Core Summary
Ordinary pressure gauge connectors in corrosive media are prone to corrosion and rapid reading drift. After replacing with diaphragm pressure gauges and aligning the diaphragm material with the flange form, the maintenance cycle is significantly extended. This record is based on similar working conditions in a chemical water treatment workshop and does not represent a specific project delivery commitment.
I. On-site Issues
Repeated inaccuracies in ordinary pressure gauges within half a year
The workshop transports weakly acidic circulating water with high chloride ion content. The originally used ordinary Bourdon tube pressure gauge experienced issues such as pointer stagnation and connector leakage within half a year. Upon disassembly, obvious corrosion marks were found on the liquid-receiving threads and the inner wall of the Bourdon tube, resulting in increased resistance in the action mechanism and readings deviating from the true value.
Downtime for gauge replacement affects production line rhythm
Although pressure gauges are not expensive, they are installed in various locations such as high points on pipe racks and deep inside pump rooms. Each replacement requires handling paperwork, removing insulation, draining liquid, and reinstalling. Frequent gauge replacements reduce equipment availability and make the instrument team overwhelmed.
II. Solution and Deployment
Use diaphragm pressure gauges to isolate the medium
It is recommended to use Bailey & Mackey Type 65 / Type 70 diaphragm pressure gauges, which completely separate the measured medium from the gauge movement using an elastic diaphragm. When the diaphragm is deformed under pressure, it transfers the pressure to the gauge head through the filling liquid, preventing the movement from directly contacting corrosive media.
Re-check the diaphragm material based on the medium
Different corrosive media have significantly different erosion rates on diaphragm materials such as 316L, Hastelloy, and tantalum. After providing the supplier with the pH, temperature, and chloride ion concentration of the on-site medium, confirm the material grade of the diaphragm and wetted flange to avoid using generic materials for special media.
Installation method matches the existing pipe orifices
The workshop originally had some pressure gauge interfaces installed directly with threads. Type 65 provides a direct installation method that can reuse existing 1/2" or 3/4" pipe orifices; for some locations where panel readings are required, Type 70 panel installation is used to facilitate direct viewing of the dial during inspections.
III. Results and Value
Significantly Extended Maintenance Cycle
After the diaphragm gauge was put into use, inaccuracies and leaks caused by corrosion were significantly reduced. Under similar operating conditions, the replacement cycle was extended from approximately 6 months to over 18 months, allowing the instrument team to shift their focus to other preventative maintenance tasks.
Reduced Unplanned Downtime
The number of temporary downtimes caused by header failures decreased by approximately 60%. This benefit is difficult to summarize in a single number, but for continuous production workshops, avoiding even one unexpected downtime can mean preventing an entire round of production scheduling adjustments.
Follow-up Recommendations
Diaphragm pressure gauges are not set in stone. It is recommended to inspect the appearance of the diaphragm and the state of the filling fluid every 12 months, and to replace the diaphragm promptly if cracks or bulges are found. The diaphragm is a replaceable consumable, and the cost of spare parts is much lower than replacing the entire gauge.
Parameters Table (Application Reference)
> The above is a reference for similar operating conditions, and the specific effects may vary depending on on-site conditions.
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