Pressure Gauges​

A pressure gauge, sometimes called a pressure gage, is most widely understood as a mechanical instrument that is used to measure and monitor the pressure of air, gases or fluids in process, commercial and industrial systems. Mechanical pressure gauges operate using the system’s process, meaning they will give you a reading even when you have no power source. Rosemount Pressure Gauges use Emerson’s industry-proven sensor technology, designed to increase safety and reliability by resisting common mechanical pressure gauge failures.

The most common basic mechanical pressure gauge construction depends on a curved bourdon tube mechanism where pressure causes the tube to straighten in proportion to the pressure level. This movement gets conveyed via a small gear train to make a needle move in response, indicating the value on a scale. The design, versatility and durability of a Rosemount Wireless Pressure Gauge and Smart Pressure Gauge make these a better choice in many demanding applications.​

When reliable pressure monitoring is needed in demanding applications, digital pressure gauges are often the wiser choice, and the Rosemount Wireless Pressure Gauge and Smart Pressure Gauge provide the required ability to deliver reliable information, with safer operation and the option for communication via WirelessHART protocol.​

Rosemount Pressure Gauges are available in two versions, with and without WirelessHART® protocol, designated as the Rosemount Wireless Pressure Gauge and Rosemount Smart Pressure Gauge, respectively. The difference is that the Smart Pressure Gauge is intended to serve as a local reading only, and the Wireless Pressure Gauge offers the capability of WirelessHART communication that can be monitored with a wireless gateway.

These two pressure gauge types can be completely customized depending on your application requirements. The faceplate can be specified with several measurement types such as gage, absolute, mirror, compound and vacuum. We also offer assembly options to a diaphragm seal to expand application demands as well as to a manifold.​

ASME B40.1 (Pressure Digital Indicating Gauges) and ASME B40.7 (Pressure Indicating Dial Type) provide several accuracy levels directly related to digital and mechanical pressure gauges ranging from ±0.05%, to ±5% of span or reading. The Rosemount WPG & SPG fit within the 2A (process gauge) ASME B40.7 and B40.1 Accuracy Grade providing ±0.5% of span.​

Here is a typical calibration procedure for a mechanical pressure gauge: If necessary, the technician will open the case, and then make careful adjustments to correct various conditions. Where required, corrections must be made by trial-and-error adjustment of setscrews, and possibly even by bending links slightly. The procedure, including any adjustments made, must be written down on the pressure gauge’s maintenance and calibration record. At some prescribed time interval, the process must be performed again.

If the pressure gauge is well constructed and the technician is experienced, the process works and the unit can be put back into its application, but the calibration process is very time consuming. This procedure is built upon two assumptions. First, pressure gauges invariably require calibration and tweaking to ensure best performance, even brand new from the factory. Second, having a technician performing such a procedure and adjusting improves performance. Both assumptions are becoming obsolete as electronic pressure gauges are becoming more common and skilled technicians are scarcer.​

A Rosemount Pressure Gauge has the same appearance and behavior as mechanical versions, however, it has no bourdon tube and no complex internal mechanism. The bourdon tube is replaced with an electronic sensor, more like an electronic pressure transmitter. The needle moves over the scale driven by a stepper motor in response to an internal electronic mechanism sensing pressure changes. This sensor design is resistant to drift, so calibration intervals can be far longer than with comparable mechanical units, without risk of accuracy loss.​

The Rosemount Pressure Gauges provide up to 10 years of maintenance free operation. The installation conditions and the user configured update rate may impact the standard 10 year battery life. Outside of the battery life of the device, these advanced digital pressure gauges resist failures caused by vibration, corrosion, overpressure and extreme temperatures. The robust design allows for a burst pressure rating of at least 11,000 psi, 150 times overpressure protection, 5G vibration rating, and two barriers of isolation to keep the process in the pipe where it belongs. Plus, the pressure gauge health is monitored with a local status indication light and there is a WirelessHART protocol offering as well.​

Electronic pressure gauges provide real-time pressure readings, enabling operators to monitor and control systems, ensuring safe and efficient operation by managing issues like overpressure events, process leaks and equipment damage. The improved Rosemount Pressure Gauge design reduces the risk of costly process downtime and serious safety incidents that put personnel at risk. The Rosemount Wireless Pressure Gauge specifically can bring measurements into a wireless gateway through WirelessHART protocol to help eliminate the need for operator rounds and deliver trustworthy pressure readings.

A traditional bourdon tube mechanical pressure gauge typically gets installed with a threaded connection. The mechanical nature of traditional pressure gauges introduces several points of failure that can lead to significant safety concerns. The Rosemount Pressure Gauge gets installed the same way, but with a broad offering of assembly options such as a diaphragm seal or instrument manifold, as well as the potential for WirelessHART protocol. Several functions and configuration changes can be made through AMS device manager and connection with a communication device or HART modem. Emerson offers a detailed manual and quick installation guide to properly use Rosemount Wireless Pressure Gauge or Smart Pressure Gauge.​