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Screw pumps are a unique type of rotary positive displacement pump in which the flow through the pumping elements is truly axial. The liquid is carried between the screw threads on one or more rotors. The liquid is then displaced axially as the screws rotate and mesh. In other types of rotary pumps, the liquid is forced to travel circumferentially, however the screw pump has an axial flow pattern and low internal velocities.

It provides a number of advantages in many applications where liquid agitation or churning is objectionable. Screw pumps are classified as two different types: the single rotor and the multiple rotor. The multiple rotor is further divided into timed and untimed categories. Timed rotors rely on outside means for phasing the mesh of the threads and for supporting the forces acting on the rotors. Untimed rotors rely on precision and accuracy of the screw forms for proper mesh and transmission of rotation.

Advantages

1. Wide range of flows and pressures
2. Wide range of liquids and viscosities
3. Built-in variable capacity
4. High speed capability allowing freedom of driver selection
5. Low internal velocities
6. Self-priming with good suction characteristics
7. High tolerance for entrained air and other gases
8. Minimum churning or foaming
9. Low mechanical vibration, pulsation-free flow, and quiet operation
10. Rugged, compact design — easy to install and maintain
11. High tolerance to contamination in comparison with other rotary pumps

Disadvantages

1. Relatively high cost because of close tolerances and running clearances
2. Performance characteristics sensitive to viscosity change
3. High pressure capability requires long pumping elements

There are three basic types of screw pumps:

Single Screw

The single screw pump is more commonly known as the Archimedean screw. It is quite large; typical dimensions include a diameter of 12 inches or greater, and a length up to about 50 feet. It is normally used as a water-raising pump with the screw arranged at an angle of 30 degrees. It can also be used for handling liquids containing solids in suspension with either vertical lift or horizontal transport. The design of single screw pumps allows very little fracturing of particles and little abrasion damage to the pump. One disadvantage is the considerable bulk necessary to achieve high capacities since rotational speeds are of the order of 30-60 rpm (Warring, 1984).

Intermeshing Screw Pump

The intermeshing screw pump is commonly called a rigid-screw pump. This type of pump is suitable for a wide range of sizes, and can be run at high speeds. The larger screw pumps are used for bulk handling of oils and similar fluids. The basic type is suitable for handling most clean fluids with low flow velocities and at low heads (Warring, 1984).

Eccentric screw pump

The eccentric screw pump is versatile. It is capable of handling a variety of liquids and products with high efficiency. It comprises of a rigid screw form rotor rolling in a resilient internal helical stator of hard or soft rubber with a moderately eccentric motion. It can handle viscous liquids, slurries, pastes, solids in suspension, and delicate products. This is because of the low flow velocities through the pump (Warring, 1984).

The screw pump is the oldest type of pump. The first applications, dating back to the third century B.C., included irrigation and land drainage. The screw pump is thought to have been first used in Egypt (Ewbank, 1972). After several other types of pumps were invented, the screw pump was not used as much because these other pumps could handle higher head capacities. However, later it was found that these pumps could not handle wastewater like the screw pump could. Because of this, the screw pump became widely used for such an application. The Dutch were the first to design a spiral lift screw in 1955. After this, double screw units were put into operation for flood control in the Netherlands and in municipal sewage installations in Europe. Based on excellent results from the pumps used in Europe, the trend extended to Canada and United States and are currently used today.

Here a flexible toothed rotor is used, generally made of rubber,picture 1. This is very simple in concept, being like a revolving door, but it can involve both considerable friction and significant back leakage. It cannot therefore be considered as an efficient type of pump. On the positive side, it will readily self-prime and can achieve a high head at low rotational speeds. Much will depend on the quality of the rotor material and the type of internal surface of the casing so far as both friction and durability are concerned.

Another similar type, developed recently by Permaprop Pumpen in Germany, has an endless rubber toothed belt which is driven around two pulleys; (see picture 2). As it curves around a pulley, the teeth on the belt spread apart and increase the volume between them, thereby drawing in water. The diagram shows how both sides of the chamber simultaneously pump in opposite” directions, and suitable channels in the casing direct the water. The advantages claimed by the manufacturers are, inter alia, that it can run on “snore” indefinitely - (i.e. pumping a mixture of air and water), it will readily self-prime and suck water up to 8m and lift it a further 45m under the power of a small portable single cylinder engine. It is therefore a much more versatile pump than the equivalent centrifugal pump, but it is more complicated and expensive.

Geothermal heat pumps (GHPs), often called ground-source heat pumps, have been proven capable of producing large reductions in energy use and peak demand in buildings.If the federal government set a goal for the U.S. buildings sector to use no more nonrenewable primary energy in 2030 than it did in 2008, based on previous analyses, it is estimated that 35 percent to 40 percent of this goal could be achieved through aggressive deployment of GHPs. In addition, $33 billion to $38 billion annually in reduced utility bills (at 2006 rates) could be achieved through aggressive deployment of GHPs.

The key barriers to rapid growth of the GHP industry, in order of priority:

1. High first cost of GHP systems to consumers.
2. Lack of consumer knowledge and/or trust or confidence in GHP system benefits.
3. Lack of policymaker and regulator knowledge of and/or trust or confidence in GHP system benefits.
4. Limitations of GHP design and business planning infrastructure.
5. Limitations of GHP installation infrastructure.
6. Lack of new technologies and techniques to improve GHP system cost and performance.

The following actions would address the barriers and facilitate rapid growth of the GHP industry:

1. Assemble independent, statistically valid, hard data on the costs and benefits of GHPs.
2. Independently assess the national benefits of aggressive GHP deployment.
3. Streamline and deploy nationwide programs to provide GHP infrastructure.
4. Develop and deploy programs to provide universal access to GHP infrastructure.
5. Develop the data, analysis and tools to enable lowest life-cycle-cost GHP infrastructure.
6. Expand geographic areas where high-quality GHP design infrastructure exists.
7. Expand geographic areas where high-quality GHP installation infrastructure exists.

People who have sump pumps in their homes will tell you they could not do without them.  Like many other home appliances, a sump pump requires maintenance.

It is often recommended that you do not clean the sump pump yourself but leave that task to someone who is qualified.  However, you can pour white vinegar through the unit which will eliminate most of the build up in the system.  Sump pumps have screens or openings where the water enters the pump.  These screens often get clogged, if that happens, the pump will need to be professionally serviced by a plumber.

Some manufactures recommend the sump pump be run and tested every two or three months.  I highly recommend you do that and not wait until you have two feet of water in your crawl space or basement.  If you wait and that happens the cleanup will be very expensive.  Each manufacture provides written maintenance instruction for their pump.  If those instructions are followed the pump will last a long time.

Below are a few maintenance tips:

• Fill the sump pit with water to make sure the pump is working properly.

• Go outside and check to make sure the pump is discharging properly.  Some times the pump will run but not discharge water because the screens are clogged.

• When checking the pump, make sure the float is not obstructed or stuck in one place.  It should be free floating.

• Clean the air hole in the discharge line.  If it is clogged it will not pump properly.

• Listen to the pump motor for any strange noises.  Feel the casing to see if it is warm or hot.  If the pump is whinnying or hot, stop the pump and check it out.  It is probably clogged.

• Some pumps have a battery backup.  They should be changed every couple of years.

• Make sure the pit is free of debris.  If the inlet suction screen becomes clogged, the pump will not work.

• If you spot an oily film on the surface of the water the oil seal has been breached and the pump will need to be replaced.

In general, a sump pump does not require lots of maintenance.  However, following a few simple steps will extend the life of the pump and give you the full value of the pump.

A fuel pump usually is an essential component on an internal combustion engine device, commonly seen on cars. Some engines like old motorcycles don’t require a fuel pump. They use gravity to send fuel to the engine from the fuel tank. Fuel pumps deliver the fuel from the fuel tank to the engine using low pressure mechanical pump which is mounted in the fuel tank. Some engines have two fuel pumps, a low pressure/high volume supply pump and a low volume/high pressure supply pump.
When starting the engine, you may notice that it is hard to start. You may also experience loss of power while in a full throttle situation. This may be a sign that the fuel pump is in a bad condition. It is better to check if the fuel pickups, filters, electrical connectors, and pump relays are in a good working condition before replacing the fuel pump.

Electric fuel pumps can be found in two locations. One is inside the gas tank and the other is underneath the car. This fuel pump generates high pressured fuel which is supplied into your electronic fuel injection system.
Some tools are needed in changing a fuel pump. These include the following: a replacement fuel pump, large fuel catch container, new fuel line, fire extinguisher and eye protectors (for safety purposes), socket set, open end wrench set, flat head screwdriver, and Phillips head screwdriver.

Changing a fuel pump is not a hard thing to do. It can be easily done by following these steps carefully:

1. Release the pressure first in the fuel system. The fuel injection systems functions in a very high pressure. Explosive results may happen if this pressure is not released before removing the fuel lines so it is better to put the fire extinguisher somewhere near.
2. Start the car engine then pull the fuel pump fuse in the fuse box. If your car doesn’t have a fuel pump fuse, pull the relay that operates the fuel pump instead. If done correctly, the engine will die instantly, releasing all the pressured fuel in the system.
3. Locate the position of the fuel pump. Fuel pump located underneath the car is held by a number of bolts. You will need the open end wrench in this task.
4. Remove the fuel lines from the fuel pump using the open end wrenches. Gas will surely leaks while removing the fuel lines so use the fuel catch container while removing.
5. Disconnect the wire connections of the fuel pump. There should be two wires, a ground and a positive wire. It is better to mark which is which so reconnecting wouldn’t be a problem. The wires may be held by plugs, small bolts or screws.
6. Swap the previous fuel pump with the new one. Connect the wiring and the fuel lines back. Then return the fuel pump to its position, tighten it and make sure it is not loose.
7. Return the removed fuel pump fuse or the fuel pump relay from earlier. Then start the engine and prepare for a test drive.

Your sump pump system is your home’s first line of defense in heavy rains, flash floods and other water emergencies, so it is wise to keep that system in working order. Sump pumps operate automatically and are permanently installed typically in the basement in a “sump pit” or hole in your floor, while utility pumps are portable units that plug into an electrical outlet, though gas and battery powered utility pumps are available. They attach to a garden hose for removing standing water manually. Both types of pump need to be ready to perform in emergencies.

If your sump pump is not working up to par or you need a new system installed, consider upgrading to a new microprocessor controlled switch from Wayne Pumps. “If your sump pump is as old as your house, it likely has a mechanical switch,” says Tony Ferrante, VP Sales & Marketing, Wayne Water Systems, a leading manufacturer of sump pumps. “When pumps fail, it is usually due to switch failure. Mechanical switches, like tether and float switches corrode and wear out over time.” Here are additional tips from Wayne Water Systems to ensure optimal pump performance and safety.

• Check your sump pump regularly by pouring a pitcher of water into your sump pit. This will turn your pump on.

• Make sure your sump pump can handle the maximum amount of water anticipated, measured in gallons per hour. Refer to your instruction manual for performance reference.

• It is highly recommended that you include a battery back-up system in addition to your primary pump in the event of a power outage. Protection in this time of need is crucial, to protect your home.

• Remove standing water from your home or property with a utility pump to avoid mildew damage and the infestation of insects that may carry West Nile virus.

• Utility Pumps are usually non-automatic pumps that come in various submersible and non-submersible designs powered by electric, gas or battery. For submersible utility pump, the “pump” is intended to be submersible and therefore the typical 8′ cord will be partially, as well. Do not allow water to get near an outlet as the risk of electric shock.

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• Transfer Pumps are never submersible and are used to quickly transfer standing water from one area to another, like flooded basements or to fill or empty aquariums, water gardens or water beds.

• For quick removal when the water level has reached areas of concern, make sure your utility pump and any suction attachments are accessible. Do not store out of reach, such as in a shed. Water can rise to dangerous levels in minutes. If it is high enough to reach outlets, leave the area.

• Do not stand near open drains or catch basins, especially in or near moving water. If you lose your footing, water pressure can hold you under.

By following these tips, you can keep yourself and family safe as well as prevent extreme water damage to your home and valuables.

Impellers of pumps are classified based on the number of points that the liquid can enter the impeller and also on the amount of webbing between the impeller blades.
Impellers can be either single suction or double-suction. A single-suction impeller allows liquid to enter the center of the blades from only one direction. A double-suction impeller allows liquid to enter the center of the impeller blades from both sides simultaneously. The illustration below shows simplified diagrams of single and double-suction impellers

Impellers can be open, semi-open, or enclosed. The open impeller consists only of blades attached to a hub. The semi-open impeller is constructed with a circular plate (the web) attached to one side of the blades. The enclosed impeller has circular plates attached to both sides of the blades. Enclosed impellers are also referred to as shrouded impellers. Figure 5 illustrates examples of open, semi-open, and enclosed impellers.

The impeller sometimes contains balancing holes that connect the space around the hub to the suction side of the impeller. The balancing holes have a total cross-sectional area that is considerably greater than the cross-sectional area of the annular space between the wearing ring and the hub. The result is suction pressure on both sides of the impeller hub, which maintains a hydraulic balance of axial thrust.

A sump pump is a drainage-tile system that is placed under the floor of you’re basement that channels water into a pit.

What does a sump pump do?

Some houses depending on location, climate conditions, and building structure. Have a unavoidable problem with flooding from the bottom up due to natural weather and environment conditions.
A sump pump provides somewhere for that water to go other then into your home.

How do I know if a sump pump is right for me?

If you have a serious or just annoyingly minor problem with water getting into your basement there are certain elements of your home you need to check to first identify if you have a flooding issue due to needing a sump pump, or just a overlooked minor issue that can be prevented by locating an fixing the problem.
So before assuming you need a sump pump check all drainage installed on or around your home.
Unclog all clogged gutters, downspouts dispose of runoff water at least 4 feet away from your homes foundation.
And all soil around the foundation of your home downslides at least 3 feet. *The downslide facing away from your home.
If you have a newer home make sure you don’t already have a sump pump installed.
If you still have a problem then a sump pump is right for you.

How is a sump pump Installed?

Usually a large slab of concrete is removed from the base of your home.
A large percentage of soil is also removed from underneath you’re home.
Then drain tiles, gravel, and a pit is installed in place of the concrete.

How much does it cost?

A professional normally charges around $2500 to $5000 to install a sump pump.
This being a reasonable price in comparison to the loss of value, and measure of damage of your home without the placement of a sump pump.

What are some ways to prepare for a sump pump installation?
Does your waterline run under the floor?
If so where does it run?
You might be able to find the answer to this by inquiring with a local buildings codes office. This being that usually these things are recorded upon installation and stored into files.
Think about how you may prefer your concrete to be removed being different tools may do better or worse jobs. Make inquiries about the tools to the installers being some installers will not use certain types of tools.

Will a sump pump be guaranteed to eliminate the flooding problem?

In most cases yes it will, but it depends on how serious your problem is. A sump pump gives water an alternate place to go other then straight up into your basement.
In extreme conditions this may only lessen the issue to something less threatening for your home.