How do I measure and monitor pressure in my process system?

Measuring process pressure starts with choosing between local indication and remote monitoring. A pressure gauge gives you a visual reading right at the point of measurement — ideal for operator rounds, maintenance checks, and quick local verification. If the pressure data needs to go to a PLC, DCS, or SCADA system for trending, alarming, or closed-loop control, you need a pressure transmitter that converts the measurement into a standard 4–20 mA or digital signal. Many installations use both — a gauge for local visibility and a transmitter for the control system. Pressure switches provide a discrete on/off output when pressure crosses a set threshold, used for high-pressure alarms and safety shutdowns. For corrosive, viscous, or high-temperature media that would damage a standard sensor, a diaphragm seal isolates the instrument with a flexible membrane and fill fluid. Accessories like snubbers (to dampen pulsation from pumps and compressors) and siphons (to protect gauges from live steam) extend instrument life and improve accuracy in challenging conditions.

What is the difference between a pressure gauge and a pressure transmitter?

A pressure gauge is a local, visual indicator — it displays the current pressure on a dial or digital screen at the point where it is installed. Gauges are used for operator rounds, maintenance checks, and local process verification. They do not send a signal to the control system. A pressure transmitter converts the measured pressure into a standard electrical signal (typically 4–20 mA) that is sent to a PLC, DCS, or SCADA system for monitoring, trending, alarming, and control. Transmitters enable remote pressure monitoring and closed-loop pressure control without requiring an operator to be physically present at the gauge. Many installations include both — a gauge for local visual indication and a transmitter for remote monitoring and control. When selecting between them, consider whether the pressure data needs to be available only locally (gauge) or integrated into the plant control system (transmitter, or both).

What is a diaphragm seal and when is it needed?

A diaphragm seal (also called a chemical seal or remote seal) is a flexible membrane that isolates the pressure-sensing element of a gauge or transmitter from direct contact with the process media. The space between the diaphragm and the instrument is filled with a compatible fill fluid (typically silicone oil or fluorinated fluid) that transmits the process pressure to the instrument's sensing element hydraulically. Diaphragm seals are needed when the process media would damage, clog, or contaminate a standard instrument — corrosive chemicals, viscous fluids, slurries, hot media that would damage the sensor, sanitary/food-grade applications requiring cleanable surfaces, or media that solidify or crystallize in instrument cavities. They are also used when the process temperature exceeds the instrument's rating — the diaphragm seal acts as a thermal barrier. Seals are available in a wide range of materials (316SS, Hastelloy, tantalum, PTFE-lined) and mounting configurations (direct mount, remote mount with capillary tubing).

How do I select the correct pressure gauge range for my application?

The gauge range should be selected so that the normal operating pressure falls in the middle third of the dial — between 25% and 75% of the full-scale range. This ensures accurate reading under normal conditions while providing headroom for pressure spikes without pegging the pointer. For example, if the normal operating pressure is 60 psi, a gauge with a range of 0–100 psi or 0–150 psi is appropriate — not 0–60 psi (too close to full scale, no headroom) or 0–300 psi (operating point is in the bottom 20% of the scale, reducing readability). ASME B40.100 recommends that the maximum operating pressure not exceed 75% of the gauge's full-scale range for steady pressure service, and 65% for fluctuating pressure service. Also consider the gauge's accuracy class, dial size (larger dials for better readability), connection size and type (NPT, socket weld), case material, wetted material compatibility, and whether a liquid-filled case is needed for vibration damping.

What are pressure gauge snubbers and siphons, and when are they needed?

Snubbers and siphons are protective accessories installed between the process and the pressure gauge to extend gauge life and accuracy. A snubber (also called a pulsation dampener or restrictor) contains a small orifice or porous element that restricts the flow of media into the gauge, damping out rapid pressure pulsations from pumps, compressors, or reciprocating equipment. Without a snubber, the gauge pointer oscillates rapidly, making reading impossible and wearing out the gauge mechanism prematurely. A siphon (pigtail siphon) is a U-shaped or coiled tube installed between a steam line and the gauge — it traps a column of condensed water that prevents live steam from reaching the gauge's Bourdon tube. Steam temperature would damage the gauge's internal mechanism; the water column transmits the pressure while keeping the gauge at a safe temperature. Use a snubber whenever the process pressure pulsates or fluctuates rapidly, and use a siphon whenever measuring steam or high-temperature vapors.

Pressure Control - WIKA

Pressure control products measure, monitor and regulate pressure in liquids, gases and steam. Accurate pressure control protects equipment and keeps processes stable.

Pressure Control Products

Categories from WIKA (14)

Industrial Gauges

Industrial pressure gauges are built for the vibration, pulsation and rough handling found in plants, pump rooms and machinery. They give operators a dependable local reading of pressure in water, air, oil, steam and process lines.

Industrial Gauge Options

Stainless steel cases – corrosion resistance and durability
Liquid-filled gauges – dampen vibration and pulsation for steady readings
Brass and stainless internals – match media compatibility
Bottom and back connections – for line and panel mounting
Dial sizes from 2" to 6" – readable at a distance

Selecting a Gauge

Choose a range so normal operating pressure sits in the middle of the dial, generally about twice the operating pressure. Use a liquid-filled gauge on pumps and compressors, and add a snubber for pressure spikes. Confirm the connection size and accuracy grade.

Centro carries industrial pressure gauges for plant, process and equipment applications.

Process Gauges

Process pressure gauges are built for chemical, petrochemical, refining and power plant service. Heavy-duty cases, stainless wetted parts and high accuracy give dependable readings in demanding environments.

Process Gauge Features

Solid-front safety cases – operator protection
316 stainless steel internals – corrosive media
Liquid filling – vibration and pulsation damping
Accuracy to 0.5% – precise readings
4.5" and 6" dials – easy reading

Choosing a Process Gauge

Choose range, accuracy, connection and materials suited to the process. Add diaphragm seals for corrosive, viscous or high-temperature media.

Centro supplies process gauges and accessories for plant instrumentation.

Pressure Transmitters

Pressure transmitters send accurate pressure readings to your control system over long distances. They're the standard instrument for process monitoring, control loops and safety systems.

Transmitter Types

Gauge and absolute transmitters – line pressure measurement
Differential pressure transmitters – flow, level and filter monitoring
Smart transmitters – HART and digital communication
Remote seal transmitters – hot, viscous or corrosive media
Hazardous area models – explosion-proof and intrinsically safe

Choosing a Transmitter

Select range, accuracy, process connection and wetted materials. Consider output, display and approvals. Manifolds simplify installation and calibration.

Centro supplies pressure transmitters and manifolds for process measurement.

Related categories: Pressure Control | Pressure Regulators | Pressure Switch | Sequence Valves | Gauges

Commercial Gauges

Commercial pressure gauges cover HVAC, plumbing, fire protection and general building services. They're economical, easy to read and available in many standard ranges.

Commercial Gauge Options

Dry and liquid-filled gauges – general service
Brass internals – water, air and oil
Common dial sizes – 2" to 4"
Bottom and back connections – line or panel mounting
Fire protection gauges – sprinkler system ratings

Choosing a Gauge

Select a range about twice normal operating pressure, and match connection size and dial type. Liquid-filled gauges handle vibration from pumps.

Centro supplies commercial gauges for HVAC, plumbing and building systems.

Pressure Gauges

Pressure gauges are instruments used to measure the pressure of fluids or gases in various industrial, commercial, and residential applications. They visually indicate the pressure levels, allowing operators to monitor and control processes effectively. Pressure gauges consist of a dial or digital display with a needle or numeric readout representing the pressure measurement in units such as PSI (pounds per square inch) or kPa (kilopascals). They typically feature a Bourdon tube, diaphragm, or other sensing elements that convert the applied pressure into a mechanical displacement, which is then displayed on the gauge. Pressure gauges are available in different types, including analog and digital, with varying accuracy levels and pressure ranges to suit specific application requirements. They are commonly used in oil and gas, manufacturing, HVAC, and automotive industries, where pressure monitoring is critical for operational safety, system performance, and quality control. Pressure gauges provide valuable feedback for adjusting process parameters, detecting leaks or anomalies, and ensuring the optimal functioning of equipment and systems.

Related categories: Gauges | Gauge Parts & Accessories | Manometers | Tridicators

Differential Pressure Gauges

Differential pressure gauges measure the difference between two pressure points. They show filter loading, flow through orifices, level in pressurized tanks and pressure drop across equipment.

DP Gauge Options

Diaphragm DP gauges – low differential ranges
Piston DP gauges – high line pressures
DP gauges with switches – alarms and control
Backflow test kits – backflow preventer testing
Accessories – manifolds and mounting kits

Choosing a DP Gauge

Specify differential range, maximum line pressure, wetted materials and connection. Use 3-valve manifolds to protect gauges during startup.

Centro supplies differential pressure gauges and accessories.

Shop by type: Backflow Test Kits | Differential Pressure Gauge Accessories

Related categories: Pressure Gauges | Digital Gauges | Test Gauges | Commercial Gauges | Process Gauges

Differential Pressure Control

Differential pressure liquid control products are essential components used in various applications to monitor and control the pressure difference between two points in a liquid system. These products are designed to measure the pressure drop across filters, pumps, valves, or other flow control devices. They are crucial in maintaining proper flow rates, preventing system damage, and ensuring optimal performance. Differential pressure liquid control products typically consist of a differential pressure transmitter or sensor, a flow element (such as an orifice plate, venturi tube, or flow nozzle), and associated piping and instrumentation. The transmitter or sensor detects the pressure difference and converts it into a proportional electrical signal, which can be used for monitoring, control, or alarm. These control products find applications in oil and gas, chemical processing, water and wastewater treatment, and HVAC systems. They help optimize system efficiency, improve process control, and ensure liquid systems' safe and reliable operation by providing accurate and real-time differential pressure measurements.

Related categories: Liquid Level | Level Switches | Radar | Level Sensors | Float Switch

Pressure Snubber

Pressure snubbers smooth out pressure spikes and pulsations before they reach gauges, switches and transmitters. Damping the surges gives steadier readings and helps instruments last longer, especially near pumps, compressors and quick-closing valves.

Snubber Types

Porous metal disc snubbers – sintered elements for gases and light liquids
Piston snubbers – self-cleaning action for dirtier fluids
Adjustable snubbers – tune the damping to your system
Brass and stainless steel – match media compatibility

Choosing a Snubber

Select the element grade based on fluid viscosity: finer discs for air and water, coarser for oils. Match thread sizes to your gauge and process connection. For very severe pulsation, combine a snubber with a liquid-filled gauge.

Centro carries pressure snubbers and gauge accessories to protect your instruments.

Related categories: Pressure Control Accessories | Manifold Valves | Gauge Cock Valve | Instrument Valve | Syphons

Pressure Control Accessories

Pressure control accessories protect instruments, simplify maintenance and make pressure measurements more accurate. Syphons, snubbers, manifolds and valves are essential to a dependable gauge or transmitter installation.

Accessories Available

Pressure snubbers – dampen pulsation and spikes
Syphons – protect gauges from live steam
Manifold valves – isolate and equalize transmitters
Gauge cock and instrument valves – isolate instruments for service
PT plugs – quick test ports for pressure and temperature checks

Building an Installation

A typical gauge installation includes an isolation valve, a protection device (snubber or syphon) and the gauge itself. Choose materials compatible with the media and pressure ratings above system maximum.

Centro carries pressure control accessories to complete and protect your instrument installations.

Related categories: Pressure Control | Gauges | Pressure Transducers | Pressure Switch | Pressure Transmitters

Gauges

We offer pressure gauges, vital instruments that measure and indicate fluid or gas pressure within a system. These gauges are commonly employed in various industries, including manufacturing, oil and gas, automotive, and HVAC systems. Pressure gauges consist of a dial or digital display that shows the pressure reading and a sensing element that detects the pressure and converts it into a readable form. They come in different types, such as Bourdon tube gauges, diaphragm gauges, and digital pressure gauges, each suited for specific applications and pressure ranges. Pressure gauges provide crucial information for monitoring and controlling processes, ensuring optimal performance and safety. They enable operators to gauge system pressure levels, detect abnormalities, and make informed decisions regarding system adjustments or maintenance. Pressure gauges may also incorporate features such as maximum pressure indicators, adjustable pointers, or alarms for added functionality. With their accuracy, reliability, and ease of use, pressure gauges are crucial in maintaining operational efficiency and safety in various industries.

Shop by type: Boiler Gauges | Manometers | Pressure Gauges | Gauge Parts & Accessories | Tridicators

Manifold Valves

Instrument manifold valves mount between process piping and pressure or differential pressure transmitters. A manifold lets technicians isolate, equalize, vent and calibrate instruments without shutting down the process.

Manifold Types

2-valve manifolds – isolate and vent gauge and pressure transmitters
3-valve manifolds – isolate and equalize DP transmitters
5-valve manifolds – add vent and calibration ports for DP service
Direct-mount and remote-mount – fit your transmitter installation
Stainless and alloy bodies – for corrosive and high-pressure service

Choosing a Manifold

Match the manifold to the transmitter type and connection (flanged or NPT), and the process pressure and temperature. Choose hard or soft seats according to temperature and leak-tightness requirements. Integrated manifolds save space and leak points.

Centro supplies instrument manifold valves for pressure and DP transmitter installations.

Related categories: Pressure Control Accessories | Gauge Cock Valve | Pressure Snubber | Instrument Valve | Syphons

Gauge Cock Valve

Gauge cock valves isolate pressure gauges, switches and transmitters from the process so they can be removed, replaced or calibrated without shutting down the line. They're a small, inexpensive part that saves a lot of time.

Gauge Cock Options

Tee handle and lever handle – quick quarter-turn operation
Brass, carbon steel and stainless – match media and environment
Male and female NPT connections – fit common gauge installations
Bleed and vent options – safely relieve trapped pressure
Needle-style gauge valves – higher pressure service

Choosing a Valve

Select the material, pressure rating and connection size for your gauge and process. On steam, use a syphon between the gauge cock and gauge. Bleed valves make gauge removal safer.

Centro carries gauge cock valves and pressure accessories for instrument installations.

Related categories: Pressure Control Accessories | Instrument Valve | Manifold Valves | Syphons | Pressure Snubber

Syphons

A syphon is a simple yet effective tube-shaped device that consists of two legs bent in a U-shape. The purpose of the syphon is to transfer liquid from a higher container or location to a lower one without the need for any external pumping or suction. One leg of the syphon is inserted into the higher container or source of liquid, while the other leg is placed into the lower container. The liquid in the higher container initially fills the syphon's legs, creating a continuous flow due to the difference in pressure between the two ends. Gravity then causes the liquid to flow through the syphon, moving from the higher to the lower container. Syphons are commonly used in various applications, including laboratory experiments, aquariums, irrigation systems, and fluid transfers in industrial processes. They provide a simple and efficient means of transferring liquids over a vertical or horizontal distance without the need for complex pumps or mechanical devices.

Instrument Valve Accessories

Instrument valve accessories complete instrument installations with handles, mounting brackets, plugs, caps and fittings that keep valves secure and serviceable.

Accessories Available

Replacement handles – standard and color-coded
Mounting brackets – panel and pipe mounting
Plugs and caps – seal unused ports
Locking devices – prevent unauthorized operation
Fittings and adapters – connect tubing and pipe

Choosing Accessories

Match accessories to your valve series and connection types. Color-coded handles help identify functions.

Centro supplies instrument valve accessories.

Related categories: Pressure Control Accessories | PT Plugs | Syphons | Instrument Valve | Gauge Cock Valve

Filter

In Stock Only

Filter

3,734 items

Sort by:

content loaded

Compare

Pressure Control - WIKA

Pressure Control Products

Industrial Gauge Options

Selecting a Gauge

Process Gauge Features

Choosing a Process Gauge

Transmitter Types

Choosing a Transmitter

Commercial Gauge Options

Choosing a Gauge

DP Gauge Options

Choosing a DP Gauge

Snubber Types

Choosing a Snubber

Accessories Available

Building an Installation

Manifold Types

Choosing a Manifold

Gauge Cock Options

Choosing a Valve

Accessories Available

Choosing Accessories

Orders & purchases

Divisions