The Skillman Cup Cage
The standard cage sold by all other manufacturers has always been a compromise of ball and seat life versus cage life. If a hard ball and seat was used, then the cage would fail faster. If a hard cage was used, then the ball and seat would fail faster.
One thing is certain, there will be failure.
By design, something has to fail in a standard cage. The fluid pushes the ball up as it enters the bottom of the cage, and then the fluid then flows around and over the ball, pushing it down as it tries to exit the top of the cage. This agitation of fluid spins the ball, beating it against the ball guides of the cage, causing both cage and ball & seat failure. Bad cage design creates bad fluid dynamics.
The Skillman Cup Cage was designed with three major solutions in mind.
1. Design a cage with smoother fluid flow dynamics and more fluid flow area through the cage.
2. Design a cage that will not wear or beat out, period.
3. design a cage that was ball and seat friendly under all pumping conditions.
When fluid enters the Skillman cage it pushes the ball up and into the top of the cup. Holes in the sides of the cup direct fluid into the cage body where it flows around the cup, not the ball. There is a hole in the top of the cup. As fluid flows over the hole in the top of the cup to exit the cage, a low pressure area is created above the cups top hole which holds the ball in place. There is no movement of the ball as fluid moves through the cage.
Some of the worst damage to a cage and ball & seat happens during fluid pound. This is when the pump barrel is just partially filled with fluid and the standing valve is closed. The plunger and traveling valve start the down stroke but because there is no fluid in the top of the barrel, the traveling valve stays closed. The traveling valve is holding the hydrostatic fluid load of the tubing which can be tremendous in a deep well.
When the closed traveling valve impacts the fluid at the bottom of the pump barrel, the ball rockets off the seat and hits the top of the cage. In a standard cage, one point of the ball hits one point of the cage, thus directing all that energy to one point causing the most damage. In the Skillman cage, the top of the cup is formed with the same radius of the ball, so when the ball hits the top of the cup, it hits it's own form which is round. This keeps the ball from being damaged and defuses the energy over a larger area. Unless pumping very slow, even with good pump fillage, the ball hits the top of the cage at the start of every up and down stroke.
Watch the video of the Skillman cage compared to the insert guided cage considered by most to be the best on the market. And see the chart showing the flow area of the different designs.
One thing is certain, there will be failure.
By design, something has to fail in a standard cage. The fluid pushes the ball up as it enters the bottom of the cage, and then the fluid then flows around and over the ball, pushing it down as it tries to exit the top of the cage. This agitation of fluid spins the ball, beating it against the ball guides of the cage, causing both cage and ball & seat failure. Bad cage design creates bad fluid dynamics.
The Skillman Cup Cage was designed with three major solutions in mind.
1. Design a cage with smoother fluid flow dynamics and more fluid flow area through the cage.
2. Design a cage that will not wear or beat out, period.
3. design a cage that was ball and seat friendly under all pumping conditions.
When fluid enters the Skillman cage it pushes the ball up and into the top of the cup. Holes in the sides of the cup direct fluid into the cage body where it flows around the cup, not the ball. There is a hole in the top of the cup. As fluid flows over the hole in the top of the cup to exit the cage, a low pressure area is created above the cups top hole which holds the ball in place. There is no movement of the ball as fluid moves through the cage.
Some of the worst damage to a cage and ball & seat happens during fluid pound. This is when the pump barrel is just partially filled with fluid and the standing valve is closed. The plunger and traveling valve start the down stroke but because there is no fluid in the top of the barrel, the traveling valve stays closed. The traveling valve is holding the hydrostatic fluid load of the tubing which can be tremendous in a deep well.
When the closed traveling valve impacts the fluid at the bottom of the pump barrel, the ball rockets off the seat and hits the top of the cage. In a standard cage, one point of the ball hits one point of the cage, thus directing all that energy to one point causing the most damage. In the Skillman cage, the top of the cup is formed with the same radius of the ball, so when the ball hits the top of the cup, it hits it's own form which is round. This keeps the ball from being damaged and defuses the energy over a larger area. Unless pumping very slow, even with good pump fillage, the ball hits the top of the cage at the start of every up and down stroke.
Watch the video of the Skillman cage compared to the insert guided cage considered by most to be the best on the market. And see the chart showing the flow area of the different designs.