Dear Client,
At SESCO, we recognize that safe and efficient tank operation depends on components that consistently perform under demanding conditions. In this update, we highlight a critical element that often operates quietly in the background: pressure and vacuum hatches, designed to support reliable tank protection, operational safety, and performance.
Performance is not defined by appearance alone, but by whether operating values remain within specification under real working conditions.
As outside temperatures rise and tank cycles intensify, several patterns are commonly observed in the field:
✅ Set pressures drifting outside tolerance
✅ Seal wear leading to vapor loss
✅ Hinges and seating surfaces degrading under repeated use
✅ Increased opening frequency on thief hatches during operations
These conditions typically develop over time during daily operation and repeated cycling, where mechanical performance is continuously exposed to changing temperatures, pressure fluctuations, and operational handling.
WHERE ISSUES START
Across systems from Emerson (Enardo), LaMOT, Jayco and Blaylock Tank Protection, failure patterns are consistent:
Incorrect pressure and vacuum settings relative to operating conditions
✅ Micro-leakage caused by worn or contaminated sealing surfaces
✅ Improper reseating after manual gauging
✅ Material fatigue under cyclic pressure loads
The result is rarely an immediate failure. Instead, performance gradually declines, leading to product loss, emissions and operational inefficiencies.
WHAT WE SEE IN THE MARKET
Most issues are not caused by incorrect product selection, but by operational and supply chain factors:
✅ Delayed replacement cycles
✅ Lack of stock at critical moments
✅ Mixing specifications across multiple suppliers
✅ Using “close enough” alternatives under time pressure
These factors increase the risk of downtime, emissions and repeated maintenance interventions. Preventive action remains the most effective way to maintain system integrity.
THE SESCO APPROACH
At Sesco Industry, the focus is on ensuring that the correct hatch solutions are available with consistent specifications and reliable delivery.
See the complete range of available manhole hatches here:
A traditional thief hatch design engineered for reliable operation and consistent sealing performance during manual tank gauging. The Model 1320 features an integrated pressure and vacuum relief mechanism housed within the cover and is configured with a 69,0 mbar pressure setting and 1,7 mbar vacuum setting. Designed for sweet service applications with a standard 8” API flange, the Model 1320 series is available in multiple pressure configurations ranging from 17,2 up to 69,0 mbar to support varying operational requirements.
A spring-loaded pressure relief valve designed for reliable pressure and vacuum protection during continuous tank operation. The Model 960 combines spring loaded pressure relief with weight loaded vacuum protection and is configured with a 138 mbar pressure setting and 135,8 mbar vacuum setting. Featuring a durable aluminum housing, stainless steel hardware and high-performance sealing materials, the valve supports stable operating performance and controlled venting under varying process conditions
A pressure relief hatch designed for controlled venting performance and reliable tank protection under continuous operating conditions. The Model 951 is configured with a pressure setting of 135,8 mbar and features a 4” inlet connection with 150 FF mounting configuration. Constructed with an aluminum housing, steel hardware and high-performance PPS and FEP sealing materials, the hatch supports stable sealing characteristics and consistent operational performance across demanding storage applications.
A range of aluminum manhole hatches is available for tank access and inspection applications where reliable sealing and durable construction are required. Available configurations include the 4″ Model 211769 with a body diameter of 170 mm and base diameter of 180 mm, as well as 6” manhole versions with sizing from 225 mm up to 240 mm. These models are designed as manhole access hatches and not as pressure relief hatches.
ALIGN YOUR SETUP
Ensuring that hatches operate within specification is not only a maintenance task, but a requirement for safe and efficient tank operations.
For technical consultation or product selection, requests can be submitted via the website contact page.
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