Rosemount Magmeters and Rosemount 8705 Series: Flanged Electromagnetic Flow Instruments

Quick Answer: The Rosemount 8705 Series is a flanged electromagnetic flow meter for water, wastewater, chemical, and slurry lines. Silver Automation Instruments builds a direct replacement with the same face to face dimensions, liner options, and 4-20 mA HART output at a lower price. Send your pipe size (DN), flow range, pressure (bar), and temperature (°C) to get a quote for a DN15 to DN600 replacement.

What the Rosemount 8705 Series Covers

Rosemount magmeters in the 8705 line are designed for process and utility lines. The flow tube is flanged and available in sizes from DN15 to DN900. Common liner materials are PTFE, PFA, and hard rubber. Electrode options include 316L stainless steel, Hastelloy C, titanium, and tantalum.

The meter handles clean water, wastewater, acids, caustics, and slurries with solid content up to 30 percent. Conductivity must stay above 5 µS/cm for a stable reading. For water and wastewater plants this is rarely a problem. For deionized water or pure solvents a magmeter will not work.

Why Engineers Replace the 8705 with a Silver Automation Instruments Meter

Price is usually the main driver. A Rosemount 8705 with a 8712 transmitter costs more than many project budgets allow. Silver Automation Instruments offers a flanged electromagnetic flow meter that matches the process connection and output signals. The meter body is welded and pressure tested to EN 1092-1 or ASME B16.5 flange standards. The transmitter supports 4-20 mA HART, pulse, and RS485 Modbus.

We have seen this on customer sites many times. A wastewater plant in Chile needed six DN150 flanged magmeters for sludge return lines. The Rosemount 8705 delivery time was 8 weeks. Our replacement shipped in 3 weeks. The meters measured 0 to 400 m3/h with an accuracy of 0.5 percent of reading.

Key Specifications for the 8705 Series Replacement

You should check liner and electrode compatibility before you order. PTFE liner is common for chemicals and high temperature streams. Hard rubber is common for water and wastewater. PFA liner covers high vacuum and aggressive acids. Electrode material depends on the process fluid. 316L works for water and weak chemicals. Hastelloy C works for acids. Titanium works for seawater and brine. Tantalum works for hydrochloric acid service.

Process pressure ratings are PN10, PN16, PN40, and ASME 150 lb. Fluid temperature can range from -20 °C to 150 °C depending on the liner. The transmitter has a local display and can be remote mounted if the pipe runs in a high vibration area. For hazardous areas, ATEX Zone 1 and Zone 2 approvals are available on request.

Common outputs are 4-20 mA HART, pulse, and RS485 Modbus. Some projects also need a PT100 temperature input for heat metering. We can supply that option. The minimum conductivity for standard electrodes is 5 µS/cm. For low conductivity fluids above 0.5 µS/cm you need a special capacitive electrode design.

Sizing and Installation Notes

Most engineers select a magmeter size that matches the pipe diameter. The flow velocity should stay between 0.3 m/s and 10 m/s for stable accuracy. For abrasive slurries keep velocity below 3 m/s to protect the liner. For clean water you can run 5 m/s without a problem.

Installation is straightforward. You need a straight run of 5 pipe diameters upstream and 3 pipe diameters downstream. The meter must be full of liquid at all times. Gas bubbles cause reading errors. Never install a magmeter at the highest point of a pipe where air collects. A paint manufacturer in Southeast Asia learned this after installing a meter on a vertical line with downward flow. The meter lost signal when the pipe was not full. We moved the meter to a horizontal section and the reading became stable.

Rosemount 8705 Series and Silver Automation Instruments Flanged Magmeter

The Rosemount 8705 is a proven instrument. It works well in refineries, chemical plants, and large water networks. The limitation is cost and lead time. A Silver Automation Instruments flanged electromagnetic flow meter gives you the same process connection and signal output. The housing is IP67 or IP68 rated. The converter has a backlit LCD and supports forward and reverse flow totalizing.

Here is the thing. Many replacement requests come from maintenance teams who need a meter fast. They do not want to re-engineer the pipe or change the flange. We keep common sizes DN50, DN80, DN100, DN150, and DN200 in stock for fast shipment. Larger sizes DN250 to DN600 are built in 7 to 10 working days.

Send us your pressure (bar), temperature (°C), pipe size (DN), and flow range. We will reply with a model recommendation and a formal quote. You can reach Silver Automation Instruments by Tel at +86-25-68650347, WhatsApp at +86-25-52155837, or WeChat at +86 15365082610.

FAQ

Is the Silver Automation Instruments flanged magmeter a drop in replacement for the Rosemount 8705 Series?

Yes. We match the flange standard, face to face dimension, liner, electrode, and output signal. Send the Rosemount model code and we will cross reference the replacement.

What liner and electrode materials are available?

Liners are PTFE, PFA, hard rubber, and soft rubber. Electrodes are 316L, Hastelloy C, titanium, and tantalum. We also offer a ceramic liner for abrasive slurry in small sizes.

What is the delivery time for a DN100 replacement meter?

DN100 is a standard stock size in our warehouse. It ships in 3 to 5 working days after order confirmation. For a remote transmitter version add 2 working days.

Does the meter support HART and Modbus?

Yes. The standard output is 4-20 mA HART with pulse. RS485 Modbus RTU is an option. You can use the local buttons or a HART handheld to set the range and totalizer.

What are the minimum conductivity and pressure ratings?

Standard minimum conductivity is 5 µS/cm. Optional capacitive electrodes work down to 0.5 µS/cm. Flange pressure ratings are PN10, PN16, PN40, and ASME 150 lb depending on size.

For a fast quote on a Rosemount 8705 replacement or any flanged electromagnetic flow meter, contact Silver Automation Instruments. Tel: +86-25-68650347. WhatsApp: +86-25-52155837. WeChat: +86 15365082610.

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