Models

In-Sink-Erator is the company to beat. Lots of companies offer disposers, but In-Sink-Erator makes the vast majority of disposers sold in this country.

Grainger sells In-Sink-Erator. Lowe's offers GE and In-Sink-Erator. Home Depot offers In-Sink-Erator. Sears, of course, sells its own brand, Kenmore -- which is actually In-Sink-Erator with a bit of badge engineering.

Badge engineering is really easy here, because disposers have a plastic shroud around the grind chamber to help muffle the noise. Kenmore models have their own plastic shroud, not only a different color than In-Sink-Erator models, but a different shape as well. Standing on the shelf, they look totally different -- until you start comparing the parts other than the plastic shroud, which are identical. The sink flange says "Kenmore" instead of "In-Sink-Erator".

There are some benefits to this near-monopoly situation. In-Sink-Erator offers several accessories, and when you decide you need one they are really easy to find. The rubber flap doohickey that you jamb scraps through may eventually wear out, and you can get a new one at any place that sells In-Sink-Erator models.

Finally, note that the sink flange attachments that In-Sink-Erator disposers use are the same, regardless of which model you get. And they've been the same for years. If you ever have to replace a unit, you may learn to appreciate that standardization. Y'see, installing the flange into the sink is the hardest part of installing a disposer.

Once in, sealed, and tightened down, you just hold the disposer up to it and turn a lock ring. It's in, you just need to connect the outlet pipe. So, if the old disposer is an In-Sink-Erator, you don't even have to fool with the flange; just drop the old unit, slap in the new, and save the new flange parts as spares. And you can upgrade from a low cost unit to a better unit just as easily.

The materials used in the construction of the grinding chamber of a waste disposer are the most important consideration in the selection of the disposer.

These materials are subjected to water and garbage, and they are also allowed to air dry between uses -- a sure-fire recipe for corrosion. If you buy the wrong disposer, some time down the road it'll be corrosion in these parts that forces you to buy another disposer. If you buy the right disposer, it should last basically forever; they are only operated a matter of seconds at a time, it would take many, many decades to actually wear out the bearings or whatnot.Allow me summarize the various materials you're likely to find used in wet areas of a disposer:

• Stainless steel: You'd like as much SS stuff in here as possible. Anything made of SS is likely to outlast the motor bearings, which probably means 100 years or more. A lifetime at least.
• Plastic: There are a couple of types of plastic used in disposers, but any one of them is actually a pretty good material. They won't corrode, and if properly designed should last a good, long time. Eventually plastic will dry out and crack, but without being subjected to sunlight this should take longer than we would be concerned about. One thing we might be concerned about is hot water; what comes out of the tap is not likely to be a problem (unless your water heater is set waaaay too hot), but if you make a habit of pouring pots of boiling water down the drain you could stress plastic parts. Since your waste piping is probably PVC, dumping boiling water down the drain is not a good idea anyway; always try to have the cold water tap running while pouring out hot water, and preferably pour a little cold water into the hot water before pouring the mixture into the sink.
• Galvanized steel: Galvanizing, as applied inside a waste disposer grind chamber, merely means the steel won't rust until you get the disposer home and install it. The first time you actually grind up something, that galvanized protection will be gone. Galvanized steel parts will be covered with rust in a matter of weeks after installation, and will fail completely due to rusting through within a few years. This material is crap, folks, and any company that uses it in a waste disposer should be ashamed. I might add that I have mentioned to several other engineers that disposer turntables are often made of galvanized steel and they simply didn't believe me; it is clearly an unacceptable material for the application, and they couldn't believe that any company would actually resort to using it.
• Pot metal: This is the stuff that cheap cast metal parts everywhere are made of. They are usually either plated or painted, since they will be quickly covered in white powdery corrosion if left bare. With a little age they start to corrode anyway, and the corrosion causes the plating or paint to blister up in unsightly bubbles. Such parts often look really bad, but they can last a good long while because they can be cast fairly thick so it takes many decades to corrode through them.

Now, when selecting a waste disposer, there are two reasons to be choosy about the materials in the grind chamber. The first, and most important to us engineers, is durability, and for this reason we would appreciate a machine in which every part that comes in contact with water is made of stainless steel or plastic. The second reason, and the one that many homeowners find important, is that we want the machine to look nice; when you peer down into the drain, you want to see nice, clean, shiny metal parts rather than a dark, dank hole full of rotting metal and germ-infested pits and crannies. For this second reason, it's nice to have the parts that are visible when looking down the drain to be stainless steel; everything that isn't visible is unimportant.OK, let's talk about the components in the waste disposer itself. Here's a simplified drawing of the machinery involved:

Here's a rundown of what you're likely to find in the waste disposer market:

Flange: The flange will almost always be made of stainless steel, because it's so plainly visible in the sink. In some really cheap models, the part may be made of plastic with a thin veneer of stainless steel up on top where it shows; you can easily see plastic down the sides within the hole, surrounding the area where the plug is inserted. Cheap, but it actually works OK.

In-Sink-Erator offers their sink flanges in white and almond enamel as well, for matching your decor. I suspect the enamel is over top of the stainless steel part.

Lugs: For some reason, the lugs almost always seem to be made of stainless steel, even in the cheapest models. It might be just so they can write the words "stainless steel" on the side of the box somewhere, hoping that nobody will notice that the more important parts are cheap junk.

Turntable: You really want this part to be made of stainless steel, but the cheaper models use galvanized steel here. Avoid such models.

Shredder ring: You want stainless steel here, too, even though this part isn't quite as visible from above as the turntable -- but once again, cheaper models will have galvanized here.

Chamber: On top-end models, this housing is made of stainless steel. On most other models, this housing is made of plastic. Either one seems to work fine. It's really difficult to see this thing from above without inserting a mirror in the hole.

Lower chamber: The lower half of the grind chamber -- the portion below the turntable -- and the upper end of the motor casing may, in fact, be one and the same part. This part is typically made of either molded plastic or cast pot metal. Plastic is better because it won't corrode, but one must admit this isn't too important; the cast pot metal part will probably last for decades, and nobody can see how yucky it looks without taking the outlet pipe off.

The bolt that holds the turntable to the motor shaft always seems to be stainless steel -- when there is a bolt. On really cheap units, the galvanized steel turntable may be welded onto the shaft.

The drain plug -- not shown in the drawing above -- usually seems to be plastic, which works OK. In-Sink-Erator offers a plug made of plastic and stainless steel as an accessory. And, like their sink flanges, these plugs are also available with white or almond enamel on the metal.

Here's a couple of tricks to watch for:

When you look down the hole on the In-Sink-Erator model 444 (and the similar Kenmore 60563), the turntable appears to be stainless steel. However, if you look in through the outlet you'll see that the stainless steel disc is attached to a galvanized flange underneath. So it may look good from above, but you still may have a rust-related failure of this part down the road. Fortunately, it's not too difficult to get parts for In-Sink-Erator disposers, and it's not too difficult to replace that turntable. The top-end In-Sink-Erator models with model numbers that end in SS have the stainless steel disc attached to a stainless steel flange -- but the lower half of the grind chamber still appears to be pot metal.

There are several types of metal called "stainless steel", and some of them will not attract a magnet at all while others will attract a magnet weakly. Other than the center bolt, the stainless steel in the In-Sink-Erator models will attract a magnet strongly. In fact, you can't tell the stainless parts from galvanized parts with a magnet. This makes it pretty difficult to tell stainless steel from galvanized at all. Not much advice I can offer here, other than to suggest you look at some parts that you know are stainless steel and other parts that you know are galvanized until you are practiced at telling the difference. The stainless steel seems to always have a bit more tan in its color.

It won't be easy figuring out which parts are stainless steel by reading the box, either. Grainger, which sells In-Sink-Erator models, has a little chart in their catalog listing which parts are stainless -- but most retail stores are nowhere near as helpful. Some models claim they have "Stainless steel grinder elements" -- but what does that mean? Does that mean that all of the grinder elements are stainless steel, or does that mean that at least a couple of the grinder elements are stainless steel? And do they consider the turntable and the chamber to be grinder elements, or just the shredder ring and lugs?

Making the important parts of a disposer out of good materials would only add a couple of bucks to the cost. However, the boneheads in the marketing departments of these companies have apparently decided that if you want good materials, you also want mucho horsepower. Hence, finding a well-built disposer with less than 3/4 horsepower is a challenge, and of course the added power runs up the cost. My recommendation would be to pay the extra, even if you don't want or need the power; you really want the good materials.

Residential waste disposers are generally available with 1/3 to 1 horsepower motors, with commercial units having even more power.  Really, it's hard to imagine any of these power options being a problem; 1/3 horsepower is plenty for chomping up everyday food scraps, and if you need more power than that you might want to rethink what kinds of junk you're shoving down the hole.There are, in fact, two general types of disposer: continuous feed models, and batch feed models.  Most models you're likely to find are continuous feed models; the idea here is that you run the water and start the disposer running before you put any scraps in the hole.  In other words, the unit is not designed to have to start from stationary with scraps in the disposer.  Do you feed the scraps in while it's running?  Not likely; most people put it in the hole first, then hit the switch -- and this is how disposers get jammed.  Fortunately, disposers include a breaker that will trip if the motor gets jammed, and some include a wrench that you can stick in the bottom to manually turn the rotor.  Some of the upper-end models even include an auto-reverse feature to clear jams.

The batch feed models are intended to be loaded before starting.  You can tell these models by the way they are operated; the plug must be inserted into the drain and twisted to start the disposer.  Perhaps a good safety feature; you theoretically cannot have your hand in the disposer when it's running.

Regardless of the type disposer, you probably don't care about the power as much as you care about the starting torque or stall torque.  Unfortunately, nobody advertises their stall torque.  Even if they did, you'd have to check the diameter of the turntable to be sure you're comparing apples to apples; a larger turntable requires more torque to provide the same force at the edge where the shredder ring is.

Now, to throw a really big monkey wrench in the discussion: there are two general types of motor used in waste disposers.  Most have split phase induction motors, and you can tell these by the rpm written on the box: 1725.  However, there are also disposers with commutator motors, and these generally spin much faster; the ones made by GE are rated at 8000 rpm.  Commutator motors are considerably smaller than induction motors, although that might not be apparent underneath the sound shielding surrounding the unit.

There are more differences, though.  When a motor turns faster, it doesn't require as much torque to develop the same horsepower, so a motor that turns 8000 rpm can have less than 1/4 the torque of the induction motor with the same horsepower rating.  That's not a problem, though, for two reasons.  First, since the commutator motor turns faster, it can be made with a considerably smaller turntable and still move the scraps through the shredder ring in a hurry, and a smaller turntable means less torque needed.  Second, commutator motors inherently have a lot more starting torque than induction motors -- and, as mentioned above, starting torque is where it's at with waste disposers.  The long and short of it: either type motor seems to work pretty well at disposing of waste.

Commutator motors -- especially ones with permanent magnets -- are also considerably more energy-efficient than induction motors.  That's totally unimportant here, though; a waste disposer probably uses a quarter's worth of electricity in its lifetime.  If you don't believe me, look at it this way: a 1-horsepower motor will draw about one kilowatt of electricity.  If you run it for an hour, under load (not just spinning with nothing in it), it'll use one kilowatt-hour of electricity, which costs less than a dime.  Now, think about how long it would take you to put an hour's operating time on a disposer.

Your garbage disposal piping probably looks something like this:

1. 1 - tailpiece
2. 2 - end outlet tee
3. 3 - P-trap (2-piece assembly)
4. 4 - adapter
5. 5 - drain pipe (into wall)

Parts of this illustration are rotated around so they appear in line on this two-dimensional drawing; in reality, the trap and the drain pipe into the wall would be arranged toward the back wall behind the sink, or into your screen in this illustration.Note there are actually two types of piping involved here.  Items 1-3 are "drainage system" components, and they typically are 1-1/2" OD, either chrome-plated brass or white plastic, with very thin walls and connected together with compression fittings.  The line going out, item 5, is Schedule 40 or DWV PVC piping, which is 1-1/2" ID, fairly thick wall, and glued together with PVC cement.  Item 4 is an adapter that is glued into the end of the PVC pipe and provides a compression fitting for connecting the P-trap outlet.

Here's what the innards of this part look like:

As you can see, it's not just a simple tee.  There is a partition in the middle, and it forces all the drainage from either sink through a half moon-shaped passage that's only half the size of the full pipe.  Hence, neither sink drains particularly fast, even when the pipes are clean.  And it's pretty easy to get the pipes stuffed up in this area.  Worst of all, whatever you toss down the waste disposer has to get crammed through that tiny passage while making a really sharp turn.There is another type of drain for a pair of sinks called a "center outlet tee", in which the drains from both sinks turn towards each other and there's a tee in between with an outlet downward.  It has the same problem.  But the center outlet tee is not commonly used with waste disposers, because it's more difficult to get the pipes to line up with the outlet on the disposer.

Fortunately, it's really easy to fix this.  The idea is to provide each sink with its own P-trap, then plumb the drain lines together back at the heavier pipe into the wall using a wye connector instead.  Wye connectors have big open passages through them.  To illustrate:

Item 1 is a "disposer elbow".  They come with a new disposer -- but if yours was installed by a professional, that part probably stayed on the truck or got thrown away.  You can buy them wherever waste disposers are sold.  They are typically black plastic for some reason.Item 2 is a tailpiece -- but you'll need a longer one than the one that was in there, so you need to buy a new one.  They typically come in 6" and 12" lengths, so make sure the one you buy is long enough; they are intended to be cut to length anyway.  Alternatively, you can keep your old tailpiece and buy an "extension", but as long as you're in there the new tailpiece is the neater way to go.

Item 3 is a new P-trap assembly, essentially similar to your old one.

Item 4 is a 1-1/2" wye.  Iit needs to be installed in a flat plane so all connections to it are horizontal.

Also,  you will need two adapters for this assembly.  Note that some adapters are made to be glued onto the end of a pipe, while others are made to be glued directly into a fitting such as the wye used here.  If you get the first type, you will need two short pieces of 1-1/2" pipe to attach them to the wye.

You'll also need to buy a disposer elbow if you don't have one, a tailpiece, a P-trap, two adapters, a small can of PVC primer and a small can of PVC glue.  You will also need a hacksaw.

Whenever you cut off a PVC pipe, you need to make sure you're leaving about an inch for gluing a new fitting on.  And when connecting up P-traps, you need to make sure that all the parts can reach each other.  Note that the outlet end of a P-trap is also intended to be cut off if it's too long.  Also remember that it's a simple matter to loosen a disposer's mounting lock ring and rotate the disposer around, which will realign its outlet connection.

When you get all this connected up, the drains will work much better since there is a full pipe diameter from each sink.

Buying a Garbage Disposal

Buying a garbage disposal is not something homeowners have to do very often. But there are many good reasons to consider buying a garbage disposal. They cut down on the amount of garbage you send to the landfill each week. There’s less old food left sitting in your trash can to stink up your kitchen. And a garbage disposal can help prevent your sink from getting clogged up by any food that finds its way down the drain.

When buying a garbage disposal, the first consideration are your local laws and regulations governing disposals, especially if you have a septic tank. In many areas, there are strict codes regarding the types of garbage disposal you allowed to have, and how they must be installed.

If you are simply replacing a worn out unit, you don't have to be too concerned about this first step, but there may be new regulations that you are not aware of. You should certainly check with local officials if your home has never had a garbage disposal; some areas still restrict their use.

Most garbage disposals will last for 10-15 years, but once the in-sink unit does go out, the convenience of a disposal will soon be missed. If you find yourself without a working garbage disposal, you are likely asking yourself: What should I consider when buying a garbage disposal?

Many garbage disposals come with 1/3 horsepower motors, which are generally suited to the workload in an apartment or single-family home. However, the newer ultra garbage disposals are also available in ½ horsepower and 1 horsepower models. When you are considering buying a garbage disposal, you will want to factor in how much use it will get. A larger home with a large family will require a stronger motor.

Invest in a unit that delivers at minimum ½ horsepower; one of lesser power can get stuck easily and will likely need replacing after only a few years.

Another consideration is design. When buying a new garbage disposal, check to ensure that it has a dishwasher connection. This design allows food particles from the dishwasher to be flushed away through the disposal system. If looks play a part in your decision, many new garbage disposals are made of gleaming stainless steel for streamlined looks - and for durability.

Most garbage disposals fit the standard drain outlet. They are either hard-wired or plugged into a 120-volt box or receptacle. The most common disposals are switch-activated, but there are 'batch-feed' models that start when you insert and turn a special drain plug. Additionally, local safety codes may determine the distance a switch must be located from the sink; the farther away, the safer.

Keep the Noise Down

A disposal will never be whisper-quiet and some garbage disposal units are quieter than others. So, when buying a garbage disposal, make sure to ask about the noise-level of each model and, under certain sinks, such as stainless steel, they can be quite noisy if not insulated.

Buying the right garbage disposal will not only help you work in the kitchen more easily and efficiently. It will also help to keep your kitchen cleaner.

Added features should also be considered when buying a garbage disposal. Many people choose to pay a bit more to get a super quiet disposal, while others find such elements as corrosion protection shields, overload manual reset buttons, self-service wrenches and anti-splash baffles to be important features.

Sometimes, a garbage disposal will get stuck. And, most of the time, you won’t want to have to stick your hand down there. Get a garbage disposal with an auto-reverse feature, which will help keep the blades from getting stuck.

Major garbage disposal companies put out brochures about their products; pick up a few at your local hardware store to review at home, and ask a few questions of the appliance personnel while you are at the store.

They have probably developed a good working knowledge of the different types and brands, and their expertise could save you some money. Reviewing the length of warranty that covers your new garbage disposal is, of course, a good idea.

 

History

Invented by InSinkErator founder John W. Hammes, a Racine, Wisconsin architect, was first to solve one major inconvenience: disposing of food scraps. In 1927, he built the first food waste disposer in his basement workshop. After eleven years of testing and development, InSinkErator Manufacturing Co. was established, making and selling 52 disposers in 1938. A slow start, to be sure — but an auspicious one.

The device first became widely popular in upscale kitchens of the 1970s and 1980s , yet remains very rare in European countries, due in part to greater promotion of composting kitchen waste. Concerns over environmental impact weakened its popularity, but kitchen designers and plumbers confirm the renewed appeal of the food-waste-grinding and -liquefying apparatus that lives under the sink.

Video- Goodbye To Garbage (circa 1950s)

Install a Garbage Disposer, Step by Step

The household garbage disposer is easily one of the Twentieth Century's greatest marvels. This one piece of kitchen equipment single handedly revolutionized both the cooking experience and the food waste removal industry.

A monster underneath the sink, it literally rips food waste to shreds and allows it to flow down the drain. If you don't have one, what have you been waiting for? Once you install one of these incredible machines, you'll wonder how you ever got along without it.

Whether you're replacing an old garbage disposer or installing a new one, it's an easy job. You don't need to be a master plumber or a licensed electrician to complete the job effectively. It does help if you know a little bit of each, but it's not necessary. That's what we're here for.

One prerequisite for installing a garbage disposer is a dedicated outlet under the sink. It needs to be protected by a 120 volt, 20 amp circuit breaker. An important note - a GFCI outlet will not allow the disposer to work. It must be a regular outlet. Turn the power off to the outlet before you begin, for safety.

Some tools you will need for this job include:

* A bucket and some rags
* Plumbers putty
* Putty knife
* Screwdrivers
* Hammer
* Wire strippers
* Wire nuts and electrical tape
* Pipe wrench or tongue and groove channellocks

1. After cleaning out everything under your sink, the first step is to remove the existing strainer from the sink. Under the sink, place the bucket under the "J" trap. Use the pipe wrench or channellocks to loosen the slip nuts and remove the "J" trap. Dump the water in the bucket.

2. With the "J" trap removed, look for the large nut that holds the strainer in place. Remove the nut.

3. Remove the strainer and clean up any old plumbers putty that was left behind. You may need to use the putty knife to pry the strainer up to remove it. It's important that the sink be totally clean of old putty and debris.

4. The next step is to open the new garbage disposer and install it. The first piece you'll need is the sink flange and mounting assembly. The mounting assembly consists of an upper mounting ring, a lower mounting ring and the mounting bolts. Take a nice amount of plumbers putty and form a ring around the drain. Take the sink flange and set it in the drain. Press it down slightly onto the putty.

5. Under the sink, take the gasket and mounting ring and slide them up the flange. You may need a second pair of hands to keep the flange stable on the top side. There should be a snap ring that you can connect to the flange to keep the gasket and ring secure.

6. Tighten the mounting bolts to bring everything together. There are three bolts, and it's important to tighten them evenly through the process. As the mounting assembly tightens, plumbers putty will squeeze out from under the flange in the sink. That's OK - simply wipe the excess away.

7. Now it's time to wire the disposer. On the bottom side of the disposer you should see 1. a red reset button, 2. a flywheel turning wrench hole, and 3. the cover plate for the electrical connections. Remove the cover plate. You should see a trio of wires - a black, a white and a green (or bare copper in some disposers).

8. The garbage disposer kit should include the cord and plug, so remove it from the box. The wires should be pre-stripped, but if they're not, use the wire strippers to remove about 3/4" of insulation. The side of the disposer should have a hole with a romex connector already in place. Slide the cord through the hole so that the black cord sheath is under the connector's metal. Tighten down the bolts on the romex connector to hold the wire in place.

9. Use the wire nuts to make the necessary wire connections (black to black, etc.). Secure the wire nuts with electrical tape and neatly stuff the wires back into the chamber. Replace the electrical cover.

10. If you do not have an installed dishwasher, you can proceed to the next step, but if you do have one, then there's an extra step. On the side near the top of the disposer you will see a close-ended tube coming out the side. That is where the dishwasher inlet line gets hooked up to. Simply take a screwdriver and hammer and chisel out the plug. It will usually fall into the disposer, so just turn the disposer over and the piece of plastic will fall out. If you have no dishwasher, or if you have the mobile kind that hooks directly up to the faucet, then leave the plug in place.

11. Now it's time to mount the disposer. Under the sink, line up the disposer with the mounting assembly. You will see where the three "ears" on the disposer should lift into. Once the "ears" are into the assembly, turn the disposer to lock it into place. It could take a few tries and the disposer may get heavy, so just take your time and don't get frustrated. You will feel it lock into place. You will still be able to slightly turn the disposer, but everything will get tightened down at the end.

12. Next connect the plumbing. You may need to turn the disposer slightly to line everything up. If you have a dishwasher, the drain line gets connected to the inlet port that you knocked out earlier. Odds are the "J" trap you removed earlier will not line up with the garbage disposer, so you may have to cut some PVC plumbing pipes to make everything fit correctly. Be sure to use the nylon washers at each lock nut.
Note - When connecting the pipes, make sure you slide the lock nut on the pipe first, then the nylon washer.

13. Connect the plumbing and make sure all the lock nuts are tight and that the disposer line is tight. Near the mounting assembly is a rotating cam collar. With a screwdriver or wrench for leverage, tighten the collar down. This will lock the disposer into place and solidify the installation.

14. Now check for leaks. Turn the faucets on and let water flow through the disposer. Inspect every locknut and seal for leaks. Tighten anything that needs it. Turn your dishwasher on and make sure the connection to the disposer doesn't leak. If everything stays dry, you're good to go.

15. Turn the power back on to the under sink outlet. Plug the disposer into the outlet and with the water running, hit the switch. You should hear the beautiful humming of your new disposer.
Note - Never run the disposer without the water running.

Types of Garbage Disposals

The most common is the continuous-feed version; once the unit is turned on -- usually by a switch on the wall resembling a light switch -- it continues to run and grind food until switched off. Water should always be kept running through the drain when the disposal is switched on to prevent damage to the blades.

 

With a continuous feed garbage disposal, there’s no switch-flipping required. These units will start working as soon as you push waste, and sometimes other things, down into them. While this might seem very convenient, it can be dangerous, especially if you have children in your household.

 

A continuous feed model can also be operated by an air switch instead of a standard electric switch. An air switch is a small button on the counter or sink which, when pressed, delivers a puff of air to a control unit mounted under the sink. The puff of air makes the control unit start or stop the unit. The main benefits of an air switch are convenience and safety.
An air switch is more convenient, because it can be mounted right next to or even on the sink itself, and it is safer because being non-electric, it is safe to touch with wet hands.

 

A batch feed garbage disposal will only work if there is waste in the disposal. And the motor won’t start until you insert a turn a special drain plug. The other benefit of a batch feed model is that the cover keeps foreign objects such as cutlery falling into the unit while it is running. Such accidents can damage the unit, and nearly always ruin the item dropped in too. A batch feed model would seem to be the safest choice for those who have children.

 

Some dishwashers are equipped with a small built-in garbage disposal unit which removes the need to pre-wash dishes.

 

Mechanism

 

A high-torque , insulated electric motor spins a round, horizontal turntable above it. The turntable is surrounded by a shredder ring, which has sharp slots. The food waste sits on the turntable, and through centrifugal force is forced to its perimeter and through the shredder ring. The turntable has a number of swiveling lugs — similar to little dull blades — attached to its topside, which assist in forcing the waste through the shredder.

 

Some high-end domestic disposals, like their commercial counterparts, also have a blade which revolves under the turntable called an undercutter. This blade chops the ground waste even finer, and also snips any fibrous material which could cause a drain clog. Disposals with undercutters can handle fibrous waste such as artichoke leaves which cannot be successfully ground in a standard disposal.

 

Another higher-end feature is automatic reversing. By using a slightly more-complicated centrifugal starting switch, the split-phase motor starts in the opposite direction with each new start. This helps the user overcome minor jams. Tougher jams can often be cleared by manually turning the motor using a hex-key wrench inserted into the motor shaft from the bottom of the disposal.

 

Some newer garbage disposals run completely on water pressure and not electricity. These garbage disposals require no external power, and completely eliminate the chance of electric shock. They also use a different mechanism. Instead of a turntable and grind ring found in an electric disposal, water powered disposals have an oscillating piston with blades attached to chop the waste into fine pieces. Because of this cutting action, they can handle fibrous waste and even a glass bottle, although of course this should be avoided in practice.

 

Another advantage of a water-powered disposal is that if an item of cutlery accidentally falls in, no harm comes to it because the blades just stop. One downside of a water-powered disposal is that they take longer than an electric disposal to dispose of the same amount of waste. They also need quite high water pressure to function correctly. If such water pressure is not available, an electric disposal is a better choice.