It's important to use the right language to describe our units. While technically our core products are ejectors and eductors, we will use the term "JET PUMP" to encompass "the entire style of pump(s) which use a motive fluid (air, steam or liquid) to create an internal vacuum and impart a motive force on an entrained fluid."
Below is the accepted standard terminology of the pump and piping industry for units in this class or style of general pumps. However in practice, we note a high degree of interchangeability of these terms by those who are not experts in the field.
AN-JET is known for its expertise in designing both types of jet pumps. We specialize in more difficult field applications of pumping entrained solids in a fluid - fluids containing minerals, solids, oil slurries and sand. For these types of non linear applications, using a Peripheral Jet Pump is optimum due to the inherent clear throat of the design - but an Annular Jet Pump will work equally well (sometimes better) when using nominal inlet screening or filtration. We have used both in the field and both work.
Case-In-Point. Our newest 2" Annular Jet Pump - Model# AJ-20FP-20FP-SS - shown below allows up to a 3/8" solid (such as gravel, sand, biomass, etc.) to flow straight through the pump. Adequate inlet filtration at 1/4" screen opening coupled with a maximum solids density of 20% in solution, allow for reliable certainty of flow with little to no clogging. Most often it is the operator who determines if clogging will occur as many factors come to play. However rare, let's talk about clogging more below to reduce its infrequent occurrence.
Do Jets Pumps Ever Get "Clogged?"
Yes, infrequently, but on occasion all types of jet pumps can get clogged.
Clogging occurs because of several factors including: loss or cycling of motive pressure, unexpected or reduced motive volume, excess slurry density, filtration oversize, operator failure and operator usage error. However, best jet pump selection, adequate sizing, proper motive pressure, good filtration, right operation all can eliminate most all problems - including clogging.
Most industrial applications are "install and forget" types of installations. They just run and run. In more difficult applications where changes in environment are routine, all performance considerations must be known and reviewed in advance. Once your application and field routines are known, it's rare to have any form of jet failure when operated within the confines of the designed jet pump envelope.
Consider this. In liquid -liquid jet pumps a semi-clean motive fluid flowing through the jet pump dilutes heavier slurries. If clean water is not available, sometimes the addition of water helps the heavy slurries move faster and with less clogging potential.
As long as you stay in the 20% range of suspended solids, the jet pump WILL pump.
Add-on Valves for Jet Pumps
We encourage the use of a "purging valve" on the output of the jet pump. This valve (typically a full flow ball valve) redirects the motive flow and pressure BACK towards the Suction Inlet. This internal reversal of flow normally clears the jet pump of most blockages or obstructions. This important valve is "a routine addition" to any slurry or sand pumping operation.
We also require for safety a quick acting "motive fluid shutoff valve" close to the unit so an operator can shut off all motive pressure rapidly in case of human or machinery danger, blown discharge hose or other field failure event.
"Safety is never an afterthought"
We hope this brief technical discussion has helped you understand more about the world of Jet Pumps, their use and helped you identify any remaining questions for your AN-JET Sales Representative.
They will work hard to give you complete confidence in application of our products to your selection and purchase details.
If we don't know the answer to a critical question, we'll find out the answer together.