The latest extension to the Meriam M200 manometer family is the M200-DI wet/wet differential pressure smart manometer. The handheld M200-DI meets the need of instrumentation and electrical shops for accurate calibration of differential pressure measurement of liquids and wet or corrosive gasses. This product line offers NIST-traceable, low-to-mid-range differential pressure measurement for any liquid or gas that is compatible with 316L stainless steel and Viton or Buna-N O-rings.
“With a common mode pressure rating of 1,000 PSI and full-scale ranges from 1 to 500 psid, the M200-DI is a tool that can measure live differential pressure [DP] across pumps, condensers and chillers or calibrate liquid DP transmitters,” says Dave Thomas, manager of instrumentation and measurement at Meriam. “Most non-isolated, portable DP standards cannot handle liquids or corrosive gases. They are susceptible to expensive damage when exposed to these materials themselves or to gas impulse lines with condensate or liquid slugs. The M200-DI protects the measurement sensor from the process fluid with a welded 316L stainless-steel diaphragm.”
The M200-DI is highly accurate, with NIST-traceable accuracy of ± 0.05% full-scale (FS), and an optional rating of ±0.025%. These measurements are independent of temperature effect from +23 °F to +122 °F for intrinsically safe models and -4 °F to +122 °F for general-purpose models.
The M200-DI is available in pressure ranges from 0-1 psid to 0-500 psid. All ranges are rated for 1,000 psi common-mode pressure.
“This number of ranges reduces the margin for error significantly,” says Thomas. “We have more ranges available to match up with more specific customer needs. The available DP ranges are higher than non-isolated DP handhelds.This is the best accuracy available in a handheld, isolated DP unit and makes the M200-DI suitable as a field portable standard. The 1,000 psi common-mode pressure is much higher than available non-isolated DP handhelds, making it useful for many more portable DP application needs.”
The M200-DI’s HI-side overpressure is 3x FS; LO-side overpressure rating is 3x FS, or 150 psi, whichever is less. Optional flushing ports can flush or clean P1 and P2 sides of the sensor with solvent to remove contaminants, potentially hazardous residue or dirty or congealed residue that could cause measurement errors. They can also vent air from the connecting tubing of liquid applications.
The display can read in any of 11 pressure units or be scaled linearly for special user units. The square root flow function displays flow in user-defined engineering units. The leak test function displays min/max values until user selected test time expires and then displays the leak rate per minute. Other features include min/max capture, display hold, user selectable damping and auto-record of up to 240 readings.
The M200-DI is available in an optional CULUS-listed and ATEX-certified intrinsically safe model, making it an ideal application for hazardous areas that are potentially explosive.
The polycarbonate, permanently dissipative base unit weighs 30 oz., and the sealed-membrane keypad comes with five dome contact-style buttons. The 2-line x 16-alphanumeric character LCD display shows characters 0.25 in. high with a contrast adjustment. It also has a two-stage backlight with visual over-range indication.
The M200-DI operates at temperatures from 23 °F to 122 °F (-5 °C to 50 °C) for the intrinsically safe model, and at -4 °F to 122 °F (-20 °C to 50 °C) for the general purpose model. It can be stored at temperatures between -40 °F and to 140 °F (-40 °C to 60 °C).
The unit runs for 100 hours on 4 AA batteries (included). Optional accessories include a hard carrying case, the M10-KIT, including hydraulic scissor pump, hoses, fittings and carry bag, and a 3-valve manifold assembly of 316 stainless steel.