22 MASS. EXPERIMENT STATION BULLETIN 336 



Net Head (Ft.) Gallons Per Minute* 



4 .65 



6 1.05 



8 1.43 



10 1.80 



12 2.50 



14 3.34 



♦These were for short runs of about five gallons and rate would be lower for longer runs 

 with thicker filter cakes. 



The necessary head may be obtained in different ways : 1. The supply 

 tank may be put on the floor of the upper story of a building and the 

 filter below; 2. a platform may be constructed to support the supply 

 tank at the desired height; 3. or the tank may be raised and lowered by 

 a block and tackle or chain fall. Where a large amount of filtering is to 

 be done, it may be more economical to use a pumpf in connection with 

 a storage tank. A pump may be directly connected to the filter, in which 

 case it should be provided with a pressure control. For farm purposes, 

 the cider can be carried or hand-pumped to the height of the supply tank. 



The supply and mixing tank should be of wood. A barrel, with the 

 head removed for filling and mixing, may be used where small quantities 

 of cider are handled. Delivery to the filter should be through a rubber 

 garden hose, preferably five-eights inches in diameter. The tank may be 

 bored and fitted with a brass spigot, or the cider may be siphoned from 

 the barrel. It is convenient to have a cut-off in the delivery hose. A 

 convenient arrangement is a J4-inch gate valve at the lower end, fitted 

 with two nipples. One %-inch nipple with bushing will fit into the 

 inside of the hose and the filter tube can be attached to the other. This 

 arrangement is convenient for shutting off the flow to clean the unit and 

 for starting the siphon. The muslin tube should be wrapped tightly 

 around the nipple and tied with a miller's knot. 



tWhere a pump is used, it should be of bronze and with a minimum of metal in contact 

 with the cider. 



The muslin tube filter uses a '"filter aid", which is absolutely essential to its 

 successful operation. The "filter aid" used by this laboratory is known as 

 Hyflo Supercel and is manufactured by Johns-Manville Company, the nearest 

 local office being in Boston, Massachusetts. This product is a diatomaceous 

 earth which has been heated to a high temperature, a process known as calcin- 

 ing, to remove traces of organic matter which might cause off-flavors in the 

 filtered product. It is good practice to test a filter aid to see that it does not 

 impart an earthy flavor to the cider. This can be done by stirring a table- 

 spoonful of the product in a glass of cider, waiting for it to settle, and tasting 

 the cider. 



As noted under the description of the muslin tube filter, the filter aid is 

 carried down from the supply tank with the cider and forms a cake on the inside 

 of the cloth tube where it acts as a filtering medium by collecting the sediment 

 from the clarified cider. In general one pound of Hyflo Supercel is sufficient for 

 30 gallons of cider, although as much as one pound for 20 gallons, or as little 

 as one pound for 40 gallons may be necessary, depending upon the condition 

 and extent of clarification of the cider. The filter aid must be mixed thoroughly 

 with the cider before the filter is started and must bestirred during the filtra- 

 tion as otherwise it will settle out. 



About two gallons of cider must be run through and returned to the supply 

 tank before any is collected for use, because it takes about that quantity of 

 cider to build up the filter cake. According to the inventors of the muslin tube 

 filter the tube must be cleaned after 20 to 40 gallons have run through where a 



