Releaser hard on pump

[Bricklayer]

I have a Lapierre vertical mechanical releaser 12” x18” It works flawless every year except for 1 thing.
When it dumps it causes the vac pump to go down to 0 and freewheel then when the dump is done and flapper sucks back in it goes from pulling no vac to basically deadheading the pump. I spun 2 shafts on the vac pump the last couple years. Was able to fix them and strengthen them up so they don’t spin again. But it’s still pretty hard on the pump and motor.
I was thinking of installing a vac line with a check valve to where the main lines come in to provide continuous vac. But when sap is running hard or when the vac is turned off this part of the releaser fills with sap sometimes full to the top untill vac in releaser matches the vac on the lines. Then it goes into the releaser.
Gotta be an easy way to solve this.

[DrTimPerkins]

Put a check-valve between the pump and releaser to prevent this.

[Bricklayer]

I have a brass swing check valve on the pump. Without it the pump will spin backwards when it shuts off.

[wiam]

The way you describe it I don’t think your releaser is working properly.

[maple flats]

I agree with wiam. I never used a single mechanical releaser, both of mine have been doubles, but I doubt the design would be for what you describe. I advise you contact Lapierre, they should be able to trouble shoot on the phone.

[GeneralStark]

A also agree with Wiam. I had a single vertical for several years and it had two flaps. One on the bottom of the main chamber and one on the outlet of the mainline manifold. When the main chamber dumped the flapper on the outlet of the manifold would shut to hold vac on the mainlines. It seems like this is not happening in your case...

[wiam]

Is the vacuum in your top chamber going to 0? Sounds like you’re saying the vacuum on pump side of releaser is going to 0? If top chamber is holding vacuum then flappers are ok and the plunger either is not going full stroke or one of the o-rings could be bad.

[Bricklayer]

Top chamber holds vac 100%. Needle dosnt even move when it dumps. I took the plunger apart today and orings look perfect. Put a little food grade grease on them yo lube them up. Same thing. But releaser dumps perfectly.
We have 1 more day to the season and I’ll be bringing it home and cleaning it. So I’ll fiddle with it then. I switched over to electric motors on the pumps this past couple weeks. So might look at getting an electric releaser for next year. See how it goes.

[ennismaple]

Bricklayer - we have 2 of these releasers that used to run off SP22 pumps (now on an Airtech on high vac) and we never had the problem you described. The pump would spin backwards if you turned off the pump without releasing the vacuum first. If it's filling up to the top and basically backing up into the header where the mainlines come in maybe you need to adjust the ring with set screws that limits the travel of the float on the float rod? If it's set too high it will let the chamber fill up too much.

[Bricklayer]

Watched another exact same releaser yesterday do the exact same thing mine is doing
I don’t think I explained the issue very well. So I’ll explain again.
I have a delaval 73 running at 22” hg vac gauge then Check valve at the vac pump
Vac line runs to releaser.
2 x1” mainlines comming into upper releaser chamber.
Vac level in upper chamber matches vac level on vac pump. And upper chamber needle does not move at all while releaser dumps. So flappers are working.
When float trips the switch and releaser dumps the vac gauge on pump dosnt move.
It’s when it’s finished dumping and the flapper closes and it switches back to applying vac to the main chamber is when the needle on the pump drops to 0 for a split second then hits back to 15hg then up to 22hg.
I think this is what’s causing my pumps to break shafts. This hard hit multiplied over thousands of times through the season. The shafts never break at the start of season. Only usually towards end of season.