As part of our feature series on safe machine design, Euchner’s Mark Staples answers some questions on the ISO 14119:2013 machinery safety standard and the procedures for the selection of a suitable interlocking or guard locking device.

What does the standard contain?

The standard describes the selection and usage of interlocking devices with/without guard locking on safety doors, safety covers and other movable safety guards. 

The term interlocking devices refers to safety switches fitted to safety doors that ensure machines/systems safely shut down on opening the door. Interlocking devices with guard locking (guard locking devices) only enable access once the risk of injury is eliminated (e.g. the hazard due to over-traveling machine movements, or machine rundown time due to inertia of moving parts, which could be something as simple as a rotating cutting blade).

The standard’s application, like all safety-related standards of this type, gives machine designers an assurance that the requirements of the Machinery directive are met.

Can it be used to obtain UKCA or CE marking?

To assign UKCA or CE marking to a machine/system, the law as applicable to machinery permits various possibilities, one of which is the use of harmonised standards. If all relevant standards are applied, ‘Presumption of Conformity’ can be assumed. 

One harmonised type B standard is ISO 14119, which is applicable independent of the machine type for the usage of safety switches on safety doors. Machine builders may find it difficult to defend themselves if applicable standards have not been followed and accidents occurred because of this.

What are an interlocking device’s component parts?

The standard defines the term “interlocking guard”, which includes the movable safety guard and the interlocking device. This generally has two parts, the actuator and position switch.

What are the guard locking principles?

ISO 14119 contains four principles of operation for guard locking devices:

1. Spring applied – Power-ON released

This is a closed-circuit current principle in relation to the function of guard locking. It means that guard locking devices are moved to the “locked” position by a spring on the removal of the power. Switching on the power opens the guard locking device.

2. Power-ON applied – Spring released

This principle operates in the opposite manner and is referred to as “electrical guard locking”. It’s an open-circuit current principle.

3. Power-ON applied – Power-ON released 

This is a principle that doesn’t change position on the removal of power. It’s also called the bistable principle. Power must be applied to change it to the other state. As the removal of power doesn’t change the position of the guard locking device, it’s considered a closed-circuit current principle.

4. Power-ON applied – Power-OFF released 

This corresponds to an open-circuit current principle as the guard locking device opens on the removal of the power. Typically used for electromagnets, e.g. on the CEM.

Which principle must be selected?

It’s possible to select from these options for the operation of the guard locking. Two of these are closed-circuit current principles where the guard locking device is closed (locked) in the event of a power failure. A guard locking device for personnel protection must use one of these two principles.

The standard permits a minor exception from this selection only if it can be shown that a closed-circuit current principle is an unsuitable method. The evidence for this will be very difficult to find. Often an open-circuit current principle is chosen for the access to the machine in the event of a power failure. However, this aspect can also be ensured using a closed-circuit current principle guard lock with an emergency release mechanism.

For process protection designers are free to decide which type of guard locking is selected as it doesn’t represent a safety function. The only requirement is that on guard locking devices for process protection, the safety of the interlocking device must not be degraded.

How must a guard locking device be controlled and how is the PL of the circuit determined?

The greatest change in ISO 14119 compared to its predecessor is the requirement to consider the control of guard locking as a safety function. This doesn’t mean that a guard locking device must always be controlled with dual channels with immediate effect, only that a risk analysis must be undertaken to determine the necessary PL. 

Guard locking devices like Euchner’s MGB function differently. These devices have a permanent power supply and the control of the guard locking is undertaken via inputs. Therefore, guard locking is not fully de-energised even on shutting down the two inputs. On these devices, the electronics contribute to the probability of failure of the control chain and a block must be added to the PL calculations.

Is the series connection of electromechanical guard locking devices safe?

Series circuits can be used without problems up to category 1. The situation becomes difficult if diagnostics on the individual safety switch is necessary. The problem here is that with a series connection, faults are masked by other safety switches. Unfortunately, this aspect is often overlooked and can lead to even relatively new equipment having guarding faults going undetected.

With many of its solutions designed in partnership with some of the world’s leading off-highway vehicle OEMs, Curtiss-Wright Industrial Division will use its stand at CONEXPO-CON/AGG to promote its commitment to vehicle electrification and expanding power electronics portfolio, showcase its continued development of joystick controllers and HMIs, and introduce a number of new and updated sensor products.

LATEST EV & HYBRID TECHNOLOGY
Curtiss-Wright’s highly-efficient and innovative traction inverters (CWTIs) are designed for use in hybrid and pure-electric applications for on-highway and off-highway commercial vehicles, with results from extensive testing on some of the world’s most powerful and efficient electric motors demonstrating improvements of up to 38% on peak torque and power, and a 3% efficiency improvement of the drive system (motor plus inverter) that results in an increase of up to 14% in vehicle range from a single battery charge.

Beyond its CWTIs, the company’s latest generation of custom power distribution modules (PDMs) – also referred to as high voltage junction boxes and DC charging units – are designed to enable the safe and efficient electrification of on- and off-highway vehicles while prolonging and maintaining battery life. Thanks to their reliable circuit protection, these system-level solutions offer protection of both vehicle occupants and electrical and electronic components from potentially harmful currents.

IN-CAB CONTROLLERS & HMI SOLUTIONS
In addition to its electrification portfolio, Curtiss-Wright will also be showcasing components and sub-system solutions, including its all-new JC8100 joystick controller. Offering high mechanical strength for very heavy-duty applications, the JC8100 features a center detent to provide guaranteed return-to-center and delivers a positive feel to the operator throughout its 5 million cycle rated life. 

Also new is the compact, handle-mounted DCS rocker switch, which offers single-axis forward/neutral/reverse functionality in a design that provides high lifecycle and excellent EMC and environmental protection performance thanks to its unique circuitry design.

The company will also use its stand to promote its HMI capability and showcase solutions incorporating multiple functions that can be operated with the use of just one hand, or via finger or thumb activation. 

SENSOR TECHNOLOGY
Curtiss-Wright is also unveiling several sensors, including upgrades to a non-contact rotary position sensor and valve position sensor, and new shaft-operated rotary position and swash plate sensors. 

New for the show is the dual-channel, pump-mounted swash plate sensor. Installed in a port on the side of the pump with the magnet installed in the swash plate, the sensor arrangement is designed to measure the angle of tilt of each cylinder in a swash plate pump to provide feedback on pump speed and aide efficiency. 

Also new is the SRH76X shaft-operated rotary position sensor, which features a heavy-duty, load-bearing shaft and transient protected circuitry in a high-strength, cast zinc-aluminum alloy body. The rugged, impact-resistant design of the new sensor makes it ideal for numerous heavy-duty, off-highway applications.

Based on the NRH271, the upgraded NRH-M27 non-contact, rotary position sensor offers the same functionality, outputs and low-profile, small-footprint design, but has acquired a rugged, aluminum housing ensuring the sensor is robust and suitable for heavy-duty on- and off-highway vehicle applications, especially those in challenging environments. 

Also being upgraded is the single-output VPT351 valve position sensor, with this next generation gaining a new chipset to provide more programmable points, improve linearity and ensuring accuracy to 1%. A dual-output VPT352 version will also follow.

Euchner UK Limited has continued its recruitment drive with the appointment of Mark Tsang as a Machinery Safety Consultant. 

Commenting on the appointment, Euchner’s Managing Director (UK&I) David Dearden says: “As a TÜV NORD Certified Machine Safety Expert, Mark Tsang is a well-respected engineer and joins us with extensive knowledge and experience in machinery safety consultancy. He has an extensive portfolio of qualifications covering DSEAR, ATEX, PED and PSSR; combined with expert witness writing and 20+ years’ experience of training and mentoring in engineering consulting.”.

He goes on to say that with the introduction of new standards, the frequent amendments to legislation and the advances in safety technology, including UKCA marking and PUWER inspections, many companies choose to outsource their machinery safety services requirements. “Machine manufacturers and end users must comply with UK and European directives, as well as international standards. Euchner Safety Services can provide you with professional solutions for all aspects of machinery safety, anywhere in the world. We help machine manufacturers and users meet legal safety requirements at every stage of machine and installation life cycles.” says David.

Mark joins Euchner’s already highly-skilled team of machinery safety experts and has all the knowledge and skills required to assess the safety of machines and equipment, identify potential hazards, and offer practical advice to control or eliminate those hazards. This includes conducting risk assessments, developing safety plans and procedures, and providing guidance on compliance with relevant safety regulations and standards.

To book your safety consultation, call Euchner’s Safety Technology Centre on +44 (0)114 256 0123, email services@euchner.co.uk or click https://bit.ly/3OK32oR.

Machinery safety specialist Euchner UK Limited is continuing to strengthen its team with the appointment of Hollie Dixon in a business development role. Hollie’s roles have been product-focussed and customer-facing since joining Euchner, so she is already well-versed on the company and its portfolio of machinery safety products and training solutions. 

Commenting on the appointment, Managing Director (UK&I) David Dearden says: “Hollie’s all-encompassing role helps support our major growth plans by being a key contributor to UK sales and marketing strategies for both products and services for Euchner.

“Her role will include research and analysis of key trends in new and existing markets, collaborating with both internal and external resources on new product launches and working closely with the sales and services teams on growth strategies and the continued development of Euchner’s key accounts network.”

Following a three-year hiatus, Curtiss-Wright Industrial Division has today deemed its return to the recent Bauma 2022 exhibition in Munich a huge success, apportioning this to its strategy of continued commitment to the vehicle electrification sector via an expanding portfolio of traction inverters (CWTIs) and power distribution modules (PDMs), which are designed in partnership with some of the world’s leading on- and off-highway vehicle OEMs.

Curtiss-Wright’s highly-efficient and innovative CWTIs are designed for use in hybrid and pure-electric applications for on-highway and off-highway commercial vehicles, with results from extensive testing on some of the world’s most powerful and efficient electric motors demonstrating improvements of up to 38% on peak torque and power, and a 3% efficiency improvement of the drive system (motor plus inverter)  that results in an increase of up to 14% in vehicle range from a single battery charge.

Beyond its traction inverters, Curtiss-Wright’s latest generation of PDMs have been developed for electric propulsion systems (EPS) and function as a gatekeeper between off-board DC chargers – called electric vehicle supply equipment (EVSE) – and the EPS, with the combination of Curtiss-Wright’s PDM and an OEM’s ECU contributing to a safe and controlled connection/disconnection of the EVSE to/from the EPS. Building on the company’s 20+ year heritage of supplying power electronics to leading commercial vehicle OEMs, Curtiss-Wright’s new generation PDMs have recently been approved for use and designed into a major OEM’s range of on-highway electric vehicles. 

Curtiss-Wright Industrial Division is a recognized leader in providing components and sub-systems that enable customer-specific solutions for on- and off-highway vehicles. These include medium- and heavy-duty trucks, buses and motor coaches, construction and agricultural vehicles, materials handling, and other specialty vehicles, as well as sophisticated wheelchairs and scooters for medical mobility.

The University of East Anglia (UEA) is no stranger to steam boilers from Fulton having been using the heat transfer specialist’s solutions for many years. But having replaced their ageing plant with new VSRT boilers, even they were surprised at just how efficient the installation would prove!

With steam being essential to the University and used extensively for humidification purposes – to ensure that the appropriate environmental conditions of 55% to 65% RH are maintained – and for the autoclaving of equipment and waste, any installation needed a form of redundancy in place from the outset.

Installed in 2004 and handed over to the facilities team in 2005, the University’s original installation therefore featured three J Series boilers, allowing for two to cope with daily requirement and the third as a standby for when steam demand was high or during servicing and maintenance schedules on the other boilers.

Commenting for UEA, Estates Project Lead Philip Page says: “Even during the original planning phases for the boiler plant room we knew that floorspace, headroom and access was going to be limited. With horizontal firetubes out of the question and many vertical boilers at the time requiring almost double the height of the boiler itself for maintenance purposes, Fulton’s J Series was the perfect solution.

“Fast forward to when we started the replacement programme for the J Series a review revealed that things, in the most part, hadn’t changed in the boiler market and no other boiler that could fit within the plant room was as capable or efficient. We therefore put the programme on hold.”

Thankfully for the University, when the time did come to complete the replacement programme, a market review in 2019 revealed that Fulton had just launched its all-new VSRT, the most radical change to vertical steam boiler design since the company pioneered the vertical tubeless boiler back in 1949; and the world’s first fully-wetted, refractory-free vertical tubeless boiler. The compact footprint of the VSRT also meant it was a perfect fit for the existing plant room.

Available with outputs from 160 to 960 kg/h, the VSRT boasts ultra-low NOx emissions of less than 20ppm, achieved thanks to the VSRT's combustion technology that features a modulating burner and furnace that have been purposely-designed as a single component and fully-matched with the VSRT in mind. This has helped Fulton to achieve up to 10:1 turndown capabilities and industry-leading performance of >82.5% gross thermal efficiency and 99.75% steam quality at 8 bar.

Having been in constant use for over 14 years, the University replaced all three Fulton J Series steam boilers with an all-new heat transfer system featuring three VSRT-50 boilers complete with all necessary ancillary plant including water treatment, chemical dosing, blowdown vessel and feedwater tank.

Because of the plant room’s situation – located in the middle of the building on the second floor – a temporary steam main was installed and piped to an external boiler plant solution that was hired so the facility’s steam supply could be maintained. A crash desk was then built two floors up, the end wall of the building removed, and the J Series boilers removed and replaced with the VSRTs. In total, the entire replacement process took six weeks to complete.

Two years after the VSRT installation was commissioned and handed over to the University’s estates team, a review of energy savings was commissioned to compared the old and new installations, with the results proving significant.

“The sustainability team compared the last 12 months usage of the three VSRTs to that of the three J Series boilers’ pre-Covid usage in 2019 and has reported a reduction in gas consumption of nearly 28% and over 57% for water.” says Philip. “Even if you don’t to take into account the recent cost increases in gas, these savings are significant and really impressive!”.

In addition to the gas and water savings, the sustainability report also identified an 85-tonne reduction in CO2 annually, savings that can be credited towards the University’s net zero goals. The University is also seeing an approximate 40% reduction in NOx emissions throughout the burner firing range.

As part of the new VSRT package, Fulton’s SCOPE boiler sequencing system was also specified which, as Philip Page explains, the University sees as being vital to the installation’s longevity.

“We operate an N+1 strategy at the University and most of the time two of the three boilers are firing to meet demand. The autoclaves are not always in use and during these times only one of the boilers is needed. However, we’re keen on maintaining equal operating hours across all three boilers and balancing water treatment across them too, so Fulton’s new SCOPE system enables us to automate weekly boiler changeovers to vary the lead boiler.

And while Philip can’t attribute the savings achieved from the boiler installation to the SCOPE itself, he is confident that the sequencing system will help to reduce maintenance costs by balancing operating times across the three boilers.

Beyond the impressive savings achieved, the University’s Estates team has also noted that compared to the J Series installation, the VSRTs are noticeably quiet in operation thanks in part to the fully-modulating burners running at lower levels when steam demand is low.

Summarising, Philip Page says that in the years that the University had Fulton boilers they really do tick all boxes. “We can’t fault their operation, and we can’t fault the Fulton service or customer support.”.

Steam specialist TLV Euro Engineering has launched the FJ32, a range of free-float steam traps designed for process applications including jacketed pans, heat exchangers and vulcanisers that, while adopting the universal QuickTrap® connection, can be regularly, safely and easily removed, repaired and reused.

Commenting for TLV Euro Engineering, General Manager Michael Povey says: “The new FJ32 steam traps really are exceptional! The FJ32 is a maintainable process steam trap with QuickTrap connections that, when used in conjunction with TLV’s recently-launched QuickStation™ QS10 steam trap station, can be safely isolated, the system blown down, existing trap removed and new trap installed and reopened for getting the process back up and running quickly. The FJ32 can then be maintained and put back into stock for future use.”

A reliable and durable stainless-steel steam trap for use on steam mains and process equipment, the two models in the FJ32 range – FJ32-X and FJ32-B – feature a two-bolt universal QuickTrap connector that facilitates inline steam trap replacement in either vertical or horizontal piping. This significantly reduces the time required for installation, removal, repair and maintenance; with removal of the old and installation of the new traps undertaken in a matter of minutes. This connection also allows traps to be positioned correctly regardless of pipeline configuration. 

Utilising TLV’s Free Float technology, the trap quickly adjusts to changes in the condensate load, with the three-point seating ensuring a steam tight seal even under low load conditions. The precision ground float provides an infinite number of contact surfaces with the orifice, ensuring negligible wear.

The high temperature (max. 350ºC) FJ32-B and low temperature (max. 240ºC) FJ32-X models come with different air venting methodologies to minimise start-up time. This, coupled with the maximum operating pressure of 32barG, offers a versatile trap suitable for a variety of applications.”

For further information, call TLV Euro Engineering on +44 (0)1242 227223, email sales@tlv.co.uk or visit www.tlv.co.uk. 

Industrial safety engineering specialist Euchner will use its stand at this year’s PPMA exhibition to launch two new and exciting products – the Industry 4.0 Ready CTS safety switch and CKS2 coded key system – and showcase its extensive range of guard locking products available for common fieldbus connections.

The all-new, one-fits-all CTS is Euchner’s first FlexFunction device and expands the company’s product range by sitting between the all-round CTP and specialist CTM safety switch solutions, by combining the best of both worlds in a single switch while offering maximum flexibility. A key innovation of the compact CTS – which is IO-Link compatible and Industry 4.0 ready – is the company’s new FlexFunction feature that, by using the transponder-coded actuator to determine the switch’s function, allows a single device to perform a wide variety of functions that would otherwise require several switch variants. Its compact dimensions, high locking force of 3,900N and suitability to mount in three orientations ensures the CTS is suitable for use across numerous safety engineering applications.

Combined with highly-coded, transponder-based keys, the new CKS2 from Euchner forms a safe system that meets the highest safety requirements for machine and installation lockout and starting. Thanks to the integrated evaluation electronics and depending on the key used, various safety engineering tasks are possible with the compact CKS2 key system. Additionally, combining it with Euchner’s IO-Link Gateways expands its applications and enables comprehensive diagnostic and communication functions. 

Unlike the CKS, the CKS2 can be integrated as a module within Euchner’s Multifunction Gate Box MGB2, expanding the functionality of the simple door interlocking solution to a small control terminal with access control.

Commenting, Euchner’s UK&I Country Manager David Dearden says: “The combination of MGB2 and CKS2 can be used across multiple sectors and for numerous applications to ensure process efficiency, create access rights flexibility, increase personnel and process safety, safeguard product quality and create transparency and traceability.”

The MGB2 is a unique interlocking or guard locking system for the protection of safety doors on machines and systems that, thanks to its modular approach, is more than simply a safety switch or bolt and offers a vast array of safety functionality. By incorporating additional safety modules to the MGB2, machine builders can include numerous functions, including guard locking, escape release, start/stop, emergency stop, etc. Its modular design also means the MGB2 can remove the additional need for a separate operator panel. And with networking opportunities available, it also reduces wiring and installation time. 

The MGB2, CKS2 and CTS are just three examples of the safety devices available from Euchner. For further information on these and other machinery safety solutions, the company’s technical and product support team will be on stand E68 at PPMA 2022 from 27th to 29th September.

Curtiss-Wright’s Industrial Division has today confirmed its continued commitment to its long-term strategy of advancing the electrification market with the extension of its traction inverter product portfolio. These latest CWTIs offer the most highly efficient and innovative design for use in hybrid and pure-electric applications for on-highway and off-highway commercial vehicles.

Commenting, Jason Watkins, GM Curtiss-Wright Industrial Division says: “Having successfully logged over two billion on-road kilometers since launching the first production units, these second generation CWTI models have been engineered to be the very best performing and most efficient IGBT inverters on the market today, using state-of-the-art technology to design and ensure end users receive peak performance from a CW engineered solution.”

The advanced motor control software within a CWTI ensures adaptive tuning works to create the highest efficiency between the inverter and motor, delivering a system that is both powerful and superior in performance. Results from extensive testing on some of the world’s most powerful and efficient electric motors have demonstrated improvements of up to 38% on peak torque and power. Furthermore, using the CWTI can improve the efficiency of the drive system (motor plus inverter) by 2% resulting in an increase of up to 14% in vehicle range from a single battery charge.

The latest CWTI models launch as 420kW vehicle-grade traction inverters for single (CWTI-S420) or dual (CWTI-D420) motor applications. To provide ultimate flexibility, the enhanced functionality of both models operates with multiple motor technologies, including AC induction, permanent-magnet synchronous (PMS) and interior permanent-magnet (IPM) types, to ensure improved range, longer battery life and lower running costs.

CWTIs offer unrivalled full fault protection and a high level of self-protection with both current and temperature measured directly on the IGBTs. These accurate temperature measurements deliver higher power from the motor, while current measurements offer superior short circuit protection to the system.

A pressure reducing valve from steam specialist TLV Euro Engineering has been installed at King’s College Hospital in London and operating on a daily basis for nearly 14 years without an overhaul or spares fitted.

The COSPECT pressure reducing valve was originally specified by TLV Euro Engineering and installed by a contractor in 2008 for the King’s College Hospital NHS Foundation Trust’s Ruskin Wing, the tallest building in the Denmark Hill campus and one housing many of the hospital’s neurological departments. Originally installed outside between two buildings at the site, the COSPECT valve has since been enclosed by further building works at the hospital campus.

Installed to reduce pressure in the main steam line from 8 bar to 2 bar, indirect steam is used for the hospital’s heating batteries and domestic hot water purposes, so the COSPECT valve is operating 24 hours a day, 365 days a year. 

It is estimated that the valve has achieved an average throughput of 950kg/h over its 14-year life, equivalent to 117,000 tonnes of steam. And in that time, the pressure reducing valve has never had any spares fitted, never been overhauled and has only occasionally had the operating pressures adjusted by the end user.

Commenting for TLV Euro Engineering, general manager Michael Povey says: “We were approached by Joji Abraham, the hospital’s estate officer, who was so impressed with the durability and longevity of the valve that he had no hesitation in contacting us when seeking a quote for a new plate heat exchanger system for the refurbishment of the Trust’s bone marrow ward. 

“The age of the COSPECT was subsequently confirmed by our regional sales engineer during an initial site audit for the planned ward refurbishment project, with the programme since being fully commissioned and featuring two new plate heat exchangers from TLV Euro Engineering.”

When the COSPECT was first introduced in 1985, TLV had been manufacturing steam traps and related steam products for over 30 years and was well aware of the limitations and inadequacies its customers were experiencing with conventional PRV’s. Based on this feedback, TLV applied its fluid control technology to solve the many associated problems including fluctuations in primary and secondary pressures and valve hunting and vibration.

The renowned COSPECT, which many believe to be the ultimate pressure reducing valve (PRV), uniquely combines three components in a single valve – a piston-operated pressure reducing valve, a cyclonical effects separator and a free-float steam trap. This innovation not only saves space but also simplifies system layout, piping and maintenance. The COSPECT also ensures that dry saturated steam is provided at constant pressure and temperature, which helps to improve product quality.

COSPECT’s separator achieves 98% condensate separation efficiency and the strainer removes any remaining rust or scale. In addition, the condensate that is separated out is quickly removed through the built-in free float trap. All of which produces a noticeable improvement in the quality of the steam, and its heat conductivity. This can lead to increased valve life as well as increasing the service life and performance downstream equipment. 

Maintenance is also simplified thanks to the COSPECT’s modular construction and use of PTFE gaskets, which makes the unit quick and easy to remove, or to maintain inline.

For further information, call TLV Euro Engineering on +44 (0)1242 227223, email sales@tlv.co.uk or visit www.tlv.co.uk.