Rotary pump compatibility
Hi! I found this project to be really exciting! Curious about the suitability of using the latest smart coffee gear on an espresso machine with a Rotary pump - any thoughts, experiences or recommendations? Contrary to a vibration pump, Rotary pumps require quite some energy to get started, and therefore might not be suitable for any pressure profiling, unless doing it steplessly, regulating rpms, or...? (It's a 10+ years Rocket Cellini Evoluzione R)
134 Views
I can think of three approaches to controlling flow with a rotary pump machine. The first is to control the flow of electricity to the motor which drives the pump. I don’t know if this is possible or not. I read the data sheet from Fluid-o-tech and it is not clear to me. We could ask them.
The second is to use a needle valve or other means of flow restriction. This is what the mechanical flow control devices do. I can think of two ways. In the first approach, we use a 3-way solenoid to create two paths of brew water. The first path is at full pressure, and the second path meets with flow restriction. So now we can have preinfusion, restricted flow, and full flow. The restricted flow path could flow through a manually adjustable needle valve, so you can tweak the restriction. Now the electronics can pull shots with preinfusion, then full pressure, then lower pressure. Or whatever.
Then the other approach is to implement an electronically controllable flow restrictor, but I’m not sure what device can be used.
Of these approaches, I like the 3-way solenoid approach the best. It requires some reworking of the machine, but it shouldn’t be too extensive.