Note 3 - Inventory

12 Months Ended

Dec. 31, 2017

Notes to Financial Statements

Inventory Disclosure [Text Block]

NOTE

3

- INVENTORY

Inventory consisted of the following at

December 31,

201

7

and

December 31, 2016:

	201 7			201 6
Furnace parts and supplies	$	400,589		$	336,799
Raw materials		1,260,209			1,216,098
Work in process		2,123,418			2,499,242
Finished goods and filtration systems		2,297,743			2,544,080
Reserve for obsolescence		(1,420,093	)		(1,421,345	)
Net Inventory	$	4,661,866		$	5,174,874

A

portion of the inventory is held as collateral on a lines and credit and guarantees with financial institutions. See Note

8.