ourpump.com blog

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.

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.

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.

.

• 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.

Anybody want to go for a swim in a pond of stagnant, sludgy water? No? Why, then, would we expect our fish to be happy in a tank with poor water circulation? Like its cousin the air pump, a water pump is another kind of aquarium pump that will help to create a healthy environment for your fish.

1. Filling up the tank and draining it as well. Aquariums periodically must be drained and filled back up. What better way to do this than to use an aquarium pump?
2. Filtration. Perhaps the most fundamental use of these aquarium pumps is to either move water into the filtration system, or to move the water back into the tank after filtration has occurred. The filter setup in your aquarium, along with the necessary flow rate and head height, will determine the kind of water pump you buy.
* Aquarium water pumps can either be submersible in the tank (as with powerheads) or outside of the tank in the form of an in-line water pump. Submersibles make less noise and are typically easier to set up. However, in-line water pumps are capable of generating more powerful pumping than submersibles, and also will not heat up surrounding water as the submerged pumps unfortunately can (one clear benefit of being outside of the water). For pressure filtering systems, you should use an in-line.
* For a wet/dry filter system, your aquarium water pump will be set up to move the water from your filter back into the greater volume of the tank. You can use either a submersible water pump or an in-line free-flow water pump. Once again, the in-line pump does not carry the risk of heating the water, and can even achieve a better flow rate. But you’ll have to roll up your sleeves and be prepared for some installation fun.
3. Protein Skimmers. In a separate article, we described how air pumps can be used to power a protein skimmer. Aquarium water pumps can serve the same purpose, but with greater gusto. Turbo and Venturi protein skimmers both rely on a water pump.
4. Making healthy currents. It is important in any aquarium to avoid dead pockets of no water movement. In such places where water stagnates, algae will build up. Think of a swamp. Aquarium water pumps are often used to create currents and water movement in your aquarium.

Water movement in aquariums has grown quite sophisticated over the years. Water pumps can be used to power wave makers, which can simulate ocean currents within your aquarium. Particularly if you have a reef aquarium, this feature is a vital investment; corals and saltwater invertebrate species depend upon this kind of water movement in order to feed and to get rid of waste.

As with other aquarium pumps, you can buy a water pump from pet stores and online. If you are just beginning as an aquarist, try to visit a local pet store where the staff can help you navigate the many options and make sense of the features and specifications of the water pumps. When you buy your aquarium water pump, consider the following guidelines.

* Flow rate. Flow rate is the amount of water the pump will move in an hour (measured in gallons per hour, or GPH). The water in your aquarium should be turned over roughly four times every hour; if your tank holds ten gallons, for example, then you would have to buy an aquarium pump capable of sustaining a flow rate of forty gallons per hour.
* Head height. Head height is the vertical distance from the pump to the highest destination of pumped water. Once you have figured out the type of water pump that will work with your filtration system, the head height and flow rate will determine whether or not one of these aquarium pumps will work properly in your aquarium.
* However, when buying an aquarium water pump, it’s always best to err on the strong side. Once you have bought your aquarium’s water pump, you can adjust the flow rate in only one direction: down. To continue using the previous example, buying an aquarium pump with a 40 GPH flow rate at your head height will not be able to compensate for plumbing factors that can decrease flow rate of a pump. Instead of buying the aquarium pump that just satisfies your flow rate and head height needs, buy one that exceeds the requirements.

Typical situation where a ram pump may be used

Momentum building up

Shock wave pushes water into delivery pipe as impulse valve shuts

Water enters the ram from the thick drive pipe and runs out of the impulse valve, which is held open by a spring (or weight in larger pumps). As the momentum increases, the pressure of the water will drag the impulse valve shut. This creates a shock wave inside the ram body, pushing water past the delivery valve (a non-return valve). As the pressure subsides the impulse valve opens and the cycle begins again. This takes place more than 100 times a minute, depending on the head pressure and tuning of the impulse valve, and each pulse pushes up a small quantity of water through the thinner delivery pipe. The air chamber cushions the flow. The tiny snifter valve below the chamber allows a small quantity of air into the air chamber with every pulse to replace air lost into the deliver pipe. A small squirt of water will come out on the recoil.

If you have a water supply (spring, brook or river) below the point where you need the water, and the source is higher than the lowest part of the property, then a hydraulic ram pump may be the solution. Hydraulic ram pumps are powered by a portion of the water running through it. If the cost of a commercial pump puts you off, or the water volume is too little to operate the pump, you can make one to suit your conditions at very little cost.

It is made with 1″ stock brass compression fittings, some inner tube for valves, a few nuts and bolts and some copper pipe, some of which was flattened to use for valve seats. It is held down onto some concrete embedded I-beam with exhaust pipe brackets, cushioned by inner tube. The supply pipe is 3/4″, the delivery pipe 1/2″ and the expansion chamber 1″ diameter. There is a small amount of soldering involved. It pumped a little over 10% of the water a few dozen feet up, making it as efficient as commercial pumps. The small size works with the limited amount of water I have. The basic principle for building it came from a book, but I scaled it down, and made some changes, and avoided welding. The measurments were roughly calculated by rule of thumb: “that looks about right”. In this picture the pump is disconnected from the pipes. It only cost a few GB Pounds for the bend and ‘T’s, the 1″ pipe piece needed was recycled from a skip (dumpster).

The treadle pump is based on a design developed in the 1970s by Norwegian engineer Gunnar Barnes. It can be made locally. A group based in the United States, IDE, International Development Enterprises, has created programs in different countries.

The program in India won an Ashden Award in 2006 for using local sources of energy to improve quality of life. Last year the Bill and Melinda Gates Foundation awarded IDE 27 million dollars. The money is to be used to expand small irrigation projects to the other half of India’s 28 states.

The treadle pump is easy to build from bamboo or other wood and two metal cylinders with pistons. The pistons go up and down as a person stands on lever devices — treadles — and uses a natural walking motion.

How many hours a day the pump needs to be operated depends on the season and how much water is needed for crops. It could be two hours a day. It could be seven hours a day.

Small children sometimes stand with their parents on the treadles. Everyone in the family can take turns operating the pump.

The Acumen Fund is a nonprofit group that invests in business projects to fight poverty. It studied the effects of treadle pumps in the Indian state of Uttar Pradesh. Uttar Pradesh has three treadle pump manufacturers and more than 73 thousand pumps.

Acumen reported that families using them ate more vegetables, because they were able to grow more to eat and to sell. Many of these families also drank more milk, because they bought a cow with their added earnings. Men with treadle pumps often no longer have to leave the farm to seek extra work in cities.

The pumps can also improve education. Farmers often use their extra earnings to buy books for their children or to pay for schooling.

A farmer in Zambia said he hoped to have enough money in three years to buy a diesel powered pump. Then he could grow more crops over a larger area.

But the world economic crisis has had an effect on some farmers. IDE executive director Zenia Tata says some who were able to buy diesel pumps now do not enough money to buy fuel. So they are using their treadle pumps again.

This submersible pump is from Taizhou Kaili Pumps Co., Ltd. The company established in 1994,  is one of the largest pump manufacturers in Zhejiang China. Since established, The “XIONGLI” water pumps have been honored as “the famous product of Zhejiang Province”, “new millennium high quality science and technology symbol product of Zhejiang” and “Reliable and credible enterprise” etc.
Taizhou Kaili Pumps CO., Ltd won the production license of the national industrial products in 1999, gained the popularizing license from the Ministry of Agriculture in 2000 and past the international quality system ISO9001 and CCC authentication in the same year. People’s Insurance Company of China has taken the Quality Assurance in 2002.

This submersible pump has been Approved by CE.This series pump’s model is QDX, QX series, consists of pump, mechanical seal and motor. Pump is at the bottom part of pump, which is adopted centrifugal impeller. Motor which is monophase or triphase is at the upper part of pump and seal is used where pump and motor combine, which is a kind of doubleend mechanical seal, O rings are applied to all static joints.

This series pump is small and light, which is widely used in countryside for elevating water from well, irrigation, sprinkling and domestic water supply, and also used in draining off water for fish pond and building site.

If you want to buy such submersible pump, you can click the link above to contact the company, or have a look at other pumps .