The Rancilio Silvia has a vibratory pump. The principal advantage for a home machine is that the vibratory pump develops pressure quickly and is relatively compact. The principal disadvantage - significant vibration and noise. The engine of the vibratory pump is an electromagnetic coil attached to a fluid piston. The coil moves back and forth when energized with alternating current - in just the same manner as a loudspeaker coil. This drives the piston back and forth - pushing water through a one way check valve to pressurize the boiler with water.
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| Rancilio Silvia - Vibratory Pump Installation |
You can see in the photo that the pump is supported by two rubber mounts designed to allow the pump to move laterally and offset the vibration of the piston motion. These mounts are 12 years old, and have partially collapsed under the weight of the stainless braided discharge hose.
I did a fair bit of research online before coming up with my noise reduction strategy:
- Improve the pump installation and correct the collapsed rubber mounts;
- Add vibration damping material (Dynamat or Noico) to as much accessible sheet metal as possible;
- Add cushioning to the drip tray and drip grille to reduce rattling.
Pump Installation Upgrade
Let's start with the pump installation. I was into the repair project before I realized that I should replace the pump rubber mounts, so I wasn't able to get replacement parts in time. So - I reversed the mounts to try to correct the sagging, and I added some closed cell foam underneath the pump to help support it from sagging under the mounts.
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| Vibratory Pump Installation Upgrades - Reversed collapsed rubber mounts, added closed cell foam under pump |
I made sure to install the discharge hose in such a way to ensure it wasn't touching any of the metal panels of the machine, to help avoid transmission of vibration to the sheet metal. I also
corrected the leak in the stainless steel 90 degree fitting at the pump outlet.
Vibration Damping
The next tactic was to install vibration damping sheet to as much of the accessible sheet metal on the machine, with the aim of reducing vibration transmission. A common brand name for vibration damping material is Dynamat. I ended up using Noico sheets - just because I found a format and quantity online which was well suited to the size of the Rancilio project. One thing I checked was the operating temperature of the Noico sheet - it's rated to 210F (about 98C).
I was careful to avoid placing this material too close to the boiler or group head components, and I insulated the boiler to help reduce the temperature within the front case.
I was also
installing a PID controller, so I had to disassemble the machine anyway. I did the PID installation at the same time as the vibration damping sheet installation, saving time.
I installed damping sheet on the following components:
- Main frame - side columns and base
- Rear cover
- Front cover
- Pump cover
- Top cover
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| Sound damping sheet installation underneath base |
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| Sound damping sheet installation front cover |
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| Sound damping sheet installation main frame around pump |
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| Sound damping sheet installation pump cover |
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| Sound damping sheet installation pump cover |
I used a 2" rubber ink roller to roll out the damping sheet, and make sure there were no gaps in the adhesive or air bubbles under the sheet.
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| Sound damping sheet installation rear cover |
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| Sound damping sheet installation top cover. Note installation of strips only to allow heat to warm top cover to keep cup heating function. |
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| Sound damping sheet installation - with front and rear covers and pump cover installed. |
Conclusion
So - what's the net result of the noise control work? A fairly noticeable improvement in noise control. One problem however - the drip tray grate still rattles during a shot - so I added some cushioning to reduce the impact of the rattle since it wasn't practical to add sound damping material to the grate.
The machine runs quite quietly now and I can make coffee in the kitchen directly below the master bedroom, without waking up my significant other. Worth the effort? Definitely!
Sources and Links
I hope you found this post useful. Feel free to ask questions in the comments section below. I answer all questions. If you're interested, you can help support this site by using the following links to Amazon.com in the United States. My go-to place for genuine Rancilio Silvia parts in Canada is Espressotec.com.
