Reliability & Accuracy Neo-Dyn Industrial Catalog ®

People Are the Key to Our Success Neo-Dyn’s founders had more than 200 years cumulative experience in the design and manufacture of pressure switches when they started the company in 1973. Over the years, we have built a substantial work force of skilled professionals in every discipline, from design and testing, to marketing and manufacturing. Many of our people have been with the company since its beginning. In-House Capabilities for Total Control Having total in-house capabilities, we provide our customers with high quality products with rapid delivery and competitive prices. Broad Range Capabilities...

Repeatability, Accuracy and Maintenance for Pressure Switches REPEATABILITY Repeatability is the maximum set point deviation of a single pressure switch under one given set of environmental and operational conditions. Since adjustable pressure switches can be set at any discrete set point within its given adjustable range this is the most common performance criteria stated by the manufacturer. A general repeatability statement is that a ITT Neo-Dyn pressure switch will repeat within ± 0.5% of its set point when set in the upper 80% of its adjustable range for set points above 10 psig. Exceptions...

Temperature Limitations for Pressure Switches Pressure switch applications often have media temperatures that are in excess of our published specifications. Even though most of Neo-Dyn’s switches can actually withstand temperatures higher than those listed, they are published for varying reasons that include effects on; set point shift, decreased life expectancy, or in some cases, damage. O-rings themselves have limitations even though they are capable of temperatures higher than those we publish for the switches. Generally speaking, Buna-N and EPR are good up to 250°F (121ºC), Viton up to 400...

Quick Reference ChartsAdjustable Pressure Switches ADJUSTABLE PRESSURE RANGE^H * Applicable to Nema 3, 4 and 13 enclosure only

Quick Reference Charts - continue Adjustable Differential Pressure Switches WETTED MATERIAL ADJUSTABLE PRESSURE RANGE DOUBLE BRAKE ELECTRICAL FORM Adjustable Temperature Switches ADJUSTABLE TEMPERATURE RANGE ELECTRICAL FORM WETTED MATERIALS STEEL & STAINLESS DOUBLE BRAKE Factory Set/Tamperproof Pressure Switches FIXED SET-POINT RANGE ELECTRICAL FORM WETTED MATERIAL Pharmaceutical/Biochem ADJUSTABLE SET-POINT RANGE WETTED MATERIAL ELECTRICAL FORM

Conventional Pressure Switch Design Constant Rate Spring A constant rate type pressure switch, i.e., a bellows, diaphragm, bourdon tube and spring loaded piston, are linear devices—for a certain pressure change the pressure element moves a given distance. For additional movement more pressure (force) is applied. The position of the electrical switch, therefore, influences and/or dictates the pressure switch set point. SPRING LOADED PISTON BOURDON TUBE Disadvantages of the “Constant Rate” Switches NON-STABLE SET POINTS - “Requires Constant Recalibration” BECAUSE: • Sensor mechanism follows the...

Neo-Dyn Pressure Switch Design Nega-Rate® Belleville Spring A negative rate type pressure switch (i.e., a Belleville spring) is a snap acting device. At a certain pressure (apex of the spring curve) the spring snaps over center. At this point, it takes less pressure (force) to continue its movement. The pressure switch set point is a function of the Belleville spring. The electrical switch is in a fixed position and is synchronized to the movement of the Belleville. Advantages of the Nega-Rate® Belleville Disc Spring Switches STABLE SET POINTS - “Eliminates Constant Recalibration” BECAUSE: •...

Neo-Dyn® Pressure, Flow & Temperature Switch Definitions & Terminology Introduction The following definitions and terminology describe the operating characteristics, specifications and other details relative to pressure, flow, and temperature switches. We hope this data provides the answers to questions which may arise and helps you in selecting a switch. Types of Switches ABSOLUTE PRESSURE SWITCH: A switch that compares the pressure being sensed to that of a perfect vacuum. Construction requires the reference chamber to be evacuated. DIFFERENTIAL PRESSURE SWITCH: A switch having both a high...

Electrical Switching Element - The electrical switching element opens or closes an electrical circuit in response to movement by the pressure/temperature sensor. Most Neo-Dyn® products are available in SPST, SPDT and DPDT. Enclosure (Housing) - That part of the instrument which, in varying degrees, protects the mechanism from ambient conditions. Explosion Proof - An enclosure which is capable of withstanding an explosion which may occur within, and capable of preventing the ignition of an explosive atmosphere which may surround it. Gauge Pressure - Gauge pressure is the difference between atmospheric...

Media Compatibility Information The following is a chart of common media with recommended O-Ring compounds that can be used with the Polyimide and Elastomer diaphragms used in Neo-Dyn® pressure switches except as noted. NOTE: The information given on this chart is typical performance data for "Kapton” Type H and Type F films; it is not intended to be used as design data. We believe this Information is the best currently available on the subject. It is offered as a possible helpful suggestion in experimentation you may care to undertake along these lines. It is subject to revision as additional...

Pressure Conversion Formulas INTO %o MULTIPLY BY TO CONVERT "The use of ITT Industrial Controls pressure, Note: It is buyer's responsibility to determine the temperature and flow switches must be in suitability of the Neo-Dyn® switch for its application. ITT accordance with the provisions of the National Industrial Controls makes no warranties and assumes Electric Code, U.L. and/or other local, military or industry standards no liability as to the suitability or sufficiency for buyer's application of that are pertinent to the particular end use. Installation or use not in the switch. Enclosure...