ES2382973A1 - Infiltrometer of disc and method of measurement of the infiltration rate in a soil using such infiltrometer (Machine-translation by Google Translate, not legally binding) - Google Patents

Abstract

Infiltrometer of disc and procedure of measurement of the infiltration rate in a floor using said infiltrometer. It comprises a base (1) resting on the ground; a reservoir (6) of water, a tube of mariotte (4) that passes through the base (1), allowing the flow of water towards the ground; a bubble tower (3) connected to the pipe of mariotte (4) and that provides the air that allows the flow of water to the ground; and a valve (10) that allows the passage of water from the tank (6) to the pipe of mariotte (4). A first connecting pipe (9) transports air from the pipe of mariotte (4) to the tank. A pressure sensor (11) measures the water height of the mariotte tube (4) (valve (10) open) with water flow to the ground ht and without flow hto the procedure comprises a) determining hto, and ht, and b) calculating the value of said infiltration rate q from hto, and ht. (Machine-translation by Google Translate, not legally binding)

Description

OBJECT OF THE INVENTION

The present invention can be included within the technical field of soil characterization from the measurement of its hydraulic characteristics, such as sorptivity and hydraulic conductivity.

Specifically, the object of the invention relates to a highly autonomous disk infiltrometer capable of directly measuring infiltration rate values, being able to adapt to perform several simultaneous measurements at different points and alternatively to perform long-term measurements at one point. and whose measurement is independent of the relative position between the reservoir and the mariotte tube of the infiltrometer. A second object of the invention concerns a method of measuring the infiltration rate in a soil using the aforementioned infiltrometer.

BACKGROUND OF THE INVENTION

The disk infiltrometer is a technique that, due to its great maneuverability and speed in in situ measurements of infiltration, is widely used to measure, in conditions close to saturation, hydraulic conductivity (K), sorptivity (S) or number and size of macro and mesoporos conductors of water in the ground.

This instrument, usually made of methacrylate, consists of a base or disk on which a water tank and a bubbling tower are inserted. The water reservoirs used in the infiltrometers are usually cylindrical tubes of reduced diameter (eg 5 cm. Of internal diameter, (di) that allow for fairly precise measurements of water level drops. The measure of cumulative water infiltration on the ground, from which the hydraulic properties are calculated, it is generally done manually by noting, at constant intervals of time, the decrease of the water level in the infiltrometer reservoir.This simple measurement method, which requires a Continuous attention on the infiltrometer can be easily automated using a pressure transducer inserted into the base of the infiltrometer reservoir and connected to a datalogger or using the TDR technique by inserting a three electrode probe into the infiltrometer reservoir.

This type of design obliges, however, that in long-term measurements (eg infiltrations at several tensions at the same point) the measures to fill the tank must be interrupted, a task that, apart from tedious, can cause errors in infiltration measures due to the infiltrometer's own handling. On the other hand, these designs only allow the use of a single water tank per disk.

The classic infiltrometer design, whose water tank rests on the disk has evolved into new prototypes in which the tank has become independent from the base. These new designs allow to reduce the weight on the sampling surface and thus eliminate possible errors related to the collapse of the soil structure in conditions close to saturation, especially in freshly carved soil.

The drawbacks of this type of disk infiltrometers known to date are described below:

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They do not allow simultaneous monitoring of several infiltration points using a single water tank.

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They force interruption of the measurement procedure to refill the water tank when long-term infiltration measures are carried out.

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 They perform direct measures of cumulative infiltration and not infiltration rates.

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They do not allow to estimate the rate of instantaneous infiltration of water in the soil.

DESCRIPTION OF THE INVENTION

It is an object of the present invention to provide a disk infiltrometer that solves the aforementioned drawbacks.

A second object of the present invention is a method of measuring the infiltration rate in soils using the aforementioned infiltrometer.

The disk infiltrometer of the invention comprises a base, a water reservoir, a mariot tube and a bubbling tower. The mentioned elements do not need to be joined in the same compact block but can be conveniently separated and connected to each other in an appropriate manner.

The base has a substantially flat support face adapted to rest on a floor whose hydraulic characteristics are to be determined. The bubble tower is connected to the lower part of the mariot tube, at the base of the disk, by means of a first bubble tube, while said bubble tower is open to the atmosphere through a second bubble tube whose Position is adjustable. The bubble tower provides, by corresponding regulation of the position of the second bubble tube, the suction necessary to allow water from the mariotte tube to seep into the ground at negative voltage. The base incorporates the mariotte tube inserted whose lower face is open to the atmosphere through the support face of the base. This arrangement allows, once the mariot tube is partially filled with water (as will be explained later), said water is filtered inside a substantially flat area of soil on which the support face of base.

The mariot tube is adapted to allow the reading of the water column height that it presents or, equivalently, the pressure associated with said height, either by means of a graduated scale, or, alternatively or additionally, by means of a sensor of pressure incorporated in the mariotte tube that determines the water pressure inside the mariotte tube and which is adapted to calculate the water column height equivalent to said pressure.

The water tank contains the water that is used for the hydraulic characterization of the soil. Said water tank is doubly connected to the mariot tube:

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 a first connection tube, arranged at a first height, communicates the bottom of the water tank with the mariotte tube. Water flows from inside the first connection tube from the water tank to the mariot tube.

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the upper part of the mariot tube is closed to the atmosphere by means of closing means, through which a second connecting tube is inserted, the first end of which is inside the mariot tube. The second free end of the second connecting tube is connected to the tank at a second height, greater than the first height. Inside the second connection tube, air circulates from the mariot tube to the water tank.

Preferably, the first tube and the second tube are silicone.

A valve allows to regulate the circulation of water between the water tank and the mariot tube.

The procedure for determining the infiltration rate of the invention using the described infiltrometer begins with the determination of the height of water column HT0 inside the mariot tube in the absence of water filtration into the soil. To do this, with the valve closed to prevent the circulation of water between the water tank and the mariot tube, the base is placed on the ground, interposing between the base and the ground some impermeable means that prevent water seepage from the mariotte tube towards the ground. The valve is then opened, whereby the mariot tube is partially filled with water until a pressure equilibrium occurs between the mariot tube and the water tank. When said pressure equilibrium occurs, the equivalent HT0 height of the water column within the mariot tube is determined by the pressure sensor or by visual registration on the graduated scale.

Then, the impermeable media is removed, and the infiltrometer base is placed again on the ground, which allows water filtration from the mariot tube to the ground. As a result of the loss of load due to the flow of water from the mariotte tube to the ground, a decrease in the level of water within the mariotte tube occurs. The pressure sensor (or, alternatively, a visual register on the graduated scale) continuously determines said water pressure or height and allows, where appropriate, to calculate the value of the HT height of the equivalent water column, for each instant of measurement .

From the values of HT0 and HT calculate the difference LHT = HT0 - HT. The unknown infiltration rate Q [m3 s-1] is determined by the following expression:

Q = (Q1 + Q2) / Q3, where

Q1 = (128 and L) / (� g D4)

Q3 = 16 (K1 + K2 + ... + Kn) / (g D4 �2)

Q2 = [(Q1) 2 + 2 * Q3 LHT] 1/2

where D and L [m] are the internal diameter and length (respectively) of the first tube, g [m s-2] is the acceleration of gravity, and [m2 s-1] is the kinematic viscosity of water, LHT [m] is, as indicated above, the loss of load in the connection pipe between tank and mariot tube expressed in equivalent water column heights, and Ki (i = 1, 2, ..., n) These are the singular load loss constants associated with each of the n existing constraints in the hydraulic circuit.

The invention allows to implement recording and calculation means that record HT (at defined time intervals) from the measurements of the pressure sensor and that subsequently calculate LHT for each moment and, consequently, the series of instantaneous values of Q, which can be, in turn, stored and processed (monitoring, graphics, etc.) through appropriate storage media and processing means.

The advantages of the infiltrometer and the method of measuring the infiltration rate described in the present invention with respect to the known infiltrometers and the measurement method used above are set forth below:

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 The water tank can be adapted to be connected to various mariot tubes, which allows the determination of the infiltration rate at different points simultaneously using a single water tank.

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The water tank can be arbitrarily large, which allows the execution of long-term measures.

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It provides direct and instantaneous measurements of the infiltration rate, and not just accumulated measures.

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It determines infiltration rate measures free of the error associated with the loss of load in the first tube.

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The size of the tank and the dimensions of the first tube are easily adaptable to the realization of measurements for a wide range of infiltration rates.

DESCRIPTION OF THE DRAWINGS

To complement the description that is being made and in order to help a better understanding of the characteristics of the invention, according to a preferred example of practical implementation thereof, a set of drawings is attached as an integral part of said description. where, for illustrative and non-limiting purposes, the following has been represented:

Figure 1.- Shows a view of the disk infiltrometer according to the invention.

PREFERRED EMBODIMENT OF THE INVENTION

The infiltrometer of the invention comprises a 10 cm cylindrical base (1). in diameter that incorporates in its lower part a substantially flat support face (2), adapted to rest on the floor to be characterized. The base (1) is connected to a bubbling tower (3) that provides the necessary air to allow water to seep into the ground. On the base (1) a mariot tube (4) of 35 cm is inserted. height and 2.5 cm. Inner diameter The mariot tube (4) is opened by a lower base (5), through the support face (2). The mariot tube (4) incorporates a pressure sensor (11) that determines the water pressure inside the mariot tube (4) and that is adapted to calculate the water column height equivalent to said pressure.

The infiltrometer also incorporates a reservoir (6) of water that is doubly connected to the mariot tube (4):

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 a first silicone connection tube (9), arranged at a first height, communicates the bottom of the water tank (6) with the mariot tube (4). Water flows from the first connection tube (9) from the water tank (6) to the mariot tube (4), and

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 A second silicone connection tube (7) is adapted to allow air to pass from the mariot tube (4) to the water tank (6). The mariot tube (4) has a plug (8) with a hole, allowing the hole to insert a first end of the second connecting tube (7) into the mariot tube (4). The second free end or end of the second connection tube (7) is inserted into the water tank (6) at a second height, greater than the first height.

A valve (10) allows to open or close the water circulation between the water tank (6) and the mariot tube (4).

The method comprises a first step of determining the height of water column HT0 inside the mariot tube (4) in the absence of water filtration to the ground. To do this, with the valve (10) closed to prevent water circulation between the water tank (6) and the mariot tube (4), the base (1) is placed on the ground, interposing between the base (1 ) and the ground waterproof means, such as plastics, which prevent water seepage from the mariotte tube (4) to the ground. Next, the valve (10) is opened, whereby the mariot tube (4) is partially filled with water until a pressure equilibrium occurs between the mariot tube (4) and the reservoir

(6) of water. When said pressure equilibrium occurs, the equivalent HT0 height of the water column inside the mariot tube (4) is determined by the pressure sensor (11).

In a second stage, the impermeable media is removed, and the base of the infiltrometer is placed again on the ground, which allows the filtration of water from the mariotte tube (4) to the ground. As a result of the flow of water from the water tank to the ground through the mariotte tube (4), a decrease in the level of water inside the mariotte tube (4) occurs. The pressure sensor (11) continuously determines said pressure and calculates the value of the HT height of the equivalent water column, for each instant of measurement.

The unknown infiltration rate Q [m3 s-1] is determined by the following expression, based on the difference LHT = HT0 - HT:

Q = (Q1 + Q2) / Q3, where

Q1 = (128 and L) / (g D4)

Q3 = 16 (K1 + K2 + ... + Kn) / (g D4 2)

Q2 = [(Q1) 2 + 2 * Q3 LHT] 1/2

where D and L [m] are the internal diameter and length (respectively) of the first tube, g [m s-2] is the acceleration of gravity, and [m2 s-1] is the kinematic viscosity of water, LHT [m] is, as indicated above, the loss of load due to the flow of water through the reservoir connection tube and mariot tube expressed in equivalent water column heights, and Ki (i = 1, 2,. .., n) are the singular load loss constants associated with each of the n existing constraints in the hydraulic circuit.

The invention allows to implement recording and calculation means that record HT (at defined time intervals) from the measurements of the pressure sensor and that subsequently calculate LHT for each moment and, consequently, the series of instantaneous values of Q, which can be, in turn, stored and processed (monitoring, graphics, etc.) through appropriate storage media and processing means.

Claims (9)

 R E I V I N D I C A C I O N E S  1.- Disc infiltrometer characterized in that it comprises:

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a base (1), which incorporates a substantially flat support face (2) adapted to rest on a floor whose hydraulic characteristics are to be determined;

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a water tank (6) containing the water used for the hydraulic characterization of the soil;

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a mariotte tube (4), inserted in the base (1), with the lower base of the mariotte tube (4) open through the support face (2) of the base (1), allowing water filtration of the water tank (6) to the ground through said lower base,

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a valve (10) adapted to allow and interrupt the passage of water from the water tank (6) to the mariot tube (4), and

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a bubbling tower (3), connected to the lower part of the mariot tube (4), adapted to provide the necessary air suction to allow filtering of the mariotte tube water (4) to the ground, where the tank ( 6) Water is doubly connected to the mariot tube (4) by means of:

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a first connection tube (9), arranged at a first height, which connects the lower part of the water tank (6) with the mariot tube (4), where water circulates inside the first connection tube (9) from the water tank (6) to the mariot tube (4), and

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a second connecting tube (7), inserted in closing means (8) located in the upper part of the mariot tube (4), said upper part being closed to the atmosphere by said closing means (8), the first end of the second connection tube (7) inside the mariot tube (4), as well as the second free end of the second connection tube (7) is connected to the water tank (6) at a second height, greater than the first height, and inside the second tube

connection (7) air circulates from the mariot tube (4) to the tank (6) of water, where the mariotte tube (4) is adapted to allow the reading of the column height in said mariot tube (4) or, equivalently, the pressure associated with said height. 2.-Disc infiltrometer according to claim 1, characterized in that the mariot tube (4) incorporates a graduated scale adapted to allow the reading of the water column height in the mariot tube (4). 3.-Disc infiltrometer according to claim 1, characterized in that the mariot tube (4) incorporates a pressure sensor (11) which determines the water pressure inside the mariot tube (4) and which is adapted to calculate the water column height equivalent to said pressure. 4.-Disc infiltrometer according to any one of claims 1 to 3, characterized in that it incorporates recording and calculation means, adapted to record the value of the water height in the mariotte tube (4) HT at intervals of time defined from the measurements of the pressure sensor (11) and to calculate the difference between HT and the value of said height under conditions of non-filtration of HTO water. 5. Disk Infiltrometer according to claim 4, characterized in that it incorporates storage and processing means adapted to store and process a series of instantaneous HT values taken by the pressure sensor (11) and perform rate calculations of infiltration Q. 6. Procedure for measuring the infiltration rate in a soil using the disk infiltrometer described in claims 1 to 5, characterized in that it comprises the steps of:

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HTO water column height determination in the tube

5 mariotte with the valve (10) open, in conditions of no water flow to the ground;

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Determination of the water column height HT in the mariot tube with the valve (10) open in conditions of water flow to the ground:

10 - determination of the infiltration rate Q from HTO, and HT. 7. Method for measuring the infiltration rate in a soil according to claim 6, characterized in that the determination of HTO comprises the steps of: 15 - dispose of impermeable means between the floor and the base (1), which prevent the flow of water between the mariot tube (4) and the floor;

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open the valve (10), allowing the passage of water between the tank

(6) water and mariotte tube (4), and

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record the HTO reading of the water column of the mariot tube 20 (4);

SPANISH OFFICE OF THE PATENTS AND BRAND Application no .: 200930735 SPAIN Date of submission of the application: 25.09.2009 Priority Date: REPORT ON THE STATE OF THE TECHNIQUE 51 Int. Cl.: G01N15 / 08 (2006.01) G01N33 / 24 (2006.01) RELEVANT DOCUMENTS

Category

56 Documents cited Claims Affected

TO

F.X.M. CASEY and N.E. DERBY. "Improved design for an automated tension infiltometer". SOIL SCI. SOC A.M. J., VOL. 66. JANUARY-FEBRUARY 2002. 1-7

TO

US 4884436 A (ANKENY MARK D ET AL.) 12/05/1989, column 2, line 43-column 6, line 21; Figure 1; claims 1,12 and 13. 1-7

TO

DE 4311032 A1 (PUNZEL JUERGEN DIPL PHYS DR RE) 10/21/1993, Summary of the EPODOC and WPI database; figures. Recovered from EPOQUE 1-7

TO

DE 4041960 A1 (FORSCHZENT BODENFRUCHTBARKEIT) 02/07/1992, Summary of the EPODOC and WPI database; Figures 1-6. Recovered from EPOQUE. 1-7

Category of the documents cited X: of particular relevance Y: of particular relevance combined with other / s of the same category A: reflects the state of the art O: refers to unwritten disclosure P: published between the priority date and the date of priority submission of the application E: previous document, but published after the date of submission of the application

This report has been prepared • for all claims • for claims no:

Date of realization of the report 01.06.2012

Examiner B. Weaver Miralles Page 1/4

REPORT OF THE STATE OF THE TECHNIQUE Application number: 200930735 Minimum documentation sought (classification system followed by classification symbols) G01N Electronic databases consulted during the search (name of the database and, if possible, terms of search used) INVENES, EPODOC, WPI, NPL, INTERNET State of the Art Report Page 2/4  WRITTEN OPINION Application number: 200930735 Date of Written Opinion: 01.06.2012 Statement

Novelty (Art. 6.1 LP 11/1986)

Claims Claims 1-7 IF NOT

Inventive activity (Art. 8.1 LP11 / 1986)

Claims Claims 1-7 IF NOT

The application is considered to comply with the industrial application requirement. This requirement was evaluated during the formal and technical examination phase of the application (Article 31.2 Law 11/1986).  Opinion Base.- This opinion has been made on the basis of the patent application as published. State of the Art Report Page 3/4  WRITTEN OPINION Application number: 200930735 1. Documents considered.- The documents belonging to the state of the art taken into consideration for the realization of this opinion are listed below.

Document

Publication or Identification Number publication date

D01

F.X.M. CASEY and N.E. DERBY. 01.01.2002

D02

US 4884436 A (ANKENY MARK D et al.) 05.12.1989

D03

DE 4311032 A1 (PUNZEL JUERGEN DIPL PHYS DR RE) 21.10.1993

D04

OF 4041960 A1 (FORSCHZENT BODENFRUCHTBARKEIT) 02.07.1992

2. Statement motivated according to articles 29.6 and 29.7 of the Regulations for the execution of Law 11/1986, of March 20, on Patents on novelty and inventive activity; quotes and explanations in support of this statement Claim 1: Document D01 is considered as the closest state of the art. Said document discloses a disk infiltrometer consisting of a base, a water tank and a bubbling tower connected by a tube. It differs from the first claim in that it does not have an intermediate mariot tube between the bubble tower and the water tank and inserted on the base that rests on the ground, nor the valve to allow the passage of water from the tank to the tube from mariotte. The technical effect is that the mariot tube is partially filled with water and then filtered to a flat area of the ground on which the base of the disc is supported. The technical problem posed is how to measure the infiltration rate from the water losses that occur along the silicone tube that connects the water tank with the disk through the mariotte tube. However, in none of the aforementioned documents, which reflect the state of the prior art closest to the object of the request, have all the technical characteristics defined in claim 1 of the application been found. Likewise, it is considered that the differential characteristics do not seem to derive in an evident way from any of the cited documents, either individually or through a combination between them. For all of the above, it is concluded that claim 1, and consequently, all its dependents (claims 2-5), would satisfy the requirements of novelty and inventive activity according to articles 6.1 and  8.1 of patent law 11/1986. Claim 6: Document D01 is considered as prior art. Said document discloses a disk infiltrometer consisting of a base, a water reservoir, a bubbling tower. As it differs from the claimed infiltrometer in that it does not have an intermediate Mariotte tube between the bubble tower and the water tank, inserted on the base that rests on the ground, it is not possible to determine the water column in said tube. Therefore, said claim and its dependent (claim 7) have novelty and inventive activity according to articles 6.1 and 8.1 of patent law 11/1986. Other documents: Document D02 discloses an automated tension infiltrometer consisting of a bubble tower connected to a mariot tube located on a disk that in turn rests on the ground. Said mariot tube inserted in the disc, has the lower base open allowing the filtration of water not from the tank but from the bubble tower, filtering water to the area of the ground where the base is supported to know the volume of water column in front to the expected accumulated infiltration. Document D03 describes a double ring infiltrometer for determining the hydraulic conductivity of the soil consisting of an infiltration system connected to a water supply through a mariot tube that is divided into two concentric filtration chambers and separated from each other. Document D04 discloses a form of in situ measurement of the infiltration characteristics of the soil, measuring the infiltration rate as a temporary dependence, by means of a sensor mounted on a measuring cylinder of the infiltrometer that measures the conductivity of the liquid along the cylinder with a certain number of electrodes. State of the Art Report Page 4/4