Izory® – Zirconia ceramic seats were used in ¼-turn ball valves to improve the life of the valves from as little as 30 days to more than 9 months.
A few weeks ago, a California company contacted Refractron to discuss the possibility of making Izory® ceramic balls and seats for ¼-turn ball valves. They had several major oil producing outfits located in the state that were running into problems. They relied on 3-inch ¼-turn ball valves for controlling the flow of the crude oil from the wells to the pipelines. The current valve design used a stainless steel ball and soft polymer based seats. This design worked all right, but was subject to unexpected failures, which obviously can’t be tolerated in any application let alone at an oil production field.
We said we could definitely make the parts resist wear and corrosion and last longer. We have had an immense amount of experience with this type of application.
Right away, we dispatched a representative to the company’s plant in Bakersfield, CA to review the application and components in more detail. What they found was that the stainless balls in the valves were heavily worn; the seats were no longer sealing the crude oil flow against the ball, which was causing the failures. The valves themselves ranged in size from ½” to 8” in diameter. These valves faced temperatures of up to 150º F and pressures of up to 800 psi. Additionally, the crude oil that was being pumped through the valves was highly loaded with corrosives and abrasives because of naturally occurring SiO2, CO2, H2S, H2O, and sand. This combination of heat, pressure, and abrasion caused the stainless steel and polymer valves to leak at random, often after only 30 to 60 days of use.
After assessing the situation and conducting a brief consultation, the customer suggested that the stainless steel ball should be replaced with an Izory® zirconia ceramic ball. They also wanted to start with a 3” valve design because it is commonly used in a field where it can be easily monitored.
After reviewing all the information we suggested they first only replace the seats of the valve (and of course stay with the 3” design).
We made this decision based on analysis of the used parts. It looked like the polymer based soft seats were embedded with the sand particles. And so, as the valve opened and closed, the sand was scratching the stainless valve ball. The scratching ultimately acted like sand paper wearing the ball and causing the valve to leak. The abrasion caused the valves to leak after only 30 to 60 days. If only we could stop the seats from becoming embedded with sand, then the ball would last longer. The customer agreed that was a good suggestion and we would start with only replacing the seat. Replacing only the seat, instead of the ball, was also a less costly approach to this problem application. The manufacture of the ball with the holes for the stem and the through bore would be very costly to manufacture. The seats used a much more straight forward manufacturing process and used much less ceramic material. All of this made replacing the seats a less expensive proposition.
In order to replace the soft polymer based seats, the valve needed a slight design change. The Izory® zirconia ceramic seats were much harder than the polymer, and thus adjustments had to be made to ensure the valves stayed leak tight. This was accomplished with some slight dimensional and tolerance changes.
The initial set of valves using the Izory® zirconia ceramic seats worked very well. They were taken out of service after more than nine months, which was a 450% to 900% improvement!
There were many benefits to using Izory® zirconia ceramic seats. There was a reduced need to replace valves, so more oil was pumped without a service interruption. Less time was spent by field people for maintenance, resulting in less overall downtime. All of these benefits culminated in better, more cost effective operations. They directly influenced the company’s bottom line, saving them money and giving them value.
Izory® zirconia is an advanced ceramic that is extremely tough, wear resistant, corrosion resistant, and has a low coefficient of friction. It can be used in high temperature applications. Izory® zirconia is extremely well suited for designing components for valves, chokes, pumps, and any other flow control devices. Izory® zirconia is a replacement for tungsten carbides, stainless steels, polymers and exotic metals when the applications are the most rigorous. It can be easily formed into any shape, from a simple ball to a very complex check valve cage. Anything design that can be made in metal or a polymer can be made in Izory® zirconia.