Im thinking of adding an electric valve between my OPV and boiler on my Saeco Via Venezia. You can see where on the top left of this picture. After the valve connected to the pump. http://guide-images.ifixit.net/igi/cjBftKfKQEJ1gFTL.medium
I want this valve to be able to open fully to let the full 9psi through and close partially to only allow 5bar for preinfusion.
I saw a mod of someone doing this after the boiler by using a 2 way solenoid valve and a check valve at the end that drains to the tank. I want to attempt to get the same type of results but still have the steam wand functionality(as he connected the solenoid and valve where the steam wand was). You can see what he did here: Click Here (www.youtube.com)
calblacksmith Moderator Joined: 25 Nov 2007 Posts: 5,761 Location: Riverside, Ca, U.S.A. Expertise: I live coffee
Espresso: ECM Veneziano A1 Grinder: Many different commercial Vac Pot: 40s era Silex Drip: Milita, Bunn&Curtis... Roaster: Cast iron pan, gas burner
Posted Thu May 17, 2012, 6:07am Subject: Re: What kind of valve do i need?
I do not know of any valve that has built in restriction. If you want two pressures, you might think of using a valve that directs water one way when off and a second way when activated.
In the off position, have it go the normal way for the water to flow in the stock machine. When activated, send the water through a second OPV to adjust the pressure to your desired pre infusion. I would add a check valve in both lines so that the water can not reverse flow anyplace but it may not anyway due to the way the OPV works.
It is a fair amount of work for a moderate priced machine but do it if you want. Most people, I think, would just turn the pump on for a second, turn the pump off then start again after letting the coffee get wet.
YMMV!
In real life, my name is Wayne P.
Feed the newbs, starve the trolls and above all enjoy what you drink!
Posted Thu May 17, 2012, 11:05am Subject: Re: What kind of valve do i need?
thanks wayne for the idea. i was getting thoughts of pressure profiling (starting off with 5bar during preinfusion, full pressure for a bit and then finishing off with some slow 5bar...or whatever profile i felt like using with a manual switch) and not just pre-infusion.
so in my head, with your idea, the valve will have the inlet hose from the 9bar factory opv, then a switch that will allow it to open up directly into an unrestriced line and another into a second opv adjusted to 5bar then both hoses possibly connected to a T with a check valve on each side.
so the next question, what would this solenoid valve be called? i guess i'll be heading off to google haha
im hoping it'll be worth the trouble.
*dreams of an 80 dollar pressure profiling strada/slayer* hahah :P
Posted Thu May 17, 2012, 11:13am Subject: Re: What kind of valve do i need?
frank828 Said:
so in my head, with your idea, the valve will have the inlet hose from the 9bar factory opv, then a switch that will allow it to open up directly into an unrestriced line and another into a second opv adjusted to 5bar then both hoses possibly connected to a T with a check valve on each side.
yeah im seeing some mini low wattage 3 way directional control solenoid valves. i'll control the solenoid with a rocker switch or something attached to the body.
also i realize i need a shuttle valve instead of the T connector and check valves. The shuttle valve is a T with a ball inside that will block the flow depending on which side the water is flowing from.
Now i need to figure out the hose size and fitting sizes.
Posted Thu May 17, 2012, 12:13pm Subject: Pressure Profiling via 3-way directional solenoid valve
i'm thinking something like this can be integrated into pretty much any boiler espresso machine to do pressure profiling.
the following is just to get my thoughts down...
pump -> factory opv set to calibrated pressure to get 9bar during brew -> connected to a 3-way directional control solenoid valve(controlled by a simple rocker switch) -> two output hoses - #1 hose connected to one end of shuttle valve running full calibrated pressure. #2 hose connected to additional OPV set to allow 5bar during brew(drain hose to water tank) connected to other end of shuttle valve -> connect ouput of shuttle valve to boiler.
*additional thoughts, many standard saeco machines use 1/8" barbs and 5mm IDx 7mm OD silicon tubing (http://www.espressoparts.com/V_551) to connect to and from boiler. might want to use existing connecting hardware from existing tubing to boiler and attach to outlet of shuttle valve(or replacement here Click Here (espressocare.com) ). should be standard 5x7mm. look into getting 1/8" barbs on the shuttle valve and 3-way solenoid and using the same silcon tubing. Ensure proper max PSI for connections and shuttle valve. 9bar = 130.5psi, 15bar = 217.6psi. Probably safer to get items closer to 15bar. hmm, teflon may be a better option just to be safe regarding heat and pressure.
now i need to figure out a reliable way to measure pressure. im hoping the steam wand pressure gauge will do the trick. Otherwise maybe get a portafilter mounted pressure gauge.
calblacksmith Moderator Joined: 25 Nov 2007 Posts: 5,761 Location: Riverside, Ca, U.S.A. Expertise: I live coffee
Espresso: ECM Veneziano A1 Grinder: Many different commercial Vac Pot: 40s era Silex Drip: Milita, Bunn&Curtis... Roaster: Cast iron pan, gas burner
Posted Thu May 17, 2012, 2:05pm Subject: Re: Pressure Profiling via 3-way directional solenoid valve
As these machines have the pump and pressure regulation before the boiler, the boiler and by extension the hot water wand (steam might give you a false reading due to compression, just guessing here) will see the boiler pressure. This isn't quite the same as pressure on the puck but it will be close enough for most uses.
The specific parts, I didn't look at. Give it a try and see, it shouldn't cost much. Even a manual valve will work for switching, like is used to switch between fuel tanks, just a manually operated "y" valve. The handle could be out the side of the machine as well as some sort of adjustment knob for your second pressure regulator. A totally hand operated system, OR not LOL!
In real life, my name is Wayne P.
Feed the newbs, starve the trolls and above all enjoy what you drink!
Symbols: = New Posts since your last visit = No New Posts since last visit = Newest post
Forum Rules: No profanity, illegal acts or personal attacks will be tolerated in these discussion boards. No commercial posting of any nature will be tolerated; only private sales by private individuals, in the "Buy and Sell" forum. No cross posting allowed - do not post your topic to more than one forum, nor repost a topic to the same forum. Who Can Read The Forum? Anyone can read posts in these discussion boards. Who Can Post New Topics? Any registered CoffeeGeek member can post new topics. Who Can Post Replies? Any registered CoffeeGeek member can post replies. Can Photos be posted? Anyone can post photos in their new topics or replies. Who can change or delete posts? Any CoffeeGeek member can edit their own posts. Only moderators can delete posts. Probationary Period: If you are a new signup for CoffeeGeek, you cannot promote, endorse, criticise or otherwise post an unsolicited endorsement for any company, product or service in your first five postings.
= No New Posts since last visit 