Slurries are some of the most challenging fluids to pump. They’re thick, filled with solids, and oftentimes highly abrasive. Plugging is also common with slurry applications. Valves designs that provide areas for slurry to settle out and solidify are of course not recommended. The abrasive solids in slurry also grind on equipment in the system, wearing out internals and preventing valves from keeping their tight seals.
Downtime and maintenance cost can be minimized, however, by simply knowing which features to look for in a slurry valve. Here are the 6 things our valve team recommends you look for when selecting a slurry valve.
1. Durable and Replaceable Valve Seats
Seats have two functions, to protect metal components within the valve, and keep a tight seal to prevent leaks. Consider natural rubber for seat material, as this tends to hold up best against abrasive slurries.
Also look for valves with replaceable seats. In abrasive applications like slurry, being able to quickly change out a seat is critical for minimizing downtime and maintenance costs.
2. Full pipeline opening
Minimize the valve’s exposure to the slurry with a full pipeline opening, or full-port.
3. Positive Shut-Off
Slurries such as fertilizers and chemicals are harmful to the environment and workers. Therefore, it’s critical that the slurry valve selected has positive shut-off qualities.
Positive shut off means that the valve has a stem that drives the disc against the seat. Unlike a diaphragm valve which can leak if there is a loss in air pressure, or melt if in a fire, a positive shut off valve requires the physical turning of the stem to open and close.
4. Proper Materials
Because slurries are usually highly corrosive and abrasive, it’s essential that the right materials of construction are selected.
We usually recommend the components are coated with a hardfacing material, like Stellite. Stellite is made of cobalt-chromium alloys. This material has high wear resistance properties.
5. High Pressure and Temperature Ratings
Know the characteristics of the slurry before selecting the valve. Some slurries require heat and high pressures to transport it long distances. The pressure and temperature of the slurry will dictate which materials and elastomers should be used in your process.
Occasionally, slurries need to be flushed from the system. The self-draining feature helps to reduce maintenance downtime, and is most likely an operator’s favorite feature.
Slurry is a challenging medium for every piece of equipment in the process. You can minimize the effects of corrosion and abrasion with proper selection up front. To maximize your investment, speak with a valve engineer who is well versed in applications like yours.
Need help selecting the right slurry valve for your process? Ask us about it! We gladly provide technical assistance to businesses and municipalities in the United States.