Series-B-190Configuration

Supported Applications

The Series B190 is a displacer-type liquid level control designed for single-stage operation with adjustable differentials. As part of the Mercoid (a division of Dwyer Instruments, Inc.) product line, these mechanical controls utilize a suspended displacer system to monitor liquid levels in tanks and vessels.

The series is engineered for specific gravity ranges from 0.6 to 1.2. The control head mounts level on top of the vessel, with the displacer assembly extending into the process media via cable. As the liquid level rises or falls, buoyancy changes alter the effective weight of the displacers, actuating internal switches.

Operating Conditions & Performance

The Series B190 operates within specific temperature and density parameters defined by factory settings. The documented operating temperatures are 100°F and 200°F, with performance characteristics varying based on the selected setting. Specific gravity should not vary more than ±1 from the factory setting, and process temperature should remain within ±50°F of the set point.

Performance dimensions for single-stage adjustable differential models (Series B190) are detailed in specification tables covering specific gravities from 0.6 to 1.2 at both 100°F and 200°F settings. Key dimensional parameters include:

• A Max.: Ranges from 116-1/2" [2959] (at SP GR 0.6, 100°F) to 120" [3048] (at SP GR 1.2).
• A Min.: Ranges from 6-1/2" [165] (at SP GR 0.6, 100°F) to 9-1/2" [241] (at SP GR 1.2).
• C Max./Min.: Adjustable differential dimensions vary by specific gravity and temperature setting.

Single stage displacer controls are noted to tolerate much wider fluctuations of specific gravity and temperature as indicated in the provided tables compared to other configurations.

Configuration Options

The Series B190 offers configurable options regarding switch types, process connections, and materials. The series supports both mercury switches and enclosed metal contact snap-action switches with distinct electrical ratings:

• Mercury Switches: AC or DC; 10 amp at 120 volts; 5 amp at 240 volts; 3 amp A.C. at 440 volts.
• Enclosed Metal Contact Snap-Action Switches: 12 Amp, 120 volts AC; 5 Amp, 240 volts AC; 1/2 hp, 120/240 volts AC; D.C. 0.5 Amp at 125 volts; 0.25 Amp at 250 volts.

Process connections are available with a standard stand flange of 4" 125# C1, though other sizes and materials are offered. Electrical connection is provided via a 3/4" NPT conduit connection with an internal terminal block.

Wetted material options include:

• Displacers: Porcelain (also available in other materials).
• Cable: 316 stainless steel, standard length 10 ft with longer lengths available.
• Stops: 316SS.

The system is factory-set for specific gravity and temperature. The minimum differential (c) can be reduced approximately 1" by removing the cable clamp from between the displacers and turning the lower displacer so the flat side is up; however, if a narrower differential is needed, a Type A190 control is indicated.

Key Product Differences

The Series B190 distinguishes itself within the broader family by offering single-stage operation with adjustable differentials. This contrasts with:

• Series A190: Single stage, fixed differentials (specific gravity 0.5 to 1.2).
• Series 195-4 through 195-8: Two-stage configurations with either fixed or adjustable differentials and varying spread capabilities between stages.

Circuit arrangements for the series include SP-ST (Close on level DROP/RISE) and DP-ST options, identified by specific spec numbers such as No. 4820, No. 4821, No. 4815, No. 4814, and No. 4813 depending on the circuit response to liquid level changes.