1° The context
Application : underground high pressure paste backfill systems
Historically, end users would use high pressure ANSI 600# knife gate valves off a branch pipe with flanged connections for the purpose of dumping residual paste and flushing waste, but the smaller 4” and 6” branches would become blocked through paste slurry solidifying between the short space between the main pipe flow stream and gate on the upstream isolated side.
Dump valves are also generally installed in overhead pipework which is secured to the roof of the mine tunnels making installation a challenge and the ability to “rod” or remove blockages difficult and dangerous.
The frequency in which the pipe became blocked with the knife gate valves was sometimes weekly, resulting in recurring maintenance and downtime to dismount the valves and remove blockages on installations located as deep as 1000m below ground.
There was also the continued risk of the entire pipe work becoming blocked with solid paste which could cost over $100000 to unblock or replace.
2° The challenge
The challenge presented to our representative and Guichon was to provide operators with a valve that would minimize dead space between the main pipe flow line and the point of isolation as well as have the ability to dislodge any solidified paste and open a clear flow path for the residual paste and flushing waste to “dump” out.
3° The solution
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| 1. A rod sealed piston valve Type 605N – DN6″x6″ – 600 Lbs instead of a knife gate valve. 2. No dead space in order to avoid cement build-up (accumulation). 3. A piston valve with scraping rings which will clean the piston, preventing the deposit of cement paste in the valve. 4 . A robust valve thanks to Guichon’s construction |
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The Guichon valve is now and has been running for 9 months. The customer has not had one blockage, nor any other issues during this time.
| Benefits for the end user |
| 1. Reliable system, no plugging 2. Significant reduction in maintenance costs 3. Improved safety for personnel.
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