The Problem with Competitor Filter Presses
I’ve always wondered why everything in our industry, particularly in the processing, was required to be food grade Stainless Steel; yet none of the filter presses were being built to those standards. A long time ago a representative of one of the major equipment manufacturers told me, “It’s too expensive to build filter presses out of stainless steel”… That’s always bothered me.
Over the past year and a half Smoky Lake Maple Products has been exerting great effort into the development of the best filter press in the maple industry. We’ve succeeded. We’ll be offering it for a cost comparable to the aluminum and plastic units currently on the market. We’re very proud of it.
The press is 100% Stainless Steel. The frame is stainless steel. The plates are stainless steel. The air diaphragm pump is stainless steel. All fittings and hardware are stainless steel. All 304 Stainless Steel. We’ve created the only indisputably food grade filter press in the industry. And it looks as professional and beautiful as the rest of the equipment Smoky Lake has become known for. It’s easy to compare this press against any of the cast aluminum models and see how stunning it’s beauty is.
Every unit is built to be expandable. A hobby producer can start with either the small platform or the large platform and chose the optional Hand Operated Plastic pump and load as little as 6 filters at a time. As this hobby producer grows they can expand the unit in increments of 4 filters to a total of 10 on the Small Platform or 20 on the Large Platform. That producer can chose to upgrade to the Stainless Steel Air Diaphragm pump at any time, all mounts and connections are in place and ready for such an eventuality. This system is meant to last a lifetime of syrup production, growing with the producer as they expand their crop.
Each window plate will hold 3 – 1/4 cup of DE.
Finally it’s literally impossible to put any of the plates in backwards, thanks to the foresight taken to offset the hangers on every piece. Most experienced producers know how frustrating it is when they accidentally put only one plate in backwards, not going to happen with the new filter press from Smoky Lake Maple Products.
Advantages of an Air Diaphragm Pump
Soft Start (low psi and low flow for start-up)
With soft start, the flow AND pressure are very easily controlled. You can pump a few tablespoons at a slow, low pressure until you see that everything is correct. Then crank up flow by giving it more air.
In contrast, with a gear pump/electric motor, the pressure and flow start immediately/violently because a gear pump is a positive displacement pump. That means that for every revolution of the pump, a defined amount of liquid MUST come out of the pump—every revolution! And the outlet pressure is relatively MUCH higher. Because of this, there is no forgiveness if something is not hooked up correctly or some valve is not set right.
Easily Controlled Pressure (in filter chambers)
As the filter press fills with DE and reduces or stops flowing, it’s very simple to twist the regulator knob up a bit to resume pumping. This can be done at any time, at any flow rate, from stopped to almost wide open. Of course, this is dependent on having an air pressure regulator in-line between the air compressor and the diaphragm pump.
Variable Flow (less air pressure for less flow, increase air pressure for more flow)
If you are pumping filtered syrup into your canner while you are filling small bottles, you can turn the pressure down low and slow. On the other hand, if you are filling barrels or 5 gallon containers, turn up the air and let it rip!
Harmless Stall (if/as filter plugs)
A HUGE advantage of air pump versus electric motor pump is that the air pump can remain “stalled” for hours (days!) without harm to your equipment. Try that with an electric motor driven pump!
How to Choose a Size
The below chart estimates how much syrup can be filtered in a single session based on the number of filters in your press. In other words, this is how much syrup could be filtered before the press needs to be cleaned. More Filters = Higher Capacity. The actual number of gallons filtered will depend on how much sediment is in your syrup to begin with. Dirtier syrup will clog/fill the press faster.
|Number of Filters||Gallons of Syrup Filtered per Session|
|6 filters||15 to 24 gallons|
|10 filters||25 to 40 gallons|
|12 filters||30 to 48 gallons|
|16 filters||40 to 64 gallons|
|20 filters||50 to 80 gallons|
Main Principals to Understand
- The filter papers do NOT do the filtering. Rather, a natural, powdery, food grade material called diatomaceous earth (DE) does the filtering. The papers only provide a backstop to catch and hold a layer of DE. The DE builds a permeable layer on the papers, and keeps growing or building out as more DE, dirt and syrup are introduced to the press.
- The DE will hold a certain amount of “dirt” while still allowing flow. If too much dirt is deposited on the surface of the DE, the flow will slow or stop, and pressure will rise. If there is excess DE for the dirt load, syrup will simply flow faster and with less pressure.
- Many variables will determine how much syrup you can filter before needing to clean out the filters: The amount of dirt or nitre in the syrup, the temperature, the amount of DE being used, etc.The hardest variable to determine is how much dirt is in your syrup. Syrup that has settled for several days doesn’t contain nearly as much dirt as syrup from the bottom of a barrel. Syrup directly off the evaporator contains a dirt load somewhere in between these two extremes. Your press might only be able to filter 1 gallon of “sludge” from the bottom of a barrel, or it could do 20 times that amount if it is fed well-settled syrup. It all depends on the TOTAL amount of dirt in the batch, not on the number of gallons of syrup.
How much DE do I need?
Each 7” window plate can hold up to 3¼ cup of DE. The press will be “full” when enough DE has entered the press to fill each window plate.
When purchasing DE, you must make sure that it is food grade (also sometimes called “human grade”). You will find that it comes in many different particle sizes. Note that a larger particle size can hold more dirt. A 2017 article in Maple Digest suggested that having too fine of a particle size could actually filter out some of the good maple particles and affect flavor. In conclusion, we suggest using the coarsest grade available (For example, 5000 or 4200 Dicalite).
One 7” Window Plate = 3 ¼ cups DE
Two 7” Window Plates = 6 ½ cups of DE
Three 7” Window Plates = 9 ¾ cups of DE
This rough estimate equates to about ¼ cup – ½ cup of DE for every 1 gallon of syrup you are filtering. The exact amount depends on the amount of dirt and nitre in your syrup. (See the Main Principals section for more discussion on this topic.)
It is better to go heavy on the DE on the first two to five quarts of syrup that you run through the press so that you can build a nice layer inside the press.
How Much Syrup can I Filter Each Time?
We recommend filtering at least 3 gallons of syrup at a time. You will find that filtering larger batches will be more efficient. If your pressure exceeds 65 – 80 psi, we recommend stopping to change the filters and clean the press. (See the “Shortening the Bank” section for suggestions on filtering small amounts of syrup.)
- Never touch the press with bare hands when it is hot.
- Wear heavy rubber gloves and safety glasses while operating the press.
- Inspect all hoses before starting to make sure they are secured and in good condition.
- Inhalation of DE can be harmful to the lungs. It is recommended to wear a mask over nose and mouth when handling DE.
- Handling DE may dry out the skin. It is recommended to wear rubber gloves when handling DE.
- High pressure within the press could potentially cause syrup to unexpectedly squirt out from between the plates. If you are filtering at over 50 psi, throw a towel over the filter press as a precaution.