1.6. Water-intake constructions for receiving of the water from underground sources.

For in taking of underground water are used different constructions – mining hole, pit wells, horizontal and ray water-intakes, capitation cameras.

Pit wells are used usually for extraction of ground without pressure or interstate water of the upper horizons. Usually depth of pit wells doesn’t exceed 10 meters but in separate cases can reach 30m. Isolated wells are used predominantly for local systems of water-supply, so get the biggest wide spreading in the village locality. For centralized water supply used groups of pit wells. Connected by plumbing’s with gathering well for in taking of water from it by pumps.

Pit well is vertical pit of rectangular or round cross-section with diameter of 1-1,5 m (dr.1.11). Water receiving part of the well is deepens into the water-bearing layer not less than for 2 m. Bottom is covered by sand-gravel filter. Water-receiver of the pit is taken out over the earth surface on 0,8 meter, covered by lid or hatch and equipped by ventilation. Around the well installed pavement and clay castle (lock). Shaft of the pit is made from timber, stone, brick, concrete and reinforced concrete. The most perfect are wells made from reinforced circles.

Drawing 1.11. Scheme of pit well

1 – windows from porous concrete for water filtration; 2 – shaft; 3 – receiver; 4-lid; 5- ventilation tube; 6-pavement; 7 – channel for water drainage; 8 – claim castle (lock); 9 – pressure plumbing; 10 – pumping aggregate; 11 – receiving vent; 12 – inverse filter; 13 – bottom of the water bearing layer.

For water intake from the well are used erlifts, piston and centrifugal pumps. Calculation of pit wells consists in determination of its diameter and number taking into account data expenses, in the checking capacity of the well and allowable depth of water level decreasing.

Water intake bores (tube wells) are used in cases when underground waters lies on the depth less than10 meters, and power of interstate layer doesn’t exceed 5m. Bore consists of 3 main elements (receiver, shaft and water-receiving part. Receiver is intended for fixing of mouth of bore, and also location of armature and equipment. Height of receiver should be not less than 2,5 m.

Shaft of the bore is fixed by tubes for protection of walls from falling in powdery rocks. Water receiving part of the bore is equipped by filter, which should not pass particles of water-bearing rocks. There are used different types of filters: tubular with round and chapy apertures; net, in which filter net is located on the framework; gravel, in which coarse-gained sand or gravel is located between water-bearing ground and basic framework.

Choosing the place for bore location it is necessary to take into consideration that during water pumping out on some distance around the well takes place falling of static level. In the same time immediately near the well level decreasing is the maximal, and with removing it decreases, reaching on some distance mark of static level. Decreasing of static level around the well in the transversal cross-section is represents as curve line, which is called as depression curve ( dr. 1.13). Line from the well axis to the point of touch of depression curve to the line of static level is called radius of depression or radius of well influence. Area around the well which is bordered by depression curve is called depression funnel.

Drawing 1.12. Scheme of water intake bore

1 – soil strewing for receiver warming; 2 – hatch; 3 – plunger with oven door; 4-manometer; 5-bitumus isolation; 6 – stairs; 7 – bottom of receiver; 8 – mouth of neck; 9 – electric cable; 10 – electric engine; 11 – crocus (корок); 12 – settler; 13 – working surface of the filter; 14 – above-filter pipe; 15 – epsilon; 16 - lock for filter drawing to the bore; 17 – net filter; 18 – pump; 19 – water-lifting pipe; 20 – exploitation column; 21 – crushed rock preparation; 22 – oven door; 23 – inverse vent; 24 – plumbing with screen for throwing away of washed water; 25 – ventilation pipe; 26 – difmanometer; 27 – pressure plumbing; 28 – water-bearing layer roofing; 29 – water bearing layer;30 – water-bearing layer bottom.

Drawing 1.13. Depression curve

1 – static level of underground water; 2 – depression curve.

Radius of the depression curve depends on character of water-bearing rock. If we know coefficient filtration rock it is possible to determine influence radius of the well and correspondingly borders of depression funnel. If on the area of depression funnel of one well locate another well they will influence to each other and total expenses of water from such wells will be less. Thus, well should be located one from another on the distance not less than double radius of depression curve.

Calculation of parameters of water intake constructions should be made according to calculation formulas which are in special literature.

Horizontal water-intakes (dr. 1.14) are constructed when the power of the underground water is small (up to 10 m/s) and deep bending of water bearing level up to 8 m, mainly near surface water channels and basins and also when it is necessary to intercept infiltration underground current on as widest width as possible. Such water intakes are lied in borders of water bearing layer perpendicularly to the direction of underground current upper than settlement, industrial enterprises, animal farms etc. Controlling wells are intended for water-intake ventilation and its overlook.

Drawing 1.14. Scheme of the horizontal water-intake:

1 – drainage tube; 2 – controlling well; 3 – water-intake well.

Ray water-intakes (dr.1.15) is variety of pit wells and consists on water-intake well and water-receiving rays (drens). Quite often they are used for selection of underground waters near the rivers. For water selection of under-channel current are used also water-intakes of filtration type (dr.1.16). These water-intakes has analogical construction as other pit wells and they are located along the river.

In places where underground water comes on the surface there are appeared springs. Gathering of such water is realized through capitation cameras – water intake buildings of different constructions. Most often are used reinforced-concrete gathering cameras into which water comes through bottom or walls (dr.1.17). Capitation cameras are intended for opening and equipping of spring escape, protection from surface polluting and providing of water coming into gathering camera. It is practically to install them only in cases of absence of more reliable sources of water-supply, with enough capacity, possibility of sanitary protection from pollution or for special usage (f.e. as source of healing mineral water).

Drawing 1.15.

Ray water –intake

1 – reinforced concrete pit well; 2 – drains; 3 – filtering part of drains;

4 – above ground pavilion; 5 – water-bearing soil.

Drawing 1.16. Water –intake of infiltration type

Drawing 1.17. Capitation camera for water receiving from outgoing source

1.7.Pumps and pumping stations

1.7.1 Pump types

Pumps are hydraulic machines which trans miss to water, which flows inside of them, energy, got from outside. Due to it fluid lifts on some height or got corresponding pressure. Chiefly to pumps connected mechanical energy (centrifugal, piston etc ) or, rarely are used potential or kinetic energy of liquid or gaseous medium (ray, erlifts, etc).

On work and construction principle of working organs pumps are subdivided into volume and dynamic. In dynamical liquid under the action of force moves in the camera and which is constantly connected with entrance and escape of the pump. Volumetric pumps works on principle on which fluid moves by the way of periodic camera volume change during variable connection with its escape and entrance. Fluid on each circle is given by certain pistons – volumes.

To dynamical pumps belong: vane (centrifugal, axial, diagonal), in which fluid moves by the way of flowing around vanes of working circle (dr.1.18a,b); vertical, in which fluid moves on periphery of the working circle (dr. 1.18 c); screw, in which fluid moves by screw along its axis (dr.1.18d); erlifts (air water lifts), in the work base of which lies principle of using of difference of density of water and air-water mixture in the system of connected plumbing’s (dr.1.19); stream, which used energy of fluid, which is given from outside (dr.1.20); hydraulic ram, in which for lifting of fluid is used energy of hydraulic knock, and other.

Drawing 1.18. Schemes of centrifugal (a,b) from vortical( c) and screw (d)

pumps:

1 – working circle; 2- curvilinear vane; 3- body; 4,5 - absorption and pressure plumbing; 6 - screw

Volumetric or piston pumps work on the principle of enforced mechanical displacement of locked volume of fluid (dr.1.21).

Drawing 1.19. Scheme of airlift working:

a -forced; b- absorbing; 1 – water lifting tube; 2 – air pipe from compressor;

3 – casing pipe; 4 –sprayer; 5-emulsion; 6 – pipe to vacuum pump.

Drawing 1.20. Water-stream pump:

a - pump scheme; b – scheme of pump installation; 1- absorbing pipe;

2-pressure pipe; 3-nozzle; 4-mixing camera; 5-diffuzer; 6 – neck.

Plumbing pumping stations are equipped usually by centrifugal pumps, which have advantage before pumps of other types: simple by construction, reliably by exploitation, provide uniform water supply and can immediately connected with electric engine. Centrifugal pumps are subdivided by the following characteristics: pressure – low pressure up to 0,2 MPa, middle pressure 0,2-0,6 MPa and high pressure more than 0,6 MPa; on number of working circles – single-circle and multi-circle; on shaft location – horizontal or vertical; in dependence on nomination – plumbing, sewerage, acidic etc; on water absorption – one and two-sided entrance; on construction conditions – underground, floating, deeper, artesian etc. Coefficient of useful work of these pumps is quite high – 0,6-0,8.

Drawing 1.21. Schemes of piston pumps:

a – vertical; b – horizontal; 1 – absorbing pipe; 2 – absorbing valve; 3 – working camera; 4 – pressure valve; 5 – pressure pipe; 6 – piston; 7 – cylinder; 8 – rod; 9 – slider; 10 – connecting rod; 11 – crank.

Piston and vertical pumps for water lifting are used now rarely and only in cases when on small expenses is necessary high pressure. Piston pumps are slow, have significant clearances and weight, but it is possible to start without water filling; coefficient of useful action is between 0,7-0,9.