EIJKELKAMP 0801 Manuale utente
M-0801E
Sandbox for pF-determination
Eijkelkamp Soil & Water
Nijverheidsstraat 30, 6987 EM
Giesbeek, the Netherlands
T +31 313 880 200
E info@eijkelkamp.com
I www.eijkelkamp.com © 2019-01
Meet the difference
User manual
2
Contents
On these operating instructions..........................................................................................................................................3
1. Introduction........................................................................................................................................................................3
2. Description of the sandbox............................................................................................................................................. 3
3. Technicalspecications...................................................................................................................................................4
4. Assembling the sandbox.................................................................................................................................................. 5
4.1 Before setting up the sandbox.................................................................................................................................5
4.2Setting up the sandbox.............................................................................................................................................. 7
5. Using the sandbox........................................................................................................................................................... 13
6. Tabletobelledinasmeasurementsaretaken...................................................................................................17
7. Troubleshooting...............................................................................................................................................................18
8. Maintenance of suction tables.....................................................................................................................................18
Appendix 1: General Information....................................................................................................................................... 19
Appendix 2: Description of different pF-sets................................................................................................................. 22
Appendix 3: Conversion factors ......................................................................................................................................... 23
Appendix 4: Soil sampling...................................................................................................................................................24
References and literature ...................................................................................................................................................25
Nothinginthispublicationmaybereproducedand/ormadepublicbymeansofprint,photocopy,microlmoranyothermeanswithout
previouswrittenpermissionfromEijkelkampSoil&Water.Technicaldatacanbeamendedwithoutpriornotication.
Eijkelkamp Soil & Water is not responsible for (personal) damage due to (improper) use of the product.
Eijkelkamp Soil & Water is interested in your reactions and remarks about its products and operating instructions.
3
On these operating instructions
If the text follows a mark (as shown on the left), this means that an important instruction follows.
If the text follows a mark (as shown on the left), this means that an important warning follows
relating to danger to the user or damage to the apparatus.The user is always responsible for its
own personal protection.
Italic indicated text indicates that the text concerned appears in writing on the display (or must be
typed).
1. Introduction
This Sandbox (acc. to ISO 11274) (art. no.: 0801) can be used to apply a range of pressures from pF 0 (saturation)
to pF 2.0 (-100 hPa). Sand is used to convey the suction from the drainage system to the soil samples. The
surfaceofthesandisexible,whichmakesiteasiertorestorethecontactbetweenit,andthesamples,after
they have been removed for weighing. This quality makes sand a better suction material than a stiff porous
plate, for this instrument.
IftheinuenceofhigherpF-valuesneedstobemeasured,thenadditionalequipmentisrequired.TheSand/
Kaolin box (art. no: 0802SA) can be used to determine moisture percentages at pF-values from 2.0 (-100 hPa)
to 2.7 (-500 hPa), while the pressure membrane apparatus (art. no.: 0803) can create pressures from pF 3.0
to pF 4.2. A pF-value of 4.2 is equal to -15,000 hPa of pressure, which is often taken as the lower limit of soil
moisture availability to plants.
Results of measurements taken with this sandbox correspond with points on the drying curves of the relevant
samples; associated with decreasing pressure. These pressure values are usually standard water potential
increments. The wetting curve, on the other hand, is determined by graphing the water content against
increasing pressure values. This curve is not identical to the drying curve, because the water content does
not respond instantaneously to changes in pressure (Hysteresis).
2. Description of the sandbox
The assembled sandbox can be seen in Figure 1. In the bottom of the box (1) is a PVC-pipe drainage system
(4).Thisboxislledwithnesyntheticsand,whichiscoveredwithanylonltercloth.Theassemblagestage
(Chapter 4) is only necessary prior to the initial use of the sandbox: After which, with proper maintenance
(Chapter9),thesandboxcanbeusedforseveralyears.Soilsamplecoreringsareplacedontopofthelter
cloth to take measurements.
If the sandbox has already been assembled then begin at Chapter 5.
The ‘Hanging Water Principle’ is used to apply suction to the soil samples. The difference in height between the
suction regulator (11) and the middle of the soil samples determines the amount of pressure. Pressure heads
(h)between0and-100cmcanbeapplied.Thesuctionregulator(11)isadjustedtoapplyspecicpressuresto
thesoilsamples.Thesamplesareweighedaftertheyhavereachedequilibriumataspecicpressure.Finally,
thesamplesaredriedandweighedtodeducethewatercontentateachspecicpressure.
Text
4
3. Technicalspecications
Item Specication
Soil sample rings (Ø 53mm) Max. 40
Dimensions of the box on its stand (excl. supply bottle etc.) 55.0 x 33.5 x 37.5 cm (l x w x h)
Operating range 0 hPa - 100 hPa
0 bar - 0.1 bar
pF 0 – pF 2.0
Reading accuracy 0.0001 bar
Fig. 1 : Assembled sandbox with numbered components
7
6
8
Tap B
Tap C
Tap A
14 43
10
12
11
9
13
5 1 2
Backside of sandbox
Tap D
1 Box
2 Box frame
3 Box lid
4 Drainage pipe
5 Supply pipe
6 Supply bottle
7 Bottle lid
8 Bottle stand
9 Discharge pipe
10 Sliding measuring stand
11 Suction regulator
12 Evaporation reservoir
13 Outowpipe
14 Sample
1 metre
5
4. Assembling the sandbox
If the sandbox is already assembled then skip to Chapter 5.
All of the tubes are connected and tested for leakage before delivery.
Take care not to break the tube connections while unpacking.
Construct the sandbox using the following instructions (numbers refer to Figure 1).
4.1 Before setting up the sandbox
Beforethesandboxisassembled,theplasticdrainagepipe(4)insidethebox(1)mustbecoveredwithlter
cloth.Thesuppliedlterclothhastwolayers,andis6cmwide.Theplasticdrainagepipeneedstobecovered
by 3 layers of cloth to disperse the suction, and to stop sand from blocking the pipe’s holes when this suction
is applied.
Toapplythelterclothtothepipe,thefollowingstepsshouldbefollowed:
1. Cuta3.5mlongsectionfromthesuppliedrollofltercloth.
2. Cutdownonesidethelterclothtomakeasingle12cm
wide layer (Fig. 2).
3. To knot the cloth to the pipe, a 10 cm long section is cut into
the end of the strip to form two ties (Fig. 3)
Fig. 2 Cut 3.5 m down one side
Fig. 3 The 10 cm long ‘ties’
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4. Saturatethelterclothindemineralisedwater(Fig.4).
5. Tiethelterclothtooneendofthedrainagepipe-where
it enters the inside of the box.
6. Coilthelterclotharoundthedrainagepipesothateach
consecutive winding covers two thirds of the width of the
previous one. This will ensure that the entire pipe is covered
bythreelayersofltercloth(Fig.5).
7. Fasten the cloth at the other end of the pipe.
8. Cut off the extra cloth, and tie the end to one end of the
drainage pipe (Fig. 6).
Fig. 4 Saturate the lter cloth
< 12 cm >
4 cm
< >
Three
layers
cloth
Drainage pipe surface
Fig. 5 Filter cloth winding
Fig. 6 Complete cloth covering
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4.2 Setting up the sandbox
1. Select a completely level, vibration free table that is at least
1.0 m high.
Vibration may cause a leak between the sidewalls of
the box and the sand.
2. Place the sandbox on this table, with tap A facing the front
and turned to the ‘Closed’ position (Fig. 7).
3. Fix the sliding measuring stand (10) with suction regulator
(11) and evaporation reservoir (12) to the box (1), using the
two bolts provided (Fig. 8).
4. Allowtheoutowpipe(13)fromthesuctionregulator(11)
to hang from the table into a bucket (Fig. 9).
5. Boil8litreofdeminineralizedwater,andllthesupply
bottle (6) with it once it has been left to cool (you may add
Copper Sulphate to reduce algae/bacterial activity).
6. Place the supply bottle (6) on its stand (8) to the left of the
box. The stand elevates the base of the bottle to the same
height as the base of the box (1).
Fig. 7 Tap A 'Closed'
Fig. 8 Fix sliding measuring stand
Fig. 9 Outow from suction regulator
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7. Connect the supply bottle (6) to tap A with the supply pipe
from the back of the box. Leave tap A ‘Closed’ (Fig. 10).
You may add (0.01 mg/l) copper sulphate to reduce
microbiological activity
The water level in the supply bottle should not be
higher than the top of the box, because it may cause
thewatertoowtooquickly(7500ml).
8. Air bubbles should now be removed from the piping in the
system. Begin by opening the lid of the supply bottle (6),
and turning the supply tap B 'On' (Fig. 11).
9. Turn tap A, on the front of the box, to ‘Supply’, and allow
watertoowfromthesupplybottle(6)intothebox(1)until
the box is half-full with water (Fig. 12).
10. Turn tap A to the ‘Closed’position.
Fig. 10 Supply bottle attached to tap A
Fig. 11 Turn tap B 'On'
Fig. 12 Half-ll box with water
The water level in the supply bottle (1) should never fall below the plastic drainage pipe inside the
box (4500 ml). Turn tap A to ‘Closed’whenrellingthesupplybottle.Letthewatersettleinthe
supply bottle before returning tap A to ‘Supply’.Tapgentlyonthetubesaswaterisowingtohelp
bubbles escape.
Tap B
Tap A (back)
To supply
bottle
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11. Open tap D, at the back of the box (green) and allow some
watertoowfromthebox(1)intoabeaker(Fig.13).
The water level in the box (1) should never fall below
the plastic drainage pipe.
12. When there are no bubbles left between tap B and tap D,
close tap D while leaving tap B open.
13. Turn tap A to the ‘Closed’ position. There should now be no
bubbles between tap B and tap A, and between tap A and
the drainage pipe.
14. Fill the regulator bottle of the evaporation reservoir (12)
with demineralised water, and put the plug back in before
replacing the bottle (Fig. 14).
15. Set the suction regulator (11) to its lowest position (max.
suction) near the bucket. (Fig. 15).
16. Turn tap A to ‘Discharge’,andallowwatertoowfromthe
box (1) through the suction regulator (11) into a bucket
until there are no bubbles between tap A and the suction
regulator (Fig. 15).
In general: if you place the tap in the discharge position,
theremustbeawaterowfromthesandboxtowardsthe
suction regulator (this is the position for measurements).
Ifthetapisplacedinthesupplypositionthereisawaterow
from the supply bottle towards the sandbox. Important is
to have the water level in the supply bottle always higher
than the sand level in the box.
Fig. 13 Air bubbles released through tap D
Fig. 14 Evaporation reservoir
Tap D
Fig. 15 Suction regulator at maximum
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17. Turn tap A to the ‘Closed’ position.
18.Leave tap B on so that water runs out of tap C when you
openit.LetsomewateroutoftapCtoremovethenalair
bubbles (Fig. 16).
There must be no air-bubbles in the system from this
point onwards.
19. Saturate some synthetic sand with running demineralised
waterandstirrmlytoremoveair(Fig.17).Thereshould
be a high ratio of water to sand (Fig. 18) so that it can be
easily poured into the box (1). For the textural composition
of the sand see Table 1.
Table 1: Textural composition of synthetic sand
Particlediameter(mμ) Percentage occurence
106 0
75 6.3
63 61.4
53 22.1
45 4.4
<45 5.8
20.Slowly pour the water-saturated sand into the water in
the sandbox (Fig. 19) while the water is constantly stirred
to expel any entrapped air. Alternatively, the sand may be
added with a ladle.
Be careful to avoid damaging the drain system while
stirring.
Fig. 16 Let some water out of tap C
Fig. 17 Saturate sand with water
Fig. 18 A high ratio of water to sand
Fig. 19 Adding water-saturated sand
Tap C
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