November 13, 2009
What is a tub grinder?
As you know from reading this blog, I am a very serious gardener and am very serious about my compost yard. About once a year, we hire a tub grinder to help us out. In the course of the year, my ground's crew amasses quite a large pile of organic debris from the farm including stumps, logs, and brush. All of this material will eventually decay, however, to speed the process up by many years, a tub grinder is necessary. Basically, material is fed into this large piece of equipment, where it is hammered into much finer wood chips, accelerating the decomposition of this organic matter.
Dan Repola, of Material Processors, located in Spring Valley, New York, has been at the farm working hard on this project. Once all the wood has gone through the tub grinder, Dan passes it through a second time to make it even finer. He also screens the older piles of decaying matter, turning them into the dark and rich compost that I like to call 'black gold.' I hope you enjoy these photos of this amazing process.
1 This is approaching the tub grinder in the compost yard with piles in various stages of decay.
2 As you can see, this is major heavy equipment.
3 An excavator is used to grab big mouthfuls of logs and brush.
4 It is then transferred into the revolving tub of the grinder, which, by the way, measures 10-feet 6-inches across.
5 As the tub revolves, a hammer mill below, shatters the wood into fragments.
6 Those fragments travel on a long conveyor belt, forming a large mound.
7 You can see how finely the wood is ground up.
8 What is Laura taking a picture of?
9 Oh! It's Eliad in the Hi-Lo taking a picture of Laura!
10 Eliad got a better view from above.
11 That's Dan in the excavator feeding the tub grinder.
12 As the tub spins, friction actually causes some of the wood to smoke.
13 A better look
14 In one year, this wood pile had gotten quite large.
15 Another view of the ground up wood. By the way, it's very fragrant.
16 When the pile gets too tall, Dan uses the claw to push it down a bit.
17 This machine can lift even a mighty tree trunk.
18 It's hard to imagine that this could fit into the tub grinder, but it did!
19 Dan retrieves the nicer looking wood from the pile that he thinks will make good firewood.
20 That wood is sawed into manageable pieces and is neatly stacked for splitting into firewood.