Thursday, May 31, 2018

Increased cycle count improves operational efficiency in slurry ore mining operations

slurry pipeline
Slurry pipeline.
Challenge
Long distance slurry pipelines for moving mineral concentrates over various elevations and long distances is often more economical than trucking or rail due to topography constraints and environmental concerns. To capitalize on these investments, the pipe sizes are maximized. Therefore, large-bore dependable valves are vital to the success of the slurry pipelines.

Three months after the main choke and choke loop press letdown stations were commissioned at a large copper-gold-molybdenum mining operation, ongoing repairs were required for all eight competitor valves. Valves in this position were expected to perform for at least 180 cycles without repair. These failures and leakage problems were caused by the valves’ integral seat design, which form a gap between the ball and seat allowing particles to enter the sealing area in the reverse pressure. This problem cost this customer an average of $800,000 to $1M per year in maintenance repairs.

Solution
MOGAS valve
After one year the
MOGAS valve performed 818
successful cycles—over four times the cycle
count required in this application.
Even with MOGAS’ 40-year history of successfully engineering large valves for the slurry transport market, MOGAS proposed to lease a test valve to be placed alongside a series of competitor valves.
In January 2013, a 36-inch, ASME 300 Class model CST-1 valve was installed in the first loop of the control station. In this model’s proven bi-directional seat design, the seat maintains 100% contact with the ball in both normal and reverse pressures. This prevents build-up behind the downstream seat and ensures evacuation of solids around upstream seat during cycling.


Results
Under the same process conditions,
the competitor’s valve underperformed and
required frequent maintenance due to erosion.
One year later during decommission, the MOGAS valve was inspected. It had performed 818 cycles; far more than the 180 cycle count required in this application. The MOGAS valve was then removed and installed outside the loop, in the main choke station replacing the competitor valve, where it further performed 215 cycles for the next two years.

After three years of continuous operation, the MOGAS valve had successfully performed 1033 cycles. On inspection, the ball and seat were in good repair, so only the gasket and packing box were replaced and the valve was put back in to service.

Advantages to installing a MOGAS valve:
  • No downtime due to increased cycle time and continuous operation 
  • No repair or maintenance of ball and seat
  • Increased cycle count and greater revenue
For more information, contact CTi Controltech by calling 925-208-4250 or visit https://cti-ct.com.

Reprinted with permission from MOGAS.

Wednesday, May 23, 2018

Welcome to CTi Controltech

Since 1976 CTi Controltech has represented the leading process control and combustion manufacturers.  These products, together with our engineering capabilities, give CTi customers high quality solutions to the most difficult industrial applications.

CTi is focused on the top quality manufacturers in process control, valves, instrumentation, and combustion. Over the past three decades CTi has continually added and upgraded the quality of companies it represents.

Our staff of engineers and technicians is well versed with all our products and are ready to help you with your most demanding applications.

Wednesday, May 9, 2018

Rupture Disc Assemblies Designed to Protect Tanks Against Implosion or Overpressure Conditions

CAL-VAC POS-A-SET
CAL-VAC and POS-A-SET
Continental Disc Corporation's CAL-VAC® and POS-A-SET® Rupture Disc Assemblies are highly accurate, double acting pressure relief devices designed to protect processing and storage tanks against implosion or overpressure conditions that can occur in:
  • Positive Pressure - overfill, external fire, steam regulator failure 
  • Vacuum Relief  - liquid pump out, insufficient flow through sanitary vent filer, flash vacuum due to CIP cool rinse, primary vent malfunctions, blanket gas or air regulator failure
Both designs relieve pressure settings starting as low as 1 InWC (inches water column) differential. The difference in the CAL-VAC Rupture Disc and POS-A-SET Rupture Disc is the orientation of the components to meet the relieving requirements. The CAL-VAC Rupture Disc relieves ultra low pressure in the vacuum (negative) pressure direction, while the POS-A-SET Rupture Disc relieves ultra low pressure in the positive pressure direction.