Howell Laboratories, Inc.

P. O. Box 389, 188 Harrison Rd., Bridgton Maine 04009 USA

(207) 647-3327	(888) 744-8359	FAX (207) 647-8273	contracts@howelllabs.com

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Certified to ISO 9001:2000

HLI News
New contract: 7600 ECOLCELL Chlorinators for DDG-113 and follow ships. [More]
New Products
Portable seawater chlorinator: Port-A-Chlor 8600. [More]
Upgraded medium-pressure air dehydrator, Model 8785, to replace our obsolete Model 7053. Call now for more information
Customized potable water treatment systems for Iraqi 35m patrol boats ... ... or for your application! Call now for more information
Around the World
January 2010: HLI supporting relief efforts in Haiti
At HLI
September 2008: David Douglas joins HLI as Director of Sales, Marine Products.

Model 7148

Low-Pressure Dew Point Monitor & Alarm

General Description:

The Model 7148 low-pressure dew point monitor and alarm system is designed to provide a simple, reliable method of measuring the dew point (moisture content) of low-pressure (0 - 150 psig) dry air systems. This is the same system incorporated in our popular low-pressure membrane dehydrators. Here, it can be used as a stand-alone device, or downstream of an air dehydrator whose built-in monitor/alarm system is unreliable or no longer supported by the original manufacturer.

Measurement is made by a highly sensitive aluminum oxide sensor, which is bathed by a continuous stream of air. Its impedance varies with the air’s moisture content, and is read by the humidity alarm controller. The operator may adjust the controller to achieve the desired alarm point. The analog dew point meter on the front of the control panel displays the current outlet air dew point. The entire alarm system may be calibrated by the operator without removal from the unit.

If at any time the outlet air moisture content exceeds the controller’s set point, the controller activates the humidity alarm. This alarm includes the flashing red humidity alarm lamp, the audible alarm (buzzer), and the humidity alarm remote connection. The buzzer can be disabled by the audible alarm switch. The humidity alarm remote connection is a relay closure (closed on alarm) with a 6800-ohm resistor in parallel.

Specifications:

• Fully qualified for high-impact shock per MIL-S-901, Grade A; Type I vibration, 4 - 50 Hz, per MIL-STD-167-1; EMI/RFI per MIL-STD-461.
• Indicating Range: 0° F to -60° F dew point.
• Alarm Point: Operator-adjustable from 0° F to -60° F dew point. Factory pre-set at -30° F unless ordered otherwise.
• Indicator: Meter movement.
• Alarms: Local lamp and audible alarm; remote "dry contacts" with 6800-ohm supervisory resistor.
• Operating Pressure: 0 to 150 psig.
• Electrical Requirements: 115 VAC, 60 Hz, single-phase, 1 ampere.
• Fittings: Unions per MIL-F-1183 standard; others available on request.
• Dimensions:
  • Sensor Unit: 20" W x 6" H x 6" D.
  • Control Panel: 9" W x 12" H x 7" D.
• Weight: 20 pounds.
• Mounting:
  • Sensor Unit: Support on pipe hangers (by customer).
  • Control Panel: Mounting tabs.

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Last updated: 01/27/10 Webmaster: Al Friend © 1999-2010 Howell Laboratories, Inc. All rights reserved.		Printable Adobe Acrobat version
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