Mechanical Devices in the Home

PART VII

House-Cleaning Equipment

CHAPTER XXVI

Vacuum Cleaners and Cleaning Tools

185. Principle Upon Which Vacuum Cleaner Works. The principle of a vacuum cleaner is that, thru suction, dust and dirt are drawn from the floor or other surfaces into some container. If the power of the cleaner is sufficient, it may pick up anything—but cleaners having a moderate amount of power are somewhat more discriminating. They do, however, remove the fine, greasy dirt that brooms, brushes and carpet sweepers fail to get. The coarser dirt and ravelings may be taken up by a carpet sweeper, with a brush, or picked up by hand. The brush is combined with the cleaner in many machines (Fig. 98).

186. Different Kinds of Vacuum Cleaners. There are cleaners with bellows, pumps or fans to draw in air and dirt. The ones with bellows in them work on the principle of a bellows which is reversed so that when the air is drawn in, it brings the dirt with it. The other kind works with a fan which draws or sucks air from the floor thru a nozzle into the machine. In the machine, the dust is filtered out of the air and collected in a pan.

The machines with fans in them are mostly power machines, as the fan must revolve very rapidly. The hand machines are mostly of the pump and bellows types. Some are combined with the carpet sweeper, making two machines in one. With this device once going over the floor is sufficient for removing both coarse and fine dirt. The hand machines do not have as much power of suction as the power machines, but they do very satisfactory work. They are more effective than a carpet sweeper in removing dirt, but they do not get as much of it as the stationary cleaner. Removing the sharp grit from rugs and carpets lengthens the life of them so that the more grit a cleaner can remove without tearing the carpet, the more valuable it is.

When the pump type is being used, the piston is drawn up, drawing with it air and the dirt which is present at the point from which the air comes. A cloth filters out the dust. The air escapes from the machine before the piston is lowered to draw in more air and dirt. If this were not true, the dust would be forced back as the piston was lowered.

187. Nozzle of Vacuum Cleaner. The nozzle, or point of entry of air into the machine, is an important part of a vacuum cleaner. This is constructed so that it fits the surface from which the dirt is to be drawn, insuring the drawing up of dust as well as air.

The dirt is drawn from only a few square inches of surface at one time. The thoroness and rapidity with which the dirt is removed depends upon the strength of the suction or the power of the machine. Thus, hand machines may have to be moved over a surface several times if it is very dirty in order to get all the dirt.

Plain solid nozzles work best on carpets and other surfaces of similar kind. They are not effective on hard floors, but this is not essential, as dirt can easily be removed from smooth surfaces with a brush.

188. Cautions in Using Vacuum Cleaners. The difficulties to be met with in vacuum cleaners are leaks. First of all, the machine must be fitted together perfectly; if not, the dust drawn into the machine escapes into the air of the room instead of into the collection pan or chamber.

Machines are made air-tight, but to be cleaned, they must be taken apart. In putting them together, the housekeeper must take pains to fit them together perfectly.

Never neglect to empty the dust chamber. Keep the machine properly oiled. A punctured bellows or a leaky dust strainer will cause dust to escape after being drawn into the machine. These have to be remedied with new parts. Some machines leak because of improper manipulation, such as a too-fast or too-jerky motion in operating them. The directions for each machine tell how to use it—such directions cannot be given here because they differ so much.

When the pan has become over-full of dirt, the machine will necessarily throw out dust as well as air. Letting the machine get over-full of dust may ruin the machine by making some part leak continuously.

189. Difference Between Hand and Power Cleaners. Power machines differ from hand ones in that they are run by motor power (Figs. 99 and 99-a). They may have larger collecting chambers and may be stationary in the cellar and connected to the rooms by long pipes (Fig. 100). They must likewise not be over-full of dust. They must be kept properly adjusted. As the operation of the mechanism shakes the machine, it may loosen screws and nuts, so they must be kept tightened. The motor must also be kept in order. The motors used for vacuum cleaners are the same as those used on other power devices. They may be small electric motors, forming a part of the machine, or large motors which operate several machines.

In any case, they must be given the same care as any other motor of the same type. (See Chapter XXXVIII.) If they become overheated, they will not work well. They must be kept lubricated to avoid friction, and they must be kept properly adjusted. Fig. 100-a shows a number of different attachments for vacuum cleaners.

190. Carpet Sweeper. A carpet sweeper is a combination of brush and dust pan. The advantage of this device is that the dust is gathered into the machine as the brush rotates, due to the action of the wheels on which the machine moves. The dust is collected into pans at each side of the brush; these are covered so that the dust does not fly into the air as much as otherwise would be the case (Fig. 101).

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Oil the sweeper regularly about once a month by putting one drop of oil on the ball bearing on the hub of each wheel. Failure to oil carpet sweepers causes them to wear out quickly, to squeak, and to run hard. More oil than is needed only gathers dust and gums the sweeper.

Empty the sweeper (Fig. 102) each time it is used, even during the sweeping if necessary. Don't fill it to overflowing. Always open the pans by pressing on the dump levers, not by taking hold of the pans. Don't let the brush get tangled with hair, ravelings, etc. Take it out occasionally and clean it (Figs. 103 and 103-a). Cut along between the spiral rows of bristles with a sharp knife or shears, and the ravelings and hairs can be picked or combed out easily without injuring the brush (Fig. 104). Never try to pull them off whole. Also remove any accumulation of dirt or ravelings which catch in the wheels or bearings. Don't let dirt collect in any part of the machine. Keep it clean. Good sweepers work best without extreme pressure on the handle. Never put oil, water or any liquid on the bristles. Don't keep a sweeper on a warm-air register—it takes the life out of the bristles.

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191. Mop Wringers. There are two kinds of mop wringers to attach to pails. One is made of two flat surfaces which, when pressed together with the mop between (Fig. 105), squeeze the water out of it, and the other is made of two wringer rollers which, when brought together by a lever after the mop is put between them, rotate as the mop is pulled upward and wring out the water (Fig. 106).

Questions for Part VII

PART VIII

Devices for Preparation and Conservation of Food

CHAPTER XXVII

Pots, Pans, and Other Devices

192. Materials from Which Utensils Are Made. Since there is considerable choice in utensils made from different materials, the housekeeper may like to know something about these materials and about their care, and the effect of acids and alkalis upon them.

Russia iron is one of the older materials for pots and pans, and it still holds a place in cookery, for it makes bread, loaf cake and cooky pans, which give to the food a thin, brown crust, due, undoubtedly, to the way in which it conducts heat. (See tables on page 158.)

Tinned metal, which is well tempered, also, gives a thin, brown crust to layer cakes and pies. It makes good bread, loaf cake and cooky pans. Most of the cheap tin of today is iron-coated with very little tin. It does good work, but utensils made of it cannot be kept as well polished and as attractive in appearance as more heavily-tinned ones.

Sheet iron, heavy steel and cast iron make the most popular frying pans. The heavy iron, holding heat as it does, makes a desirable brown coating on most foods without the danger of burning experienced with frying pans of other materials. This is due to specific heat and conductivity of the metal. Sheet-iron frying pans are useful in cooking foods which are wanted on short notice. The small-sized ones are most in use.

193. Aluminum Alloy. Satisfactory frying pans are made from aluminum alloyed with other metal and cast. Real aluminum frying pans warp. They do not brown the food as well as materials that conduct heat less rapidly.

194. Cast-Iron Utensils. Heavy cast iron finds special favor in the making of pot roasts, bread sticks and popovers. It browns the roast and makes a thick crust on bread sticks and popovers.

All iron or tin utensils give better service as they become tempered with use. They must be kept dry in order to prevent rust. Do not use them for cooking acid foods.

Granite, cast aluminum and Russia iron are the popular and satisfactory materials for roasting pans.

195. Earthenware. For casseroles and bean pots, earthenware is a favorite material, the heavy glass gives equally good results. These materials are fitted for long, slow baking of food. They hold heat and conduct it to the food in such a way as to produce results which are difficult to duplicate with utensils of other materials.

196. Aluminum and Graniteware. Stew pans are proving satisfactory when made of aluminum and of high-grade graniteware. An assortment of pans and double boilers containing utensils of each material gives the best results, as the granite is most desirable for cooking some acid and very salty food, while aluminum is light and satisfactory for preparing other dishes. Never let food stand in aluminum or granite dishes after being cooked. High-grade graniteware is not as readily affected by acids as the low, cheap grade. Enameled ware, which is roughened by a dilute solution of vinegar, is likely to contain substances injurious to health. Ink will not stain good enameled ware. Graniteware, like glass and earthenware, makes a heavy crust on the dishes being baked in them. Graniteware is metal, coated with a sort of glass. It must be treated like glass. It cracks when dropped. Never set it on a hot stove when empty or cold, as the heat of the stove will crack it as it will glass. When hot, do not set it on a cold marble or a metal table top, as sudden changes in temperature will crack it. With proper care, granite and enameled ware give good service.

Graniteware is proving desirable for making utensils for use on electric stoves, the conductivity of the glass coating being so low, that it conducts the heat to the top of the pan slowly so the food in it gets to cooking quicker than in utensils made of most of the other materials.

Aluminum is easily dented and warped by extreme heat. It is attacked by some strong acids and strong solutions of salt, soda and fruit juices. Aluminum may be hardened by the addition of six to seven per cent of copper so that it can be cast into utensils. Great care must be used not to use cleaning powders which contain strong alkalis for cleaning aluminum ware. It has light weight, and, when polished, is very attractive. With proper handling, it gives good service.

197. Mixing Spoons. The wooden mixing spoon gives best results, as it does not mar the utensils, and the handle does not become as hot as metal. Hard maple or orange wood cut in a plain design makes the best spoon. Acids do not attack it. Plated silver or solid nickel spoons come next in usefulness. Softer metals wear off too fast to be satisfactory.

Nickel is a most desirable material for household utensils, but is very expensive. It is not in common use in this country.

TABLE SHOWING CONDUCTIVITY AND SPECIFIC HEAT OF METALS

CHAPTER XXVIII

Parers, Seeders, Grinders, Slicers, Etc.

198. Fruit and Vegetable Parers with Knives. Parers of the type with a knife have a fork-like device on which the fruit or vegetable is held while a knife blade, attached to a shaft governed by a spring, is pressed against the fruit or vegetable so that it cuts off a thin layer of the surface. Both the fruit and the knife are caused to rotate so that the whole surface of the sphere-like object will be covered by the blade of the knife during one or more revolutions of the wheel which operates them (Fig. 107). The knife is guarded so that it cuts only a thin layer from the outer surface of the fruit or vegetable. After the knife has made the complete journey over the surface, a device attached to the machine pushes the object from the fork so that a new one may be put in its place. Parers are quite complicated devices, but they have been perfected so that they are not clumsy, and some can core apples, stone peaches and slice the fruit.

Keep this type of machine dry so that it will not rust. Do not put it into water. Wipe off the blade of the knife and the fork when thru paring, so that the acid of the fruit will not discolor them and dull the knife. Keep the other parts dry and oiled. In time the spring governing the knife becomes weak and the machine will not do good work. This spring can be replaced on some machines. Parers are usually made of cheap material so that a new machine costs less than the repairs.

199. Parers Which Grate Off Skins. Another type of parer is a grater-like device. This is used in larger establishments than the ordinary home, but is useful where there is much canning of hard fruits or vegetables to be done at home. It consists of a container, the inside of which is rough like a grater. The vegetables or apples are put into the container with water enough to float and separate them, and the whole is agitated so that the vegetables coming against the sides have the outer surface removed or grated off. The water acts as the medium for moving the vegetables and for removing the bits of skin from the sides of the parer.

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Keep this parer clean by scrubbing the inside with a stiff brush and rinsing well with water after using. Keep in a dry place.

200. Seeders and Stoners. Seeders and stoners are constructed to punch out the seeds which are contained in cherries, grapes, raisins, etc.

201. Cherry Stoner. A simple cherry stoner (Fig. 108) consists of a small platform with a rod slightly smaller in diameter than a cherry stone. The cherry is put on an inclined plane so that it rolls over the hole. The cherry usually stays on the rod until this rod is lifted; then it passes between two guards which pushes the cherry off on another incline, where it rolls into a pan (Fig. 108).

There are several makes of stoners, but most of them work on this principle, whether the rod is lifted by hand or moved by a crank.

202. Grinders. Grinders are of two principal types—the roller and the burr. Coffee and other hand mills are of the burr type (Figs. 109 and 110). The food passing between these rough surfaces is ground to a fine powder as one is turned on the other.

203. Choppers or Meat Grinders. Choppers or meat grinders, as they are sometimes called, consist of a spiral channel, thru which the food is pushed along. Knives are placed in the sides of some machines to chop the food as it passes, while in others the knives are only at the outlet. Keep the fingers out of the hopper when the chopper is being operated. Keep the machine clean and dry when not in use (Fig. 111).

204. Choppers. Choppers have been made which really chop the food without crushing it, but these machines are so clumsy and noisy, that they have not come into common household use. They consist of chopping knives which are raised and lowered by levers and a crank.

205. Slicers. Slicers vary in design. The following illustrations (Figs. 112 and 113) show two different types. Care must be taken to guard the fingers when using slicers. Wash the knives and keep them dry when not in use. A soiled knife gets dull faster than a clean, dry one.

206. Lard and Fruit Presses; Sausage Stuffers. Presses and stuffers are of two types—the one which depends on the weight exerted on a long lever, and the other which depends on a screw to press the substances. The screw forces a flat board or surface down upon the food as it is turned. More pressure for the size of the device can be secured with the screw than is practical with a weight on the long arm of a lever (Fig. 114). The stuffer is like a press, except that the food is forced out one hole.

CHAPTER XXIX

Mixers, Beaters and Churns; Coffee Pots

207. Use of Mixers, Beaters and Churns. Mixers, beaters and churns are all devices for agitating or stirring food.

The simpler ones of these devices depend upon the motion of the hand (Fig. 115), while others have their velocity increased by means of cog wheels.

The turning of the large wheel turns the small wheel as many times as number of cogs on the small wheel is contained in the number on the large wheel (see Fig. 116). To get even more speed or to apply the power at a different angle, a series of wheels are sometimes used. A few mixers, like the bread mixer, are simply machines which take the hands out of the food, thus tending to a higher degree of sanitation, and a change in the motion which may not be so tiring as kneading. They do not increase the speed of mixing.

Bread made in a mixer has a somewhat different texture than bread kneaded by hand, but this does not change its nutritive value.

208. Care of These Devices. The principal care needed by these devices is that they be kept clean and the cog wheels dry. Very little oil should be used, as it would tend to get it into the food. Sometimes the rivet holding a wheel needs to be tightened, as, for example, when one becomes so loose that the wheel slips cogs. If it is too tight, the wheel may bind and work hard.

209. Freezers. The freezer is a mixer in a can which is in turn set in a freezing mixture of ice and salt.

Freezing can be done without stirring the cream. This makes a cream filled with crystals, while if stirred, it will be smooth and velvety because it freezes more evenly. The rapidity of freezing and the proportion of the ice and salt affect the fineness of the grain of the frozen dish.

A freezer is designed not only to stir the food, but to scrape it from the sides of the can. That which freezes first must be stirred into the middle of the can; otherwise, it would form a hard frozen layer of cream on the sides, leaving the middle unfrozen, and interfere with the turning of the paddle or beater.

In the bottom of the outside bucket, holding the ice and salt, is a socket into which the pivot on the bottom of the can fits. The can turns on this pivot in the direction opposite to which the paddle is turning. Some freezers are made so that the can stays stationary. The function of the pivot is then to hold the can in the center of the pail so that the paddle will be in the proper position to turn easily.

210. Care of Freezers. The pail of wood should not be stored in a very dry place when not in use. The can and paddle must be kept clean and dry so that they will not rust. The bearings and wheels which turn the paddle and can must be kept dry and oiled.

There is a hole in the upper part of the tub or pail in which the can sets, and this should be kept open as it is placed slightly below the level of the top of the can so as to drain off any water from the melting ice which otherwise might get into the can and make the food salty.

Some freezers have another hole at the bottom of the tub. This should be kept closed while food is being frozen. It is useful to drain off the water from the tub when the freezer is to be repacked or emptied. It should not be opened at any other time.

211. Churns. Churning can be done with almost any device which agitates the cream, but the churns which are simplest are most easily cleaned and least wasteful of butter. They are barrels or other containers which revolve or swing backward and forward.

Keep churns clean and well aired so they will not give up odors and flavors to the butter. After a churn has been used, rinse it with cold water and then wash it in hot water, to which washing soda has been added. Lastly, rinse with scalding water. Leave open to air when not in use, but protect from dust and dirt.

212. Drip Coffee Pots. Drip coffee is made in a funnel or a cup-shaped device which is suspended in a coffee pot (Fig. 117). This is made either of cloth or perforated metal. The coffee is pulverized and packed into the funnel. Cold water is poured on top of the coffee and slowly filters thru it, extracting flavoring substances. The water is heated after it has filtered thru the coffee.

213. Percolator Coffee Pots. A coffee percolator is a device put in a coffee pot to hold the ground coffee above the water and pump some of the water to the top of the pot so that it can seep back down thru the ground coffee (Fig. 118).

A perforated cup with a perforated cover holds the coffee. Thru the center of this cup passes a small tube to the top of the pot. At the bottom of the tube is a flat plate with turned-down edges or other device which supports the pipe and rests on the bottom of the pot. A small amount of water gets under this and into the pipe. The heat in the stove turns the water next the bottom to steam, and this steam, in escaping, forces the water in the pipe to the top of the pot, and raises the device slightly so that more water flows under it and into the pipe, and again steam is formed and more water forced to the top of the pot. (See Sec. 161, Suction Washers.) After being forced out of the top of the pipe, the water falls in a spray on the cover of the cup and seeps down thru the coffee back into the main part of the coffee pot. The pumping devices in percolators may differ somewhat in design, but the working principle is the same—that steam is lighter than water and can be generated in amounts which will force water up thru the central tube.

Coffee grounds must not be allowed to get into the small tube, for they will hinder the flow of the water. The holes in the cup and cover must be kept open. There is less waste in using finely-ground coffee than the coarsely-ground in percolators. A small tube brush is needed for cleaning percolators. The coffee must not be ground so fine that it will sift thru the perforations in the cup.

CHAPTER XXX

Dish-Washers, Canners and Dryers

The dish-washers (Fig. 119) have found a place in hotels and large establishments, they are still in the experimental stage for general household use.

Small machines on the market, patterned after the hotel type, are giving good results for home use. When using these machines, place the dishes in them in the manner directed and use as much water as is called for.

Some dish washers work on the plan of revolving the dishes in the water, some in forcing the water over the dishes, and others by agitation of both dishes and water.

Keep the pan washed clean. Keep all bearings properly oiled. Have the machine dry when not in use. There is least breakage in the washers which hold the dishes stationary (Figs. 119, -a, -b and -c).

One type of dish-washer has no motor; the force of the running water washes the dishes. This can only be used where the water supply is abundant and under considerable pressure. The washers equipped with paddles for throwing the water over the dishes use about a dishpanful of water for washing the dishes, and as much more for scalding and rinsing them. When well scalded in the dish-washer, the dishes will dry if the cover to the washer is left open.

214. Dish Dryer. There is a number of dish dryers on the market which hold the dishes separate from each other. Into these dryers, boiling hot water is poured, over the dishes. There is provision for the water being drained away immediately, and the heat it imparts to the dishes dries them. (Fig. 119-c.)

215. Cleaning Silver. Silver can be cleaned in an aluminum pan filled with water and soda. There are silver cleaners which are merely aluminum pans with which come directions for proportioning the soda and the water. A mixture of salt and baking soda is sometimes used, combined with a piece of zinc in an aluminum pan. The salt, soda, zinc and silver are put into the aluminum pan and set on the stove. The action of the salt and soda on the metals produces an electrolytic action which brightens the silver.

Do not use this method of cleaning on gray or colored silver.

216. Canners. Canners are devices for sterilizing fruit and other food which is being canned. The wash-boiler type consists of a boiler or kettle with a rack in the bottom to raise the jars an inch or so from its bottom to prevent the cracking of the jars. It has a cover to keep the heat uniform. The water in the canner must entirely cover the jar. This is usually called a water bath, as the jars must be completely submerged in the water (Figs. 120 and 120-a).

217. Water Seal. Water-seal canners are like the water-bath canners, except that the cover has a flange on it, the depth of the boiler, and about two inches from the sides of it. This makes a jacket of water between the flange and sides of the canner. This causes the temperature inside to rise about two degrees above the ordinary temperature of boiling water. Food can be sterilized in a little shorter time in this canner than in the ordinary water bath. It is as important that the water entirely cover the jar in this canner as in the water bath.

218. Pressure Canners. Pressure canners are made very strong and have covers which fit tight, making it possible to raise the temperature in them considerably above the boiling temperature of water, so the food may be sterilized in a very short time.

The pressure canner has either a rack or a perforated pail on the inside to raise the jars from the bottom as in other canners. It is also fitted with a steam gage which registers the pounds of pressure in the canner. Five to fifteen pounds pressure is used for canning. The amount of pressure needed and the time of sterilizing depends on the organism present. A higher pressure is an indication of a higher temperature in the canner. After the jars are filled and put in the canner, the cover is fastened down tight by thumb-screws. There is a pet cock which is kept open when the canner is first heating, to let the air be forced out by the first steam which forms. As soon as the steam begins to escape, the pet cock is closed and the temperature inside of the canner begins to rise above the temperature of boiling water (Fig. 121).

On the canner is a safety valve which is set so that the instant a certain number of pounds of pressure is reached, it is lifted up by the steam. Some of the steam then escapes, thus preventing the pressure in the canner becoming so great that there is danger of its exploding.

219. Use of the Canner. Water is put into the canner to reach to the bottom of the rack. The jars are filled according to canning directions and are set in the canner. When the jars are in, the cover is adjusted to the canner and screwed on tight so that no steam will escape between the cover and the canner. The pet cock is left open until steam begins to escape thru it as the canner is heating on the stove. When steam begins to come, the pet cock should be closed, and the steam-gage hand then begins to turn, indicating that the pressure in the canner is rising.

When the steam-gage reaches the point desired, the safety valve is adjusted so that the steam will escape should the pressure continue to rise. Until the operator knows where to set the weight to the safety valve, leave it well out to the end of the rod until the pressure in the canner has reached the desired point. Then move the weight to the point on the arm of the valve which will just keep in the steam.

Be sure the cover is properly adjusted. Be sure to exhaust the air from the canner before closing the pet cock. Keep the fire so that the desired pressure will be maintained without the escape of steam from the safety valve. When steam escapes from the canner thru the pet cock at a rapid rate, it may cause liquid to flow out of the jars.

Be certain to let the canner cool until the indicator on the steam-gage has reached zero before opening the canner. When the indicator points to zero, open the pet cock. If a heavy stream of steam starts to escape from it, close it again and wait a few minutes longer. Test again by opening the pet cock; if a very little stream of steam escapes, leave the pet cock open and wait until steam has stopped escaping from it. Now loosen the screws holding the cover in place. Partially loosen each screw. When this is done, fully loosen all and lift off the cover. These precautions are taken to prevent the operator from being burned by steam or getting hurt by the cover being lifted by the steam. It also prevents the breaking of glass jars due to sudden pressure changes.

Never let the canner cool so long before the pet cock is opened that air will rush into it, due to the vacuum which is sure to form when the steam is cooled if the pet cock is not opened. Such a condition may break the jars.

Tin cans are sealed with a device (Fig. 122) which folds the edge of the cover over the top of the can so tightly it will not leak.

220. Dryers. Dryers are devices to hold the food being dried in a thin layer so that the air can be circulated thru it freely. Sometimes they are devised to direct currents of air thru the drying material. If the air is heated, the drying is hastened (Fig. 123).

A sieve on which food is spread hung above the stove is a simple drying device and one of the most practical for home use. The heat currents rising from the stove pass thru this and dry the food.

Many dryers are constructed on this same principle, having a heating unit below and trays of food above. These trays have to be shifted from time to time, as the moisture from the lower ones rises with the heat to the upper trays, thus retarding their drying. The top trays, if too numerous, are useless on this account. Two or three seem to be all that can be used with advantage at one time in home dryers, the some machines are made with many more.

Another type of dryer has a fan device in it which forces the air thru at a faster rate than would be accomplished by heat alone. Such air should pass thru a strainer. Ordinary air, even when drawn from a clean room, carries much dust with it, and if the dust is not strained out previously, it is strained out by the food. This injures the quality of the product. Large commercial dryers provide such a strainer.

221. Care of Dryers. Dryers should be kept clean. They should not be heated enough to cook the food. Set them in a dry, airy place.

CHAPTER XXXI

Separators and Emulsifiers

222. Cream Separators. A cream separator is a device for separating cream from milk. Separation can be done best while the milk is still warm (Fig. 124).

Separators should be set in a bright, dry, airy place free from dust and dirt. Near the separator should be a convenient place for airing and sunning the tin parts which come in contact with the milk.

The base for the separator should be solid enough so that it will not shake while the machine is being operated. If set on a wooden floor, see that the boards are nailed in place, and if the floor is thin, put heavy strips to cover several boards across it. Fasten the strips firmly to the floor and set the separator on them. When the machine is set up, be sure that it is set level.

223. Different Types of Separators. There are two types of separators—one which contains discs of metal (Fig. 125), and the other which depends upon a cylinder in which the milk rotates (Fig. 124) for the separation of the cream from the skim milk. Fig. 126 shows a sectional view of the DeLaval separator.

Cream is lighter than milk, and when milk and cream are whirled rapidly, the milk, being heavier, flies to the outside of the container, and the cream stays near the center. Two pails whirled rapidly made the first separator ever used, but that was clumsy and impractical.

Modern separators consist of a pan which holds the milk, and which lets it flow in a stream into the portion of the machine which is being whirled rapidly by the turning of the wheel at the side. There is a place in the rotating part which lets the cream flow from the center into one container, and the milk flow from the outside to another.

The parts of the machine must be fitted together properly; otherwise, it will fail to do good work.

Always turn the wheel at the speed indicated for the machine with discs. If there is no speed indicated, turn as fast as needed for good separation of milk and cream. Take care not to drop and dent any of the tin parts. Adjust for the density desired for the cream.

224. Washing the Machine. As soon as milk has been skimmed with the separator, pour some water into the bowl and run it thru the separator the same as the milk.

Wash the bowl and other parts in hot water in which washing soda has been dissolved. Rinse in clear water, and then scald with boiling water. Once a week give it a more thoro washing, scrubbing all parts with a brush. Sun the parts when not in use.

225. Oiling. The mechanical parts which whirl the separator should be kept oiled. In oiling, follow the directions which come with the machine. Use a good grade of oil.

226. Whey Separator. A whey separator is a machine very much similar to a milk and cream separator. It is used in homes where much cheese is manufactured. It should be given the same care as other separators.

An homogenizer is a device used to give whole milk a consistency which is much like cream.

227. Emulsifier. The emulsifier is a device for combining dried whole milk with water, or dried skim milk with water and butter fat so that they make a reconstructed milk of almost the same composition as new milk. An emulsifier is of interest to the woman who lives in the city. Emulsifiers are used in large institutions. Some have been installed in settlement houses and public schools. They might be owned by communities where people might use a large amount of dried milk. In the emulsifier, the milk, water and sweet butter are warmed. After this, they pass thru a device looking much like a separator, but which mixes the ingredients together instead of separating them. From the mixer the milk passes over a cooling device, and is ready for use. This machine should be kept clean, and the parts which come in contact with the milk scalded out with hot water after being rinsed with cold water.

Questions for Part VIII