplied for each of the two shanks.

5) Taper.  As mentioned above, the system includes an ISO taper or equivalent specific to the milling machine to which the LowStir is to be attached.  The size and type of taper required must be detailed in advance, and ordering the incorrect taper will make it impossible to fit the LowStir unit.

6) Software for monitoring and recording various parameters of the weld.  Note that the software is supplied uninstalled and uncalibrated.  We strongly recommend the optional laptop package, as this is supplied with the software and Bluetooth connection fully set-up and calibrated.  See Optional Extras below for more details.

Optional Extras

The following are optional extras that can be supplied at extra cost.  Please specify any extras required when requesting a quotation.

1) Internal temperature probe.  The system can be supplied with an internal probe which is used to monitor the temperature of the weld pool via a probe fitted to the inside of the welding tool holder.

2) Laptop. The software can be provided ready installed on a laptop computer.  In addition, the software will be calibrated for the specific LowStir unit, and the Bluetooth connections established between the laptop and the unit.  It is strongly recommended that this option is taken, as it means that the system is ‘plug and play’ and removes the need to calibrate the system on-site.

Licence

Please Note: Currently you will need a licence from TWI to carry out friction stir welding.  This applies to ALL forms of friction stir welding, including using LowStir.  Please contact TWI or David Johnson at Applied Measurements Ltd for more information.

“Despite the current economic downturn, we have grown our sales revenues by more than 30 per cent over the last three years,” says Peter Lewis, Managing Director at Applied Measurements Limited. “A major part of this growth is coming from our custom design service for our products, which include load cells, torque sensors, displacement sensors and pressure transducers. We are supplying one-off designs, pre-production prototypes, high volume specials, direct competitor equivalents, as well as modifying or strain gauging existing components.”

According to Lewis, many of Applied Measurements’ global customers now request custom designs on as fast a lead time as possible. “Rather than trying to make existing, standard catalogue sensors ‘fit’ their application, customers now seem to want custom solutions delivered in as short a time frame as possible. After all, there seems little point in offering a custom design service for your sensor if the lead time doubles as a result. Customers simply won’t wait that long. In most cases, we can deliver a custom solution – including concept design, engineering, production and calibration if required – in just six to eight weeks from customer order.”

In a tough economic climate, says Lewis, Applied Measurements has recognised that this ability to meet a customer’s exact design requirements on a competitive lead time, has given the company a clear edge on its competitors.

”Our design service not only includes the ability to design new custom sensors,” says Lewis, “but also includes manufacturing direct equivalents to existing competitor products, as well as retrofit versions that the competitor may have ceased to produce. It can also include the bonding of strain gauges to metal structures or housings provided by the customer and then completing these into a finished, certified and tested product.”

Machine builders and systems integrators often need to upgrade a machine for the end user, to include new electronics or instrumentation, from older mechanical gauges or dials. As Lewis states: “In this age of accountability, it is important to have sensors that are connected to the appropriate instrumentation, including PCs that log and record the measurement data, providing traceability for the end user. In these types of applications, there are usually physical restrictions that also need to be overcome, as the customer is likely to want minimal disruption to the original machine. This is where our ability to fit in with the existing design is a big advantage to the customer. Our combination of mechanical and electronics design capability also helps here.”

Many machine builders need their systems to measure in more than one axis at a time. For this, Applied can design two or three-axis force sensors, with a variation on this when customers want a sensor to combine two measurements, such as force and torque, or force and acceleration.

The aim of the custom design service is to provide customers with a solution that exactly fits their measurement requirements under the constraints of cost, size, environmental conditions, general performance specification and availability. As Lewis puts it: “An incorrectly chosen transducer to fulfill a particular measurement application costs considerable time and money if it is eventually discovered that the data being collected is meaningless, or that the transducer is performing incorrectly due to overloading or poor installation.”

“Our experienced application engineers will talk through the measurement requirements with the customer in order to determine the most appropriate solution. This typically includes discussions on the measurement range required; dynamic transient effects; space restrictions; accuracy levels; and whether there are any unusual environmental conditions to consider.”

For more information on Applied Measurements’ custom engineered solutions please contact our sales department on 0118 981 7339 or send an e-mail to info@appmeas.co.uk.

With a small, quick and cost effective re-design we changed the construction to Stainless Steel with two halves locking together with a seal.  Internally it was further protected by back-filling with an inert waterproof gel.  The electrical termination is a tough IP68 multicore cable that is connected through an IP68 cable gland, to complete fully submersible sealing.

The new underwater load cell has been designated as the DDEN series.

By modifying an existing product we were able to keep the cost and delivery time down to suit our customers needs, whilst displaying our capability to modify or design a product quickly and efficiently.

Click here to view the DDEN Submersible Load Cell product page.

During development a bespoke calibration system was also built to ensure that each strain sensing beam was accurately positioned and loaded for consistent quality.

Following the successful acceptance trials and approval by our customer, the strain sensing beam has been put into full production, which is expected to exceed 2000 pieces per year.

This is a typical example of our design, development and manufacturing capabilities in the field of bonded strain gauge technology.

Applied Measurements Ltd were supplied with a standard link from the chain, this was modified to enable strain gauges to be bonded to the structure, creating a strain-gauged chain link.  The transformation of the link into a load cell was completed by terminating with a four core screened cable, environmental protective coatings and calibration.

The strain-gauged chain link was then installed in the standard process chain and fitted with a portable data logger, this enabled the special link to map the forces around the system allowing adjustments to be made where required to ensure even tension, reducing chain wear and system stoppages.

The sensors are designed to be attached directly to steel structures and are capable of detecting tensile, compressive and bending stresses.

Utilizing the latest strain gauge technology, each sensor is manufactured from specifically selected high grade alloy steel with thermal coefficients of expansion matched to structural steel.  Unlike some competitive units each sensor is temperature cycled and compensated to minimize the effects of temperature variation.

For installation, each unit is supplied with a template to which the two threaded mounting blocks are attached using high tensile bolts.  The mounting blocks are welded in position and the bolt-on sensor then attached in place of the template.

The sensors are fully encapsulated to ensure complete protection from all but the very harshest of environments.

Click here to visit our main Bolt-On Sensing page

Applied Measurements Ltd designed and manufactured a custom load cell based on the CCG load cell concept, but to exactly fit the existing mechanical dimensions.  It had to be annular to allow the tensioning system to fit through the centre and to be extremely low in height to replace an existing washer.

To complete the system each load cell was supplied calibrated with a digital indicator containing 4 changeover relays.  Each system operated from a 240Vac supply, giving the system operators a visual reference of the tension in the system, plus the relays controlled an early warning alarm system allowing preventative maintenance.