L A N D Y S C R E W P U M P S
L A N D Y S C R E W P U M P S
WIDE APPLICATION POSSIBILITIES
Applications for the screw pump are countless:waste water treatment plant influent pumpingstationswaste water treatment plant intermediatepumping stationsreturn sludge pumping stationsirrigation projectsdrainage projectsreclamation of wetlandscirculation within aeration systemswild water tracks in fun parksindustrial applicationsstorm water applications
INTRODUCTION
This leaflet gives an overview of the services and products of Landustrie Sneek BV regardingscrew pumps and screw pump installations.Landustrie has broad experience in this field. For nearly 100 years Landustrie has designed,manufacturered, supplied, erected and main-tained many types of screw pump configurations.Since the early eighties Landustrie has hadavailable a fully automated screw pump selectionprogram which can be used to select theoptimum screw pump for a particular application.The program is based on a large number of tests,with an equally large number of variables, in theLandustrie test facility. The accompanyingcalculation method has, for several of our orders,been approved by Germanische Lloyds.In addition, Landustrie has developed over manyyears their specific pump knowledge base, whichis continuously updated by means of R&Dactivities and the purchase of the latest techno-logy – for example their computer program usingFinite Element Analysis methods. This knowledgeand experience ensures Landustrie’s place asone of the leading manufacturers in the world ofscrew pump installations.
PRINCIPLE OF THE SCREW PUMP
The principle of the screw pump is an inclinedtube, provided with blades, which by rotatinglifts the medium to a higher level.
CROSS-SECTION Z-Z
TERMINOLOGY OF THE SCREW PUMP
The picture shows the most common definitionsregarding screw pump installations
LANDY SCREW PUMPS
Screw pumps and screw pump installations ingeneral are characterized by the followingfeatures:
open, clog-free, simple and robustconstructionhigh efficiency, low maintenance, lowoperational costshighly reliable, long lifetime and virtually nowear (no spare units required)automatic adjustment of the pump capacityas a function of the incoming flowoperating in a wide range, with a capacityfrom 10 to 11.500 l/s and lift from 0 to 25 mchanges in the capacity are easy and, ifnecessary, stepless insensitive to supply conditions and also(because of the low rpm) no problems withcavitation
OPEN, CLOG-FREE, SIMPLE AND ROBUSTCONSTRUCTION
Depending on the medium (in most cases raw waste water) several kinds of contamination can occur. The screw pump has an importantadvantage, which is that due to its openconstruction, screenings plant can, if required,be situated after the screw pump, resulting inlower civil costs of the total installation.By means of its advanced screw pump selection program, Landustrie is capable ofselecting screw pumps which, in many cases,will have two flights. This offers advantages inrespect of less deflection because of the lower bending moment, lower welding tension, and lower resultant forces on the civil construction. This in turn will allow biggerlifts. As a standard, Landustrie, based on nearly a century’s experience, allows for abending moment of 20 N/mm2 maximum, and a maximum deflection of L/2500. The actual tensions can be ascertained byinputting the data into our Finite ElementAnalysis program.All selected screw pumps can be supplied in either a coated steel or stainless steel version in AISI304 or AISI316. Other exoticmaterials are also possible.
Cross-section Z-Z Chute point
Max.pumping
point
Touch point
Fillingpoint
D = DiameterJ = No. of flightsN = SpeedS = Pitch
L = Flight lengthH = Nominal liftF = Tension� = Inclination
L A N D Y S C R E W P U M P S
HIGH EFFICIENCY, LOW MAINTENANCE,LOW OPERATIONAL COSTS
Because of the contamination in the medium, the efficiency of screw pumps for thisapplication will be much higher than for othertype of pumps. Moreover, the screw pump isideally suited to cope with variations in theincoming flow whilst working at a nearlyconstant efficiency (see under automaticadjustment of pump capacity). Also, the lowernumber of revolutions of screw pumps adds tothe relatively high efficiency of the overallinstallation.Because the complete screw pump installation is built up from an electric motor, gearbox, upperand lower bearing, the maintenance is limited toa yearly oil change and periodic checking of allgreasing points. All these factors lead to verylow operational costs for Landustrie screw pumpinstallations.
HIGHLY RELIABLE, LONG LIFETIME ANDHARDLY ANY WEAR (NO SPARE UNITS REQUIRED)
The robust construction of the screw pump body and both bearings, the use of standardcomponents such as electric motors andgearboxes at low revolutions gives the screwpump a unique reliability record. With intensiveuse a lifetime of 20 years is normal. Even screwpumps which have been in operation for morethan 40 years occur quite regularly. An additional advantage of the extreme reliability is that no spare unit needs to beconsidered at design stage.
AUTOMATIC ADJUSTMENT OF THE PUMPCAPACITY AS A FUNCTION OF THEINCOMING FLOW
The capacity of the screw pump is automaticallyadjusted in the event that the incoming flow islower than the screw pump capacity. When theincoming flow is greater than the pump capacity,the discharge will be limited to the screw pumpcapacity. Because of this equable flow regime, a screw pump is extremely suitable as aninfluent pump for a waste water treatment plant,as hydraulic overloading is prevented.
incoming flow at filling point
incoming flow above filling point
incoming flow below filling point
Screwdiameter
(mm)
Max.speed(r.p.m.)
Capacitymax
(m3/sec.)
30°
Homax.(mm)
Capacitymax
(m3/sec.)
Homax.(mm)
Capacitymax
(m3/sec.)
Homax.(mm)
35° 38°
300 118 0,016 2800 0,012 3200 0,011 3500
450 98 0,041 4000 0,033 4600 0,029 5000
600 75 0,082 4700 0,066 5400 0,059 5900
800 62 0,154 5500 0,125 6300 0,0112 6900
1000 53 0,272 6700 0,218 7700 0,196 8400
1250 46 0,430 7700 0,360 8900 0,312 9700
1500 40 0,690 8600 0,556 10000 0,500 10900
1800 36 1,080 9800 0,866 11400 0,777 12500
2100 32 1,500 9200 1,210 10500 1,087 11500
2450 29 2,210 8000 1,770 9100 1,591 10000
2800 26 2,980 10500 2,390 12100 2,150 13300
3200 24 4,070 10600 3,273 12100 2,940 13300
3600 22 5,360 11000 4,306 12600 3,860 13800
4050 21 7,060 11400 5,670 13000 5,090 14200
4500 19 9,000 11700 7,240 13300 6,500 14600
5000 18 11,530 12000 9,260 13600 8,320 14900
WIDE DESIGN RANGECAPACITY FROM 10 TO 11.500 L/SLIFT FROM 0 TO 25 M
Every single screw pump is specifically designed for each project. Because of that thereis always an optimum relationship betweenfunction and design. This can vary between acapacity of 10 and 11.500 l/s. As regards the lift,the possibilities are practically unlimited whenscrew pumps are installed in serial order. Theadjacent table shows an indicative overview ofthe most common options. Also screw pumpinstallations with different inclinations, whichwere quite often used in the past, can be quotedon request.
CHANGES IN THE CAPACITY ARE EASYAND, IF NECESSARY, STEPLESS
When the capacity of the screw pump must be adapted to very specific conditions, forwhatever reason, then this is normally easy to fixby using either a two-speed motor or a variablefrequency drive (VFD). In the case of fixed rpmone can consider, for longer and biggerdeviations, changing the pulleys of the V-belttransmission. In nearly all cases the pumpremains within its effective range.
Fillingpoint
Touch point
Pump efficiency
Pump capacity
Discharge and efficiencyat various inlet levelsbelow filling point
INSENSITIVE TO SUPPLY CONDITIONSAND, BECAUSE OF ITS LOW SPEED, NO PROBLEMS WITH CAVITATION
Because of the low revolutions and the nature of the screw pump no special demands have tobe met regarding the inlet channel of the screwpump. The screw pump is, contrary to othertypes, insensitive to supply conditions.Especially at higher revolutions critical supplyconditions could lead to cavitation, which inpractice fairly often occurs with competingpump types.
Screw pumps in serial order
DRIVE-UNIT OPTIONS
Depending on the local circumstances there is a choice of different drive-unit arrangements.Different options are shown schematically in the drawing below. Deviations from theseguidelines is, of course, possible, if so required.
TROUGHS
In choice of troughs there are several options.First of all there is the classic concrete trough,for which the screw pump itself is used to groutthe trough to its final shape, working at lowspeed and using a special mortar. When thisspecific know-how is not available it is possibleto order either a screw pump with a steel castingmould which is removed after the concrete hasbeen poured, in this way leaving the correctclearance between the screw pump and theconcrete, or with a cast-in steel (or stainlesssteel) trough, which will remain in the concrete.For special applications there is also the optionof a fully self-supporting steel trough or acompletely pre-fabricated screw pump, includingtrough bearings and drive-unit. The last optionhas the advantage that installation time isextremely short. For smaller screw pumps, a pre-fabricated pump can be installed as a tubescrew pump.
RESEARCH AND DEVELOPMENT
For many years Landustrie has been active inresearch to improve the screw pump evenfurther. The most recent results are the Eco-friendly lower bearing, which has been tested for over 10 years, amongst other locations at the Waste Water Treatment Plant of Zwanenburg(The Netherlands) as well as the use of the Finite Element Analysis on the Landustrie screw pump designs.
P � 30 kWP � 37 kW
P � 55 kWP � 45 kW
cast-in trough
concrete trough
tube screw pump
pre-fabricated screw pump
L A N D Y S C R E W P U M P S
LOWER BEARINGS
For the lower bearings Landustriehas four different standard types. The most recent is the Landy Eco-friendly lower bearing, with a numberof specific advantages (see theadjacent 3-D sketch).In the table we have compared thefour different Landustrie lowerbearings. All lower bearings, of anytype, only have to absorb radialforces. The lower bearing alsoabsorbs the length changes of thescrew pump due to differences intemperature.
Completely enclosed unit
No maintenance and no grease costs
3-dimensional self-aligning
Corrosion-freecast iron housing
Lower investment
No spare parts required
Exchangeable withexisting bearings
No grease pump andgrease lines required
Easier to install
Eco-friendly lubricated for lifetime of the bearing
High-performance seal
Eco-friendly Conventional Medium Heavy Duty
Lubrication Lifetime Grease Medium Grease
Grease filling ● ●
Grease return line NA On request NA ●
Maintenance required ●
3D-self-aligning ● ●
Water quality low low high low
Installation time low average low average
Heavy duty ●
Exchangeability with existing bearings ● ● ●
Investment low medium low high
Operational costs low medium low medium
Lifetime average average average long
LOWER BEARING SELECTION TABLE
ECO-FRIENDLY LOWER BEARING
wall-mounted bearing
CONDITION MONITORING
All existing and new screw pump installationscan be equipped with a condition monitoringsystem which on-line continuously suppliesdetails about both the upper and lowerbearings.This monitoring system is based on acousticemission sensors which detect possibleproblems at a very early stage. Not onlyoperating and maintenance costs will bereduced, but also the exploitation and usabilityof the installation will be increased.
UPPER BEARINGS
For the upper bearing Landustrie can offer thechoice between two different versions; awall-mounted or a foot-mounted upperbearing.The preference is normally for the wall-mounted upper bearing, firstly becausethe forces on the civil construction willbe better absorbed, and secondlybecause an odour-tight separation iscreated between the screw pump and theroom in which the drive-unit is installed. foot-mounted bearing
LANDY SCREW PUMPS BECAUSE...
Besides the general characteristics of the screwpump, the Landy screw pumps are distinguishedby:
In other words a first class product with
screw pump technology
Nearly 100 years experience
Efficient design - - Usually 2 flights- Limited deflection- Limited occuring tension- High efficiency
Ongoing R&D
Finite Element Analysis
Full in-house manufacturing
Totally reliable manufacturing schedulesand delivery times
Endplates- Fully watertight by means of caps
over threads of connection bolts- Fully parallel and centric manufacture
using special lathesReinforced leading edges of flights
Manufactured with permanent lifting eyesand balancing weights
Fully qualified welders- X-ray or ultrasonic- Welding Shop Approval
Coating. All required coatings areapplied professionally, and can besupplied with additional requirementsregarding sand, salt or pH.
Basic material of bearing shafts is nodularcast iron
Use of fully self-aligning bearings
World-wide service with local support
Superb after-sales service
Erection with competent and experienced Landustrie mechanics. Onrequest, we can also offer fullsupervision of installation.
STATE-OF-THE-ARTSTATE-OF-THE-ART
L A N D Y S C R E W P U M P S
01-2
007-
1500
EN
G.
Landustrie Sneek BVP.O. Box 199NL-8600 AD SneekThe Netherlands
Tel. +31 515 - 48 68 88Fax +31 515 - 41 23 98e-mail [email protected] www.landustrie.nl
Office address Pieter Zeemanstraat 6, Sneek
Watertechnology
REFERENCES
During the nearly 100 years of their existenceLandustrie has undertaken some 5000 screw pumpprojects, which are all unique in terms of designand execution, varying in power from 1 to 600 kWand in diameter from 10 cm to 5 meter, and inlength from 50 cm to 25 m. All these projects haveadded to the vast amount of knowledge andbackground information built up over the yearsregarding the design, manufacturing and installationof screw pumps. For every new project, you, as ourcustomer, are using this inexhaustible amount ofexperience.You will find some of our most recent projects inthe adjacent photo collage.
COVERS
On request Landustrie can cover the installationwith a modular light weight synthetic coverconstruction. Advantages are:
protection of the screw pump against thermalexpansioncreates a safe working environmentreduces the level of noise production
Hamburg, Germany
Zagreb, Croatia
Veneriete, The Netherlands (renovation)
Dublin, Ireland
Indianapolis, USA
Lynetten, Denmark
Cologne, Germany
Olifantsvlei, South Africa