Industrial and OEM Pressure Switches by NOSHOK

A pressure switch is a device that detects the presence of fluid pressure. Pressure switches use various sensing elements such as diaphragms, bellows, bourdon tubes, or pistons. The movement of these sensors, caused by pressure fluctuation, is transferred to a set of electrical contacts to open or close a circuit.

When selecting pressure switches, you must consider several critical criteria:

• The electrical requirements (volts, amps, AC, or DC)
• The area classification (hazardous, non-hazardous, general-purpose, water-tight)
• The pressure sensing range
• The body materials exposed to ambient contaminants
• The wetted materials - parts exposed to the process media

Typical applications for mechanical pressure switches include hydraulics & pneumatics, pumps & compressors, tank monitoring, leak detection, and water management.

NOSHOK's new mechanical pressure switch program addresses a broader range of applications. It offers a significantly expanded selection of process and electrical connection options, including spade terminals, Hirschmann, Packard, Deutsch, M12 x 3-pin, flying leads, terminal screws, and both Weatherpack Tower and Weatherpack Shroud. Each of the four new NOSHOK switch series offers vacuum, low pressure, and high-pressure versions and is CE compliant for RFI, EMI, ESD suppression, and RoHS compliance.

The NOSHOK 100 Series Mechanical Compact SPST Pressure Switch has been updated with a creep action, low current switch. These switches have silver-plated contacts with switch adjustment ranges ranging from vacuum to 6,000 psi. The 100 Series switch series includes housing materials such as brass and zinc-nickel and wetted parts made of Buna-N or Kapton, depending on the model.

NOSHOK’s new 200 Series Mechanical Compact SPDT Pressure Switch is an SPST or SPDT snap-action switch with solid Silver contacts. This switch ranges from vacuum through 6,000 PSIG and Brass or Zinc-nickel housing material with Buna-N diaphragm wetted parts.

The new 300 Series Mechanical Compact SPDT with Adjustable Hysteresis Pressure Switch is an SPST or SPDT snap-action switch with solid Silver contacts. The 300 Series offers switch adjustment ranges from vacuum through 4,600 PSIG depending on model and a standard Zinc-nickel housing with Buna-N diaphragm wetted parts. The NOSHOK 300 Series switch provides an improved contact rating over the previous version of 6A 125V/250VAC and 6A 12/24VDC.

Lastly, NOSHOK’s new 400 Series Mechanical Heavy-Duty Pressure Switch is a snap-action, high current device that offers field adjustability. The 400 Series offers switch adjustment ranges from vacuum through 4,600 PSIG with a Standard Zinc-nickel with Buna-N diaphragm wetted parts. This switch also provides an improved contact rating over the previous version of 6A 125V/250VAC and 6A 12/24VDC.

For more information, contact Advance Instruments. Call them now at (888) 388-6446 or visit their website at https://advanceinstruments.com.

Manifold Valves in Flow Measurement

Several approaches to measuring and controlling flow in process applications have been established over the years by the industry. Magnetic flow meters, Coriolis flowmeters, vortex meters, thermal dispersion flow meters, and a wide range of differential sensing primary elements are some examples that have successfully evolved over the years. 

Installing a differential sensing system to produce the pressure drop is one of the oldest methods of calculating flow. The orifice plate is still widely used in this process. Wedge meters, pitot meters, VENTURI meters, cone style meters, and other differential producing devices are examples. 

Many experienced industry experts would inform us that there is no one-size-fits-all solution when it comes to flow calculation. The process itself and economics and performance expectations all play a role in determining the best method to use. 

The user must be aware of the following while using the DP method to measure flow accurately.

• The specific gravity or density of the fluid under consideration. 
• Chemical compatibility of the media with the materials used. 
• The estimated minimum and maximum flow rates. 
• The media's static pressure and temperature (particularly in gas measurement applications). 
• The inside diameter of the tubing. 
• The primary element's parameters (in the case of the orifice plate, the bore dimension and bore location within the plate). 
• The user must examine the pipe's flow profile to ensure that sufficient fully formed turbulent flow to obtain an accurate measurement (Reynolds number calculations come into play, and piping conditions in the process should be analyzed upstream and downstream). 
• What amount of differential pressure does the consumer want to generate? 
• Is the generated DP compatible with the flow device or transmitter? 
• How much pressure drop in the flow stream is acceptable?

So, where do manifold valve products fit in, and why are they so crucial? For the most part, the valves are service valves between the primary meter and the measuring instrument (DP transmitter or flow computer). The valves allow the user to block in, calibrate or check calibration, replace instruments, and vent entrapped pressure without shutting down the critical operation.

Manifold Valves are available in several configurations, soft seat, hard seat, 2-valve types, 3-valve types, or 5-valve types. They are available in various materials, but stainless steel and carbon steel are the most common. These valves come with a standard bore or large bore design for custody transfer applications. Manifold valves offer high and low-pressure isolation (pressure upstream and downstream of the differential producing element) and the ability to equalize the differential pressure to the transmitter or flow computer.  Finally, manifold valves can offer a dedicated vent valve to vent entrapped pressure during service operations.

In conclusion, manifold valves play a critical role in allowing the user to operate and service instrumentation in their processes safely. Every application and every supplier's goal is to work collaboratively to achieve safety, protect valuable assets, reduce downtime during maintenance, lower maintenance cost, and higher measurement accuracy.

For more information, contact Advance Instruments. Call them at (888) 388-6446 or visit https://advanceinstruments.com.

Diaphragm Seals Thermal Error Calculations

Measuring errors based on ambient conditions and the diaphragm seals' fill physical properties cause temperature-related errors when connected to pressure, absolute pressure, or level transmitters.

Three major factors contribute to thermal error:

• Type of fill fluid used
• Fill fluid volume
• Diaphragm flexibility

The choice of fill fluid contributes directly to thermal  errors in proportion to the coefficient of thermal expansion of the  fluid. The resulting internal pressures produce adverse forces on the diaphragm which in turn are reflected in the pressure instrument.

DOWNLOAD THE NOSHOK DIAPHRAGM SEALS THERMAL ERROR CALCULATIONS SHEET HERE

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(888) 388-6446
www.advanceinstruments.com

All-in-One Non-Metallic Diaphragm Seal with Pressure Transmitter/Switch

NOSHOK is a high-quality manufacturer of pressure, level, temperature, force measurement instruments, needle and manifold valves transducers, transmitters, gauges, and valves.

NOSHOK is introducing it's new electronic indicating pressure transmitter with two alarms, protected by a corrosion-resistant, chemically inert PTFE diaphragm seal with a single pressure connection.

The device is ideal for water, wastewater & chemical feed applications and is a tested and proven solution used in many municipalities. In many situations, it replaces the heavy analog gauge with a diaphragm seal and mechanical switch, commonly used for pump shut-off protection. It offers fewer possible leak paths, no moving parts, and a high level of repeatability, durability, compact size, and lightweight.

For more information, contact Advance Instruments. Call them now at (888) 388-6446 or visit their website at https://advanceinstruments.com.

Versatile Panel Meters and Digital Indicators for Any Process Variable

NOSHOK Digital Indicators provide local indication for pressure, level, and temperature transmitters. The NOSHOK Attachable Loop-Powered Digital Indicators fit easily to NOSHOK pressure transmitters utilizing a 4 to 20 mA output signal and the Hirschmann (DIN 43650A) connector. NOSHOK also offers a dual display model that accepts a wide variety of input signals, including thermocouples or RTDs, current, voltage, resistance, and process signals. Plug-in option cards are available on several models for field upgrading.

DOWNLOAD THE NOSHOK DIGITAL INDICATOR SOLUTIONS CATALOG HERE

For more information on NOSHOK products in Western Pennsylvania, Western Maryland, Ohio, and West Virginia contact Advance Instruments. Call them at (888) 388-6446 or visit their website at https://advanceinstruments.com.

NOSHOK Measurement Product Catalog

NOSHOK is a manufacturer of pressure, level, and temperature measurement instrumentation for oil and gas, fluid power, automation, chemical processing, manufacturing, water and waste water, food and beverage industries. Products include gauges, transducers, transmitters, switches, thermometers, transmitters, digital indicators, thermos wells, needle valves, manifold valves, and diaphragm seals.

NOSHOK Measurement Solutions Catalog Includes:

• Pressure, Level, Temperature Instruments
• Needle Valves
• Manifold Valves
• Diaphragm Seals
• Digital Indicators 

DOWNLOAD HERE

For more information on NOSHOK products in Western Pennsylvania, Western Maryland, Ohio, and West Virginia contact Advance Instruments. Call them at (888) 388-6446  or visit their website at https://advanceinstruments.com.

Instrument Valves: The Difference Between a Rotating One Piece Stem and a Non-Rotating Two Piece Stem

Process instrument valves are used with devices such as pressure measurement transmitters, gauges, and switches to isolate the device from the process media for replacement, calibration, and maintenance. Instrument valves are combined together and assembled into block and bleed manifolds combing multiple valves into a single body configuration, with each valve having a separate external connection and a common internal connection.

A critical component to the instrument valve is the valve stem. The stem positions the stem point into the orifice and against the valve seat to control flow and to isolate the process.

INSTRUMENT VALVE STEM TYPES

A rotating one piece valve stem rotates and translates along its axis as it is being driven axially into the orifice. The rotational motion of a one piece stem can produce friction as the stem interacts with the seating area, which could result in galling at the seating surface. This is less of an issue in a soft seat valve or if the media provides lubrication.

A non-rotating two piece stem tip rotates independently from the stem and stops rotating as it is driven axially against the orifice sealing surface while the stem continues its rotational and axial movement.

For more information about process instrumentation valves and valve manifolds, contact Advance Instruments. Call them at (888) 388-6446 or visit their web site at https://advanceinstruments.com.

The Top Three Reason Why Pressure Gauges Fail

Industrial pressure gauges (NoShok)

Since the mid-eighteen hundreds, the technology used in today's pressure gages has been around, and the pressure gage is still one of today's most common pressure measurement methods. Today, most pressure gages still include the bourdon tube, socket, and geared motion along with a pointer and dial indicating process pressure.

Because the pressure gage is a purely mechanical device, it is essential to take care of three process circumstances. Temperature, vibration, and pulsation are the three factors that can adversely affect accuracy and performance.

Effects from Temperature

For each 100-degree temperature change from which the gage is calibrated, the user may encounter an extra reading error of up to 2 percent. The cause is the temperature shift in the bourdon tube element's elasticity or spring rate. Although the effects of ambient temperature are difficult to circumvent, we can address the effects of process temperature. In steam service, to dissipate process heat, the common practice is to install coil syphons or pigtail syphons. Another popular practice is to install a capillary diaphragm seal to separate the gage from the source of elevated heat. In the seal and capillary scheme, there are many choices available with fill liquid to withstand temperatures up to 600 degrees F. Many users choose to heat their instrumentation via electric trace or steam trace under severe cold ambient conditions. When choosing and implementing pressure gages, process and ambient temperature is a significant consideration.

Pressure snubbers.

Effects from Vibration

Vibration due to pumps, motors and other rotating equipment may result in excess wear and potential premature failure of the internal working parts of a pressure gage, including the bourdon tube and the movement or gear mechanism. Due to pointer oscillation, vibration also causes difficulties in accurate reading of the gage. Exposure to constant vibration is one of the most prevalent causes of pressure gage failure. Applying and installing a liquid filled pressure gage is the most commonly accepted solution. Either glycerin or silicone is the filling fluid of choice. Liquid-filled case gages not only address pointer oscillation, but also safeguard and lubricate inner geared motion.

Effects from Pulsation

Pulsation of the process can occur around the pump discharge as well as rapid operating

Diaphragm seals.

valves. Many consumers believe that pulsation will be completely addressed by fluid filling a pressure gage. While a liquid-filled case gauge helps to dampen the pulsation effects, this process condition is often not fully addressed. Upstream of the gauge socket, pulsation dampers are mounted and can be a piston-like snubber, a sintered metal snubber, or a threaded in-flow restrictor in the gauge socket. Another common practice for addressing pulsation is a needle valve installed upstream of the gage that is "pinched down" or slightly opened. Because the user could inadvertently open the valve and thereby negate the flow restriction, it is not recommended to rely solely on a needle valve to address pulsation. A threaded orifice / flow restrictor or a sintered metal snubber is the least expensive way to deal with pulsation in clean fluids (gases or clean low viscosity liquids).  A piston snubber is generally mounted in dirtier and greater viscosity liquids.

Conclusion

Three process conditions are temperature, vibration and pulsation that adversely affect a pressure gauge. Being aware of and taking the necessary steps to address these three process conditions can help minimize accuracy errors and add to the pressure gauge's service life.

For more information about the proper application of pressure instrumentation, contact Advance Instruments. by visiting https://advanceinstruments.com or by calling (888) 388-6446.