VEGA VEGABAR 87 Submersible Pressure Transmitter, Metallic Cell

VEGABAR 87 submersible pressure transmitter with metallic measuring cell

The VEGABAR 87 is a hydrostatic pressure transmitter built to be lowered into a liquid and report the level above it from the pressure of the column. Where its ceramic sibling VEGABAR 86 targets clean or abrasive water, the VEGABAR 87 is the version for aggressive, viscous or hot media, because its sensing element is the metallic METEC measuring cell with a process diaphragm made of Alloy C276 and an oil-filled seal system. Seven Star LLC supplies the VEGABAR 87 in Oman and the GCC as an independent supplier in Muscat, and the sections below explain how the range is organised so that an RFQ can be written correctly the first time.

What the VEGABAR 87 measures and how the type is organised

The manufacturer describes the VEGABAR 87 as a pressure transmitter for liquids and viscous products with process temperatures up to 100 °C. It reads hydrostatic pressure, which a transmitter converts into level, and it can be used in tanks, wells, shafts and basins. The measuring ranges start at 0.1 bar for the smallest span and extend to 25 bar, so the same family covers a shallow sump and a deep process vessel. Accuracy is stated as better than 0.1 % in the standard version (a 0.2 % version also exists).

The cable or tube that carries the transmitter, the process fitting at the top and the housing that holds the electronics are all configured separately, which is why a single VEGABAR 87 order covers many physical designs. The product page shows cable-with-thread, cable-with-flange, tube and hygienic-tube variants, and an external housing option for installations where the electronics should sit away from the wet area.

Technical specifications of the VEGABAR 87

Approvals are configuration dependent. The manufacturer lists ATEX, IEC, FM, CSA, EAC, NEPSI, INMETRO, CCOE and UKEX schemes, intrinsic safety and flameproof protection types, WHG overfill protection and marine approvals. Confirm the exact certificate for the version you order before it goes into a hazardous area.

How the METEC measuring cell of the VEGABAR 87 works

Inside the METEC cell, a ceramic-capacitive CERTEC sensor sits behind a temperature-compensated chemical seal. The process diaphragm in Alloy C276 faces the medium, the pressure is passed through the isolating oil and an FeNi adapter to the ceramic cell, and the electronics turn the capacitance change into a current or digital signal. This arrangement is different from the dry measuring system of the VEGABAR 86, which exposes a ceramic diaphragm directly. The metal diaphragm is the reason the VEGABAR 87 is chosen for aggressive chemicals and for viscous products, while abrasive slurries remain the strength of the ceramic version.

Where the VEGABAR 87 fits in a level or pressure loop

The VEGABAR 87 is used for pressure and level in liquids and viscous products, for example in chemical, food and pharmaceutical processes, ultrapure water, lock control with two hydrostatic sensors, and waste water shafts. In oil and gas and power plants it suits process sumps, drain vessels, chemical dosing tanks and condensate pits where the liquid is warm or chemically demanding. With a second sensor as a slave, two VEGABAR 86 or 87 units form an electronic differential pressure system for pressurised level, level difference, flow, density or interface measurement, using a digital master-slave link. Related models on our site include the VEGABAR 82, 83, 81 and 86 and the VEGADIF 85.

Selection checklist for the VEGABAR 87

• Medium: aggressive or viscous liquids favour the VEGABAR 87; abrasive liquids favour the ceramic VEGABAR 86.
• Pressure span: smallest 0.1 bar, largest 25 bar. Choose the span that matches the liquid column, with margin for overfill.
• Temperature: up to +100 °C, minimum -12 °C. The oil fill limits low-temperature use.
• Mounting: suspension cable, connection tube, thread, flange or hygienic fitting. Cable length must reach from the fitting to the lowest measuring point and to the housing.
• Output: two-wire 4…20 mA (with or without HART), Profibus PA, Foundation Fieldbus or Modbus, depending on the control system.
• Hazardous area: intrinsic safety or flameproof, with the required marine, SIL or overfill approvals.
• Housing: plastic for general use, stainless steel for aggressive atmospheres, and the separate electronics version for very moist places.

Installation and commissioning of the VEGABAR 87

A suspension cable version must hang in a calm zone or inside a protective tube, so that lateral movement does not disturb the reading. The cable also contains the capillary for atmospheric pressure compensation, so the cable end must stay dry and open to air in a safe location, and it must not be sealed or kinked. Ground the installation according to the site practice, and keep the cable away from sources of strong electromagnetic fields; screened cable is advised if interference exceeds industrial test levels. For two-wire units, the supply and signal share the same cable, and the operating voltage of 9.6 to 35 V DC must still be available at the terminals after allowing for the loop load and the 22 mA fault current.

Setup is made with the pluggable PLICSCOM display and adjustment module, with PACTware and DTM software, or with a HART communicator. External displays such as the VEGADIS 81 or VEGADIS 82 can be added. After installing, set zero and span with the transmitter in the final position, and check the reading at a known level.

Maintenance and spares

The plug-in electronics are encapsulated against vibration and moisture and can be exchanged by the user. The measuring cell has no moving parts. Routine tasks are to inspect the cable, the cable gland and the suspension, to clean the diaphragm if the medium leaves deposits, and to compare the reading with a reference level. Record the serial number and the original configuration so that a replacement electronics can be set to the same range.

Typical applications in Oman and the GCC

In the Gulf the VEGABAR 87 suits chemical storage and dosing tanks at desalination plants, warm condensate and drain pits at power stations, process sumps in refineries and gas plants, and sewage shafts where the liquid is aggressive. High ambient temperature calls for a housing with sun protection and a cable route that is shaded; dust and humidity favour IP66/IP68 housings. Marine approvals are useful for offshore and port installations, where ship-class certification may be required.

Information to send with an RFQ for the VEGABAR 87

• Medium, density and maximum temperature.
• Required measuring range and whether the tank is open or pressurised.
• Suspension cable length or tube length, and process fitting type and size.
• Output signal and supply, including HART or fieldbus.
• Hazardous-area classification and approvals needed.
• Housing material, display needs and quantity.

Documents and quotation

A product information datasheet covering the VEGABAR 86, VEGABAR 87 and VEGAWELL 52 is attached on this page. Send the exact type code or the above details, and we will confirm availability and a quotation for the VEGABAR 87 in Oman and the GCC.