Meriam 1120P

1120P Series Indicators (PORTABLE)
Indicator models 1123, 1124 and 1126 have 3”, 4.5” and 6” dials respectively. A variety of scales for differential pressure, flow and level can be supplied. The 1120 Series is widely used in industrial process plants, power plants, pollution control facilities and in the cryogenic gas industry.

The Meriam Model 1120 Differential Pressure Unit is a proven and reliable sensing element used in all Meriam Bellows Gauges. It is available in ranges as low as 0-30” w.c. or as high as 0-500 PSI. The light weight and compact differential pressure unit incorporates a rupture-proof and leak-proof bellows plus other features that ensure ruggedness and reliability. This basic unit is suitable for activating indicators, recorders, transmitters, switches, and controllers and is available as a separate assembly for that purpose.

The 1120 consists of a high and a low pressure bellows connected to each side of a center plate. The bellows are enclosed in end housings which in turn are bolted to the center plate. The interior of the bellows and center plate is completely filled with a clean, low freezing point, non-corrosive fill fluid. As differential pressure is applied, this fill fluid moves between the bellows through a field adjustable dampening valve in the center plate. Other external dampening devices are not required for measurements of pulsating differential pressure. Also, the Meriam 1120 incorporates a special design which completely isolates the process fluid from the center plate.

When differential pressure is applied to the high and low pressure connections, the high pressure bellows contracts, forcing fluid through the center plate into the low pressure bellows which expands. The resulting linear motion of the low pressure bellows is converted to a 6 degrees rotary motion of the output shaft through temperature compensating linkage. Over-range protection up to the pressure rating of the housing is provided by two fluid shut off valves located on this linkage. The output shaft is part of a low friction, “O” ring sealed shaft and bearing assembly which carries the rotary motion to the external area of the bellows unit and into the instrument case.

1126P-2 Portable Indicator

The 1126P-2 is designed for portable applications. Typical examples are periodic measurements of the pressure drop across filters, balancing of flow rates in heating and cooling systems and checking of back flow prevention devices. Meriam’s 1126P-2 consists of an 1126 D/P Indicator with 3-valve manifold and piping, 2 hoses and quick disconnects. Each instrument system is assembled as a complete package with all the accessories mounted in a rugged, light weight case. When used as a flow measuring device, the instrument normally comes with a 0-100% square root scale. With all flow elements designed for the same differential, multiplying the scale reading by the primary element’s full flow design value gives readings directly in flow units. Scales in flow units, inches of H20, PSI and metric units are also available.