Pressure Control - Marsh Bellofram
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
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.
Related categories: Pressure Gauges | Test Gauges | Process Gauges | Differential Pressure Gauges | 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.
Related categories: Pressure Gauges | Process Gauges | Commercial Gauges | Test Gauges | Differential Pressure 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.
Related categories: Pressure Gauges | Commercial Gauges | Industrial Gauges | Test Gauges | Differential Pressure Gauges
Test gauges, also called calibration gauges, provide high-accuracy readings for checking and calibrating other instruments. They're essential tools for maintenance and instrument technicians.
Test Gauge Options
- Analog test gauges – 0.25% accuracy with mirror dials
- Digital test gauges – high accuracy and data logging
- Wide range selections – vacuum to high pressure
- Calibration certificates – traceable documentation
Choosing a Test Gauge
Select accuracy at least four times better than the instruments you're testing. Choose range and connection to match. Handle and store test gauges carefully to protect accuracy.
Centro supplies test gauges for calibration and verification.
Related categories: Pressure Gauges | Differential Pressure Gauges | Commercial Gauges | Digital Gauges | Process Gauges
Gauge parts and accessories protect, mount and maintain pressure gauges. The right accessory improves accuracy and gauge life and makes installations safer.
Accessories Available
- Syphons – protect gauges from steam
- Snubbers – dampen pulsation
- Gauge valves and cocks – isolation for service
- Panel mounting kits and brackets – secure mounting
- Overpressure protectors – prevent damage from spikes
Choosing Accessories
Match thread sizes and materials to your gauge and process, and select protective devices for the conditions.
Centro supplies gauge parts and accessories.
Related categories: Gauges | Tridicators | Pressure Gauges | Manometers
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
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
Related categories: Pressure Control | Pressure Switch | Pressure Control Accessories | Pressure Transmitters | Pressure Transducers
$340.95
Subject to factory lead times
$340.95
Subject to factory lead times
$340.95
Subject to factory lead times
$340.95
Subject to factory lead times
$340.95
Subject to factory lead times
$340.95
Subject to factory lead times
$340.95
Subject to factory lead times
$386.17
Subject to factory lead times
$386.17
Subject to factory lead times
$386.17
Subject to factory lead times
$386.17
Subject to factory lead times
$386.17
Subject to factory lead times
$386.17
Subject to factory lead times
$386.17
Subject to factory lead times
$386.17
Subject to factory lead times
$386.17
Subject to factory lead times
$386.17
Subject to factory lead times
$386.17
Subject to factory lead times
$386.17
Subject to factory lead times
$368.94
Subject to factory lead times
$368.94
Subject to factory lead times
$368.94
Subject to factory lead times
$368.94
Subject to factory lead times
$368.94
Subject to factory lead times
$340.95
Subject to factory lead times
$340.95
Subject to factory lead times
$340.95
Subject to factory lead times
$340.95
Subject to factory lead times
$340.95
Subject to factory lead times
$340.95
Subject to factory lead times
$340.95
Subject to factory lead times
$386.17
Subject to factory lead times
$386.17
Subject to factory lead times
$386.17
Subject to factory lead times
$386.17
Subject to factory lead times
$386.17
Subject to factory lead times
$386.17
Subject to factory lead times
$386.17
Subject to factory lead times
$386.17
Subject to factory lead times
$386.17
Subject to factory lead times
$386.17
Subject to factory lead times
$386.17
Subject to factory lead times
$386.17
Subject to factory lead times
$368.94
Subject to factory lead times
$368.94
Subject to factory lead times
$368.94
Subject to factory lead times
$368.94
Subject to factory lead times
$368.94
Subject to factory lead times
- 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.
- 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).
- 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).
- 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.
- 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.