With advances in the manufacturing process and using techniques such as ‘GED’ – Gas Enhanced Drying, laser trimming and on-board temperature compensation, the ceramic pressure sensor is now as repeatable, long term stable and thermally stable as other sensing techniques but offering a two clear advantages!… Price and chemical compatibility!

There are two main product types that are available from Impress Sensors & Systems:

ME501/505 2-part ceramic pressure sensor

ME501/505 2-part ceramic pressure sensor

This ceramic pressure sensor is based on a standard piezo-resisitive Wheatstone bridge screen printed onto a diaphragm which is then hermetically sealed to a body and offers a wide pressure range, gauge, absolute or sealed gauge reference and also a better overall performance regarding non-linearity and hysteresis.  Pressure ranges are from 0.5 bar through to 600 bar.

ME651/662 Monolith ceramic pressure sensor

Monolithic in design this is moulded from a single piece of ceramic with the Wheatstone bride printed on the back of the pressure sensor, this means the cost of the material and also the processing time is greatly reduced from the 2-part design

ME651/662 Monolith ceramic pressure sensor

which in turn enables us to achieve a much lower selling price.  The minimum pressure rang is slightly increased to 2 bar and the maximum pressure sensor range reduced to 400 bar.  The linearity is just as good as the 2-part but on certain pressure ranges the hysteresis is greatly increased, this is due to the influence of the mechanical structure whereas on the 2-part this it eliminated by the design.

Both designs, being based on Aluminium Oxide (Al2O3)or alumina are virtually chemically inert which means that they can be used on the majority of applications and prevent the necessity of exotic chemical seals to be used on a stainless steel silicon based pressure transmitter design.  We manufacture aggressive chemically compatible pressure sensors based on using a ceramic pressure sensor, PVC, PVDF or PEEK housing and seated onto a chemraz or Kalrez O ring seal and this offers compatibility of the highest order!

The sensors can either be supplied in the ‘raw’ format for integration into customer specific housings and manifolds or we can work with you to design a suitable housing that fits the requirements of the application.  We design all our own electronics which means we can also tailor the output signal and condition it to your exact interface requirements.

Product Datasheet: ME501/505 datasheet, ME651/662 datasheet

Product Page: Ceramic pressure sensor products page

If you have any applications you wish to discuss or any questions questions regarding this product then please contact sales here sales@impress-sensors.co.uk

Ceramic Pressure Sensor offers multiple solutions! is a post from: Impress Sensors

IMD Differential Pressure Transmitter

The IMD Differential pressure transmitter has been developed to cater for applications that may only be looking at a low level of differential pressure (from 350mbar) but with a HIGH static line pressure up to 200 bar!

The IMD has a differential pressure range from 350mbar through to 35 bar and can have a nominal static line pressure of up to 200 Bar which makes this product ideal for low differential pressure measurement across a filter on a pipe or manifold that may have excessively high line pressures.  This has always been an issue for applications and usually results in customers compromising on the resolution and accuracy by using a higher pressure range than what they actually need to achieve the high line pressure requirements!  Outputs include 2 and 3 wire 0/4-20mA and voltage outputs which are ideal for most conventional HMi’s, PLC’s, signal conditioners and data loggers.

The sensing technology used within the IMD is a strain gauge fabricated as part of the silicon chip.  This is then isolated from the media by means of an oil filled cavity and a stainless steel diaphragm which enables the product to be used with liquids or gases.  The housing and sensor is made from stainless steel and incorporates an internal Viton O ring seal making this product suitable for a wide range of applications.  Every device is temperature compensated and calibrated and supplied with a traceable serial number and calibration certificate. The integrated electronics can be configured to have either voltage and current outputs with zero and span adjustability via the internal Pots.

With optional ATEX approval to EEx ia IIC T6 extends the possible applications to Petrochem & Process Industry, other applications include the following:

• Hydraulics
• Pneumatics
• Filter condition monitoring
• Agricultural machinery
• Laboratory testing
• Mechanical engineering
• Environmental engineering
• Automotive testing
• Pumps & compressors
• Medical testing
• Waste water & sewage

Other applications for differential pressure measurement include tank level measurement in a sealed vessel where the air pressure in the top of the tank is measured relative to the hydrostatic pressure of the liquid in the vessel.  Flow measurement in a pipe by means of an orifice plate which creates a differential pressure dependant on the size of the orifice plate.  More can be seen about applications and typical installations following this link.

Product Datasheet: IMD Differential pressure transmitter

Product Page:  Differential pressure sensors

If you have any applications you wish to discuss or any questions questions regarding this product then please contact sales here sales@impress-sensors.co.uk

IMD Low Differential pressure transmitter with 200 Bar line pressure! is a post from: Impress Sensors

IMP Industrial Pressure transmitter

The IMP Industrial pressure transmitter is now offered on a standard 4 day delivery which CAN be improved for urgent requirements!

The IMP is built on a Kan-Ban basis so part assembled bodies are held on the shelf ready for calibration via the ASIC based Microprocessor and all that is required then is the electrical connector to be fitted as specified by the customer.  This enables production to perform a quick pressure range of the device, calibration and installation of Electrical connection.  The options include Plug & Socket, IP66 Cable, IP67 Cable M12 Connector, Amphenol Connector and others on request.

The Pressure transmitter is based on a piezo‐resisitive ceramic pressure sensor giving it excellent media compatibility.  The housing is made from stainless steel with a choice of internal O ring seals to ensure the product is suitable for a wide range of applications.  Every device is temperature compensated and calibrated and supplied with a traceable serial number and calibration certificate.  The electronics incorporate a microprocessor based amplifier, this means there are no adjusting pots and therefore the electronics are very stable, specially in high vibration / shock applications.

We cover pressure ranges from 500mbar through to 700 bar with this product and have options for Absolute, Gauge and Sealed Gauge reference.  The electrical outputs available are  mV, Volts and 4-20mA Current output as standard.  If your application requires improved performance from the standard<± 0.25% then we can offer a <±0.1% within 7 days delivery on any pressure range.

IMP pressure transmitter up to 150°C

We have options of different housing material such as PVC, PVDF & PEEK to solve applications with aggressive chemicals.  The ceramic sensors are ideal for these applications as they are virtually inert.  We can also supply a version which has an integrated temperature cooling element.  This will enable the transmitters to be exposed to 150°C media temperatures!

Product Datasheet: IMP Industrial Pressure Transmitter

Product Page: Industrial pressure transmitter product page

Please contact Impress for any questions about the pressure sensors, transmitters and transducers we offer: sales@impress-sensors.co.uk

IMP Industrial pressure transmitter on 4 day delivery! is a post from: Impress Sensors

Some specific advantages can be gained from using pressure transducers that operate on the Linear Variable Differential Transformer (LVDT) principle. Here, a pressure responsive element is directly coupled to the core of a linear LVDT.

Pressure Sensors integrate LVDT Technology

An LVDT is an electro-mechanical device that produces an electrical output that is linearly proprtional to the displacement of a moveable core. It consists of a primary coil with two secondary coils placed on either side of the primary coil. A rod-shaped soft magnetic core inside the coil assembly provides a path for the magnetic flux linking the coils.

When the primary coil is energised by an alternating current, source voltages are induced in the two secondary coils. The secondary coils are connected in series with the start of each winding being connected together. This arrangement produces a net zero signal output from the secondaries when the induced voltages are equal in each coil. This condition occurs when the core is centrally disposed between the two secondaries. A movement of the core leads to an increase in magnetic coupling to the coil in the direction of movement and a reduction in of magnetic coupling to the other coil producing a net output signal from the connected secondaries. Movement in the opposite direction produces an identical signal output but of opposite phase.

To form a pressure transducer, the core displacement of the LVDT is produced by the movement of a metallic pressure responsive diaphragm.

Some LVDT pressure transducers are fitted with a single, precision metallic diaphragm with over range pressure protection stops as the pressure-responsive element. This arranagement allows the manufacture of differential, gauge and absolute transducers, which all employ a common design philosophy.

The distinct advantage of using an LVDT transducer is that the moving core does not make contact with other electrical components of the assembly, as is the case with other types. This means an LVDT transducer offers high reliability and long life.

The LVDT design also lends itself very well to easy modification in order to fulfil a whole range of different applications in both research and process engineering.

Positive Over-pressure

An LVDT gauge-type pressure transducer lends itself very well to being protected from damage by positive over-pressure. The sensor’s safe limits are normally much greater than those specified by the manufacturer and unrivalled by alternative technologies. Often, the sensor will still operate above the specified over-pressure limit, but at a reduced accuracy. In contrast, silicon and thick-film pressure sensors do not exhibit this level of over-pressure capability.

Rupture Integrity

Unlike silicon and thick film pressure sensors, LVDT pressure transducers provide process containment for applied static pressures of up to 400bar or higher. Special welding techniques are used to improve rupture integrity, supported by an over-pressure stop. In addition, the diaphragm material can be relatively thick, offering enhanced durability and improved resistance to pin-holing (corrosion).

Shock Loading

LVDT pressure transducers can be impact shock-loaded in all three axes without sacrificing the performance of the sensor. The diaphragms are not made from brittle materials and so failures due to shock loads are rare.

Fluid Fill

Process compatibility is also a key requirement when sourcing a suitable pressure transducer. With LVDT pressure sensors, flush diaphragms can be provided rather than fluid-filled units. This offers enhanced process compatibility and does not limit the temperature range. In addition, if the pressure sensor is required to perform in a hygiernic application such as a dairy or food processing application, a low cost silicon-filled sensor will require a barrier of some sort to prevent conatmination. In contrast, the design of an LVDT pressure sensor makes it inherently suited to hygienic, FDA-compliant applications.

Process Interface Options

LVDT pressure sensors open up a wide range of process interface and wetted material options for the user. With sufficient understanding of the application, the sensor manufacturer is able to optimise the measurement solution at the lowest cost.

Transmitter Electronics

LVDT pressure and level transmitters enable the user to adjust both zero and span settings. Analogue and digital signal processing types are available. Most analogue transmitters will offer zero and span adjustment, square root option, time constant and ±100 per cent offset adjustment.

Digital electronic types offer local configuration of zero and span, along with the ability to turn on or off the instrument preset non-linear function. Digital types can normally be configured via an integral communication port.

Submersible type LVDT pressure sensors normally use digital signal processing and have the option of either a simple single wire configuration port that allows zero and span calibration together with the ability to turn on or off the instrument preset non-linear function, or full RS485 communication that enables full configuration of the transmitter.

LVDT Pressure Transducers for the Nuclear Industry

In the nuclear sector, LVDT pressure transducers are utilised in reactor research and development work; leak detection on nuclear transport flasks; detection of leakage from Magnox storage ponds; monitoring material storage pond levels; storage room pressure monitoring; level measurement in effluent treatment works; and glove box gas handling systems. LVDTs are even used in weapons de-commissioning, where the sensor must withstand highly aggressive chemicals such as Hydrobromic Acid and where radiation immunity is critical.

LVDT pressure transducers are generally favoured by the nuclear industry because they offer distinct advantages over alternative pressure sensor designs.

LVDT tranducers provide high immunity to radiation and can be stable to 10 exp6 rad, with some manufacturers offering versions that allow up to 10 exp12 rad without damage to the sensor.

LVDT sensors can also withstand higher temperatures, with high radiation continuous working options typically available up to 200 deg C.

LVDT sensors also benefit from the fact they can have remote electronics up to 1,000 metres or more of cable between the sensor and the signal conditioning electronics. This allows the sensor to operate in extreme radiation, temperature and high magnetic fields, conditions that would normally damage the conditioning electronics.

In LVDT sensors, the segregation of the transducer from the pressure-responsive element enables many specialist materials to be used for compatibility with the process fluid. Manufacturers can therefore produce sensors with Tantalum, Hastelloy, stainless steel, Monel, Inconel and PTFE sintered coatings.

Products Page: LVDT based pressure sensors & transmitters

For more information on these products please contact Impress sales on sales@impress-sensors.co.uk

Pressure sensor utilises LVDT technology! is a post from: Impress Sensors

Pressure sensors vary considerably in their design technology used, performance and application.  Pressure sensors often can be referred to as pressure transducers, pressure transmitters, pressure indicators or pressure switches – are used to measure the pressure of gases and liquids (fluids).

Pressure is an expression of the force and is normally stated in terms of force per unit area. A pressure sensor will generate an electrical signal relating to the pressure imposed. This signal is either analogue or digital in more modern designs, although optical, visual and auditory signals are also common.

Pressure sensors, basics of pressure measurement

Industrial pressure transducers normally have a diaphragm type design that uses strain gauges, which are either bonded to, or diffused into it, with the strain gauges acting as resistive elements. Under the pressure-induced strain, the resistive values change. In capacitive technology, the pressure diaphragm is a single plate of a capacitor that changes its value under pressure-induced displacement. These are probably the most common technologies used in industrial applications for their favourable price/performance ratio.

Pressure is measured against a reference, which greatly depends on the application and installation of the sensor. Depending on the relevant pressure, the term ‘absolute’ is used when the reference is vacuum; ‘gauge’ is used where the reference is atmospheric pressure; and ‘differential’ is used where the sensor has two ports for the measurement of two different pressures.

Pressure sensors are used in a wide variety of applications for control and monitoring purposes. Pressure sensors can also be used to indirectly measure other variables such as liquid or gas flow (in conjunction with an orifice plate), speed, fluid level and also altitude.

Due to the wide range of technologies available, pressure sensors vary considerably in their design, performance, application and cost. Every technology has its own benefits and reasons for selection within an application.

When used directly to measure pressure, applications include meteorology instrumentation, aerospace and defence, research and development, automotive and other machinery or equipment that has pressure functionality implemented. Other applications for pressure sensors include hydraulic and pneumatic systems, water depth, offshore & marine, waste water & sewage, oil & gas exploration, nuclear, medical, food and beverage processing, tank level/contents, HVAC systems, agricultural equipment, environmental monitoring and chemical & processing plants.

Pressure Products Page:  Impress Sensor pressure products page

Basics of pressure measurement is a post from: Impress Sensors

Battery Operated Digital Pressure Gauge

The BAROLI battery operated digital pressure gauge has an unrivaled continuous operation time of 1800 Hours!  Using 2 x half AA battery’s that are available from most local  battery suppliers, the BAROLI can work without having the power turned off for up to 1800 hours (75 days).  The device can also be set via the push-buttons on the display to have an automatic switch off after 1,2,3,4 or 5 minutes to further extend this lifetime.

The digital pressure gauge is available with two different sensing technologies installed internally, the first option is the low cost ceramic piezo-resistive pressure sensor which has a pressure range from 1 bar up to 400 bar Gauge or Absolute.  The second option is the stainless steel media isolated silicon sensor with pressure ranges from 100mbar through to 600 bar also in gauge or absolute reference.

The accuracy performance of the ceramic sensor will offer better than 0.25% FS BFSL and the silicon sensor with the improved resolution will offer better than 0.125%.   Both version are temperature compensated and offer excellent stability.  The update rate of the displayed reading is 5 per second which is more than adequate when being used as a visual indication of changing pressure.

The display is LCD with a very visible 40 x 30mm screen size.  The main display area is 4.5-digit 7-segment with a digit height of 11 mm.  It also has an information line on the display which is 6-digit 14-segment and a digit height of 7.5 mm which displays useful information when navigating the menu.  The Housing of the display is PA material with a unique feature that is can rotate in 2 axis through 270 degree’s.  This means where ever the display is installed with a simple twist and turn of the display unit you can always make the display visible to the user!

Some interesting features  on the menu options…

1) Zero ‘Tare’ – This means if there is an offset in the pressure line or after fitting a pressure seal there is a slight offset then this can be removed by a simple push of the buttons on the display

2)  Changing of engineering units – the standard is Bar but this can be changed to mbar, PSI, mWs, inHg, cmHg, mmHg, kPa, MPa without affecting the calibration.  The device will automatically apply the calibration factors required for the change of scale!

3)  You can tell the device what switch off time you require or leave the display on permanently

4)  Minimum and maximum display of the pressure reading – When using the device and you need to know what the minimum pressure or maximum pressure the device has been exposed to then this can be looked up in the menu, this is particularly useful when diagnosing a fault in a process where the sensor can record and over pressure for example

5)  Re-calibration of the full scale pressure range – If you have a pressure source and you feel it is necessary to re-calibrate the device to take out any offsets then this can easily be done by generating the correct pressure and pressing the span calibration in the menu

6) Reset to factory default – When you just need to reset the calibration to factory default if for instance you’ve calibrated the device to the incorrect pressure then all is not lost, just restore to factory default settings with a couple of presses of the buttons!

Impress Carry a stock of these devices so are available for ex-stock delivery internationally!  The standard process connection is G 1/2″ male to DIN 3852 but other fittings such as NPT are also available to order.

Product Datasheet: BAROLI Battery operated digital pressure gauge

Product Page: Pressure products with displays

If you have any questions or would like a quotation on the BAROLI battery operated digital pressure gauge then please contact us using either the contact form or directly by email to sales@impress-sensors.co.uk

Battery Powered Digital Pressure Gauge – 1800 hours continuous operation! is a post from: Impress Sensors

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We hope to cover all of the products in the range with product releases and also new products also, just as a reminder of some of these categories and please see below, the links will take you to the relevant product section.

Pressure Sensors

Temperature Sensors

Level Sensors

Distance Sensors

Indicators

Controllers

Data Loggers

Data Recorders

Calibration Equipment

SIL2 Approved Products

ATEX approved Products

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