• Separates abrasive solids in production fluids before they enter a downhole pump.
  • Extends life of all types of downhole pumps. Simple to install and inexpensive.


Figure 1 - Illustrates the flow path of produced fluids through the desander sub. Fluid enters the tubing through the inlet slots. The fluid must flow down through a spiral to enter the orifice tube and flow upward to the pump. Centrifugal action, created by the fluids flowing through the spiral, pushes solids away from the vortex flow of the orifice tube. Solids settle into the mud anchor or rathole. The clean fluid flows upward through the orifice tube to the pump.

Figure 2 - Illustrates the position of the desander sub when used below a rod type pump.

Figure 3 - Illustrates the position of the desander sub and the use of a seal in the casing for ESP applications.


The Sandtrap Downhole Desander is run in the tubing below a downhole pump. Production fluids enter the Desander Sub through its inlet slots. Centrifugal action created within the Desander sub separates solids such as sand, scale, and iron sulfide from the fluids. The solid particles settle by gravity into the bull-plugged mud anchor joints or the rathole.

For most reciprocating rod pump applications, the Desander Sub is substituted for a perforated nipple commonly run below a seating nipple. Instead of running one joint of mud anchor, as many joints as possible should be run below the Desander Sub. The mud anchor joints must have a bull-plug or a Dump Valve device on the lower end. A Dump Valve allows the solids within the mud anchor to dump into the rathole on each downstroke of the pump. The Desander Sub may be elongated in order to perform as a “poor boy” gas anchor.

When using the Downhole Desander below an electrical submersible pump (ESP), an ESP Packer is required. This system diverts all production fluids into the Desander sub, back into the casing, past the motor for cooling, and into the pump intake. Solids are collected in extended lengths of bull-plugged mud anchor.

The Downhole Desander may also be used below progressive cavity type pumps. The Desander Sub is run on the lower end of the pump. As many joints of bull-plugged mud anchor as possible should be run below the Desander Sub to serve as a sand trap.

Because no two wells are the same, The Cavins Corporation produces several models of the Desander. Please consult the chart below and contact our sales team, by email at and/or phone to an office location nearest you, to find out which Desander is best suited for your well conditions.