WO2011036342A1

WO2011036342A1 - Portable moisture meter

Info

Publication number: WO2011036342A1
Application number: PCT/FI2010/050730
Authority: WO
Inventors: Nikolai Klausting; Mikko Kuopanportti
Original assignee: Farmcomp Oy
Current assignee: Farmcomp Oy
Priority date: 2009-09-22
Filing date: 2010-09-22
Publication date: 2011-03-31
Anticipated expiration: 2012-03-22
Also published as: FI20095971A0

Abstract

The invention relates to a portable moisture meter comprising material holding means (1) for holding particulate material, a test cell (2), an opening (3) for loading the test cell (2) with particulate material respectively for unloading particulate material, and compacting means (4) for compacting particulate material within the test cell (2). The compacting means (4) includes a threaded cap (5) for co-operation with a threaded portion (6) of the opening (3) for closing the opening (3) and for exerting pressure on particulate material within the test cell (2). The threaded cap (5) comprises a first cap member (10) and a second cap member (11). The moisture meter comprises a self-releasable clutch mechanism (13) for releasable connecting the first cap member (10) and the second cap member (11) together so that the first cap member (10) can be rotated with the second cap member (11).

Description

PORTABLE MOISTURE METER Field of the invention The invention relates to a portable moisture meter as defined in the preamble of independent claim 1.

The invention relates more precisely to portable moisture meters of the type where a compaction step for compaction of a sample of particulate material, the moisture of which is to be measured, is performed by compacting the sample of particulate material in a test cell so that the sample of particulate material has a predefined pressure prior to performing the actual measuring step for measuring the moisture content of the sample of particulate material by measuring the moisture content of the sample of particulate material in a compacted state in the test cell. The measuring of the moisture content of the particulate material in the compacted state in the test cell can for example be made by measuring electrical properties such as conductance or capacitance of the particulate material in the test cell. By particulate material is meant for example, but not excluding other particulate materials, grain in ungrounded and ground state.

Prior to the compaction step a grinding step can be performed to the sample of particulate material to bring the sample of particulate material into a uniform particle size and a step for placing the grinded sample of particulate material in the test cell can be performed. The grinding step can be performed with a separate grinder. Portable moisture meters having integrated grinding means are also known in the art for example from publication EP 0 671 623.

Various arrangements for indicating proper compacting of a sample of particulate material in a test cell or that a sample of particulate material in a test cell has a predefined pressure are known in the art.

Publication US 5,663,650 presents a portable grain moisture meter having a test cell for holding a grain sample to be tested therein. The test cell comprises an opening for loading the test cell with grain respectively for unloading grain from the test cell. This moisture meter comprises a threaded cover means for closing the opening of the test cell and for exerting pressure on grain within the test cell. The threaded cover means includes a threaded cap and comprises a screw movable extending through the threaded cap in response to threading the threaded cap on said test cell for exerting pressure on grain within the test cell. Predetermined pressure is visually indicated by having the screw extending to a position where the screw is even with the top surface of the threaded cap.

Publication US 6,570,395 presents a portable grain moisture measurement device having a test cell for holding a grain sample to be tested therein. The test cell comprises an opening for loading the test cell with grain respectively for unloading grain from the test cell. This moisture meter comprises a threaded cover means for closing the opening of the test cell and for exerting pressure on grain within the test cell. This device has an automatic grain moisture measurement actuation system whenever the compaction of the grain within a test cell of the device is at a preset value and upon such automatic actuation a visual display is activated to indicate that a moisture measurement is being taken as well as the sounding of an audible alarm indicating this measurement to warn the user that further compaction of the grain is unnecessary.

Publication EP 0 617 623 presents an apparatus for measuring moisture content of grain or the like which construction differs from the devices presented in US 5,663,650 and US 6,570,395, because this apparatus does not have a threaded cover means for closing a test cell. This apparatus comprises a body having a grinding mechanism for receiving material to be grinded from a hopper and a compaction chamber i.e. a test cell for receiving ground material from the grinding mechanism. This apparatus comprises a barrel with inner threads co-operating with a coaxially arranged shaft with outer threads so that rotation of the barrel will cause axial movement of the shaft relative to a compression chamber to compact ground grain in the compression chamber. A piston is arranged at the end of the shaft to compact grain in the compression chamber. The barrel is rotatable by means of a manually operable handle secured to a hub having a cap coaxially arranged therein. Between the cap and the barrel a slipping clutch is arranged to allow the cap to slip relative to the barrel when the torque exerted by the cap on the barrel exceeds a predetermined value so as to regulate the amount of compression of the ground grain by the piston in the compression chamber. Objective of the invention

The object of the invention is to provide a portable moisture meter which is easier to use than the prior art portable moisture meters. Short description of the invention

The portable moisture meter of the invention is characterized by the definitions of independent claim 1.

Preferred embodiments of the portable moisture meter are defined in the dependent claims 2 to 31.

The portable moisture meter comprises material holding means and a test cell in said material holding means for holding a sample of particulate material to be tested therein. The test cell comprises an opening for loading the test cell with particulate material respectively for unloading particulate from the test cell. The portable moisture meter comprises also compacting means for compacting a sample of particulate material to be tested within the test cell. The compacting means for compacting a sample of particulate material to be tested within the test cell includes a threaded cap having threads for co-operation with a threaded portion of the opening of the test cell for closing the opening of the test cell and for exerting pressure on a sample of particulate material to be tested within the test cell in response to the threading of the threaded cap on the threaded portion of the opening of the test cell.

The invention is based on using a threaded cap that comprises a first cap member and a second cap member. The threads of the threaded cap for co-operation with the threaded portion of the opening of the test cell are provided on the first cap member. The second cap member is preferable, but not necessarily, mounted at least partly over the first cap member.

The portable moisture meter comprises also pressure sensing means for sensing the pressure in the test cell.

The threaded cap comprises a self-releasable clutch mechanism that is configured for releasable connecting the first cap member and the second cap member together so that the first cap member can be rotated with the second cap member in a first direction for screwing the threaded cap on to the threaded portion of the opening of the test cell for closing the opening of the test cell and for compressing a sample of particulate material to be tested in the test cell. The self-releasable clutch mechanism is configured for disconnecting the first cap member from the second cap member as the threaded cap is screwed on to the threads on the material holding means for closing the opening of the test cell and for compressing a sample of particulate material to be tested in the test cell when the pressure in the test cell sensed by the pressure sensing means exceeds a preset value so that the second cap member after said disconnection can be rotated in relation to the first cap member. This means that, when the first cap member is rotated by means of the second cap member in the first direction for closing the opening of the test cell and for screwing the threaded cap on to the threaded portion on the material holding means for closing the opening of the test cell and for compressing a sample of particulate to be tested in the test cell, the pressure in the test cell can only be raised by means of the threaded cap to a preset pressure level where the pressure sensing means disconnects the first cap member from the second cap member by disconnecting the self-releasable clutch mechanism so that the second cap member can be rotated in relation to the first cap member. This leads to that any additional rotation of the second cap member will not raise the pressure in the test cell because the first cap member will not rotate in relation to the test cell. The result of this is that the pressure in the test cell will always be essentially the same, in other words, that pressure of the sample of particulate material in the test cell will always be the predefined pressure irrespectively of the user of the portable moisture meter.

In a preferred embodiment of the invention the threaded cap comprises a plate means for compressing the sample of particulate in the test cell as the threaded cap is screwed on to the threaded portion of the opening of the test cell and for functioning as a pressure sensing means for sensing the pressure of the sample of particulate material in the test cell. In this preferred embodiment of the invention the plate means is functionally connected with the second cap member so that as the threaded cap is screwed on to the threaded portion of opening of the test cell and the pressure in the test cell increases, the plate means and the second cap member are configured to move together in relation to the first cap member. In this preferred embodiment of the invention the self-releasable clutch mechanism for releasable connecting the first cap member and the second cap member together is arranged between the first cap member and the second cap member so that the self-releasable clutch mechanism is configured for functionally disconnecting the first cap member from the second cap member as the threaded cap is screwed on to the threaded portion on the opening of the test cell and the second cap member together with the plate member has moved to a certain point in relation to the first cap member. In this preferred embodiment of the invention the self-releasable clutch mechanism comprises clutch drive means on the second cap member co-operating with clutch driven means on the first cap member. In this preferred embodiment of the invention the threaded cap is constructed so that the first cap member has an aperture through which the second cap member extends into an inner space formed by the first cap member. In this preferred embodiment of the invention the threaded cap comprises such a plate means that is a part separate from the second cap member that is mechanically connected with the second cap member. In this preferred embodiment of the invention the plate means has a plate portion and a shaft portion and the second cap member has a bore into which the shaft portion of the plate means extends. In this preferred embodiment of the invention the plate means and the second cap member are mechanically connected together in the bore by an external fixture means comprising a locking ring enabling the second cap member to rotate in relation to the first cap member when the self-releasable clutch mechanism is disconnected. In this preferred embodiment of the invention the threaded cap comprises a spring means for biasing the plate means against the sample of particulate material in the test cell as the threaded cap is screwed on to the threaded portion of the opening of the test cell and the pressure in the test cell increases. In this preferred embodiment of the invention the spring means is a compression spring that is located in the inner space formed by the first cap member and that is located in the inner space between the plate means and an inner top surface of the first cap means for biasing the plate means in a direction away from the inner top surface of the first cap means.

The invention can be utilized for example in such portable moisture meters where a predetermined volume of particulate material is put into a test cell for initial grinding and compacting of the ground particulate material and subsequent measuring of the moisture content of the ground particulate material. The invention can also for example be utilized in such applications where the test cell is firstly used for measuring of the volume of the sample of particulate material whereafter the test cell is closed by means of a threaded cap and the sample of particulate material in the test cell is compacted in the test cell by means of the threaded cap and where no subsequent grinding of the sample of particulate material is made prior to the measuring of the moisture content of the sample of particulate material. List of figures

In the following the invention will be described in more detail by referring to the figures, of which

Figure 1 shows a portable moisture meter of a first preferred embodiment of the invention,

Figure 2 shows the material holding means of the portable moisture meter shown in figure 1,

Figure 3 shows the threaded cap of the portable moisture meter shown in figure 1, Figure 4 shows in cut view the portable moisture meter shown in figure 1 cut along line A-A in figure 1 ,

Figure 5 shows in cut view the threaded cap of the portable moisture meter shown in figure 1,

Figure 6 shows in cut view a detail of the threaded cap of the portable moisture meter shown in figure 5 cut along line A-A in figure 5,

Figure 7 shows in cut view a detail of the threaded cap of the portable moisture meter shown in figure 5 cut along line A-A in figure 5,

Figure 8 shows in a portable moisture meter of a second preferred embodiment of the invention,

Figure 9 shows in cut view the portable moisture meter shown in figure 8 cut along line A-A in figure 8,

Figure 10 shows from above a second preferred embodiment of the threaded cap, Figure 11 shows in cut view the threaded cap shown in figure 10 cut along line C-C in figure 10,

Figure 12 shows in cut and perspective view the threaded cap shown in figure 10 cut along line C-C in figure 10,

Figure 13 shows the threaded cap shown in figure 10 in disassembled state,

Figure 14 shows the threaded cap shown in figure 10 in disassembled and partly cut state,

Figure 15 shows the threaded cap shown in figure 10 in cut state, and

Figure 16 shows an embodiment of the portable moisture meter where the threaded cap is provided with an integral sample cup.

Detailed description of the invention

The figures show an example of a portable moisture meter.

The portable moisture meter comprises material holding means 1 and a test cell 2 in said material holding means 1 for holding a sample of particulate material (not shown in the figures) to be tested therein. The test cell 2 comprises an opening 3 for loading the test cell 2 with particulate material respectively for unloading particulate material from the test cell 2.

The portable moisture meter comprises compacting means 4 for compacting a sample of particulate material to be tested within the test cell 2. The compacting means 4 for compacting a sample to be tested within the test cell 2 includes a threaded cap 5 having threads 25 for cooperation with a threaded portion 6 on the opening 3 of the test cell 2 for closing the opening 3 of the test cell 2 and for exerting pressure on a sample of particulate material to be tested within the test cell 2 in response to the threading of the threaded cap 5 on the threaded portion 6 of the material holding means 1. The compacting means 4 are preferably, but not necessarily, manually operable. In the figures the compacting means 4 includes a threaded cap 4 that is manually operable. Alternatively or additionally, the compacting means 4 can comprise means for operating the compacting means 4 by means of an external machine operated tool such as a pneumatic or electric tool. The threaded cap 4 can for example comprise means (not shown) for co-operation with an external machine operated tool such as a pneumatic or electric tool. Alternatively or additionally, the compacting means 4 can be power operated such that the compacting means comprises a motor means (not shown in the figures) for operating the threaded cap 4.

In the moisture meter shown in the figures 1 to 7 the test cell 2 is of the type that is configured for holding a predetermined volume of particulate material that is to be compacted with the compacting means 4. The predetermined volume of particulate material can for example be measured so that particulate material is always filled into the test cell 2 all the way up to the upper end of the opening 3 of the test cell 2.

The portable moisture meter shown in the figures comprises additionally an interface 7 including a display 8 and a keypad 9.

The portable moisture meter comprises moisture measuring means (not shown in the figures) for testing the moisture of the particulate material in the material holding means 1 which moisture measuring means function can be based on measuring a high frequency alternate and/or direct current that is conducted through the sample of particulate material to be tested within the test cell 2. The operation of such devices is described for example in WO 82/04321 (PCT/FI82/00023) which is incorporated here by reference.

The portable moisture meter can additionally comprise first temperature measuring means (not shown in the figures) for measuring the temperature of the particulate material in the test cell 2 and second temperature measuring means (not shown in the figures) for measuring the temperature of the test cell 2 and computer means for calculating a temperature compensating factor for compensating said moisture measuring means based on the differential of the temperature sensed by the first temperature measuring means and the second temperature measuring means.

The threaded cap 5 comprises a first cap member 10 and a second cap member 11. The threads 25 of the threaded cap 5 for co-operation with the threaded portion 6 of the opening 3 of the test cell 2 are provided on the first cap member 10. In the embodiments shown in the figures, the second cap member 11 is mounted at least partly over the first cap member 10 so that the first cap member 10 can be considered to form an inner cap member and so that the second cap member 11 can be considered to form an outer cap member.

The portable moisture meter comprises pressure sensing means 12 for sensing the pressure of the sample of particulate material in the test cell 2.

The threaded cap 5 comprises a self-releasable clutch mechanism 13 that is configured for releasable connecting the first cap member 10 and the second cap member 11 together so that the first cap member 10 can be rotated with the second cap member 11 in the first direction for screwing the threaded cap 5 on to the threaded portion 6 of the opening 3 of the test cell 2 for closing the opening 3 of the test cell 2 and for compressing a sample of particulate material to be tested in the test cell 2. The self-releasable clutch mechanism 13 is configured for disconnecting the first cap member 10 from the second cap member 11 as the threaded cap 5 is screwed on to the threaded portion 6 of the opening 3 of the test cell 2 for compressing a sample of particulate material to be tested in the test cell 2 when the pressure in the test cell 2 sensed by the pressure sensing means 12 exceeds a preset value so that the second cap member 11 after said disconnecting can be rotated , preferably be rotated freely, in relation to the first cap member 10. In the figures the pressure sensing means 12 for sensing the pressure in the test cell is configured for sensing the pressure of the sample of particulate material in the test cell 2. Alternatively or additionally a pressure limiting means (not shown in the figures) may be provided that is configured for co-operation with the pressure sensing means 12 in such way that the pressure sensing means 12 is configured for touching the pressure limiting means as the threaded cap 5 is screwed on to the threaded portion 6 of the opening 3 of the test cell 2 for compressing a sample of particulate material to be tested in the test cell 2 when the pressure in the test cell 2 sensed by the pressure sensing means 12 exceeds a preset value so that the second cap member 11 after said disconnecting can be rotated in relation to the first cap member 10. Such a pressure sensing means is preferably, but not necessarily, arranged inside the test cell 2.

The threaded cap 5 of the portable moisture meter shown in the figures comprises a plate means 14 for compressing the sample of particulate material in the test cell 2 as the threaded cap 5 is screwed on to the threaded portion 6 on the opening 3 of the test cell 2 and for functioning as a pressure sensing means 12 for sensing the pressure of the sample of particulate material in the test cell 2. The test cell 2 has preferably, but not necessarily, a cylindrical configuration and plate means 14 has preferably, but not necessarily, a diameter that is smaller than the diameter of the test cell 2.

In the figures the threaded cap 5 comprises a plate means 14 for compressing the sample of particulate material in the test cell 2 as the threaded cap 5 is screwed on to the threaded portion 6 of the opening 3 of the test cell 2 and for functioning as a pressure sensing means 12 for sensing the pressure of the sample of particulate material in the test cell 2, which plate means 14 is functionally connected with the second cap member 11 so that as the threaded cap 5 is screwed on to the threaded portion 6 of the opening 3 of the test cell 2 and the pressure in the test cell 2 increases, the plate means 14 and the second cap member 11 are configured to move together in relation to the first cap member 10. In the figures the self-releasable clutch mechanism 13 for releasable connecting the first cap member 10 and the second cap member 11 together is arranged between the first cap member 10 and the second cap member 11 so that the self-releasable clutch mechanism 13 is configured for disconnecting the first cap member 10 from the second cap member 11 as the threaded cap 5 is screwed on to the threads on the material holding means 1 and the second cap member 11 together with the plate means 14 has moved axially to a certain point in relation to the first cap member 10. In the figures the self- releasable clutch mechanism 13 comprises clutch drive means 15 on the second cap member 1 1 co-operating with clutch driven means 16 on the first cap member 10 so that the first cap member 10 can be rotated with the second cap member 11 in the first direction. In the figures the clutch drive means 15 on the second cap member 11 and the clutch driven means 16 on the first cap member 10 are formed by co-operating formations 17 on the second cap member 11 and correspondingly on the first cap member 10. In the figures the threaded cap 5 is constructed so that the first cap member 10 has an aperture 18 through which the second cap member 11 extends into an inner space (not marked with a reference numeral) formed by the first cap member 10. In the figures the threaded cap 5 comprises a plate means 14 that is a part separate from the second cap member 11 and that is connected with the second cap member 11. In the figures the plate means 14 has a plate portion 19 and a shaft portion 20 and the second cap member 11 has a bore 21 into which the shaft portion 20 of the plate means 14 extends. In the figures the plate means 14 and the second cap member 11 are joined together in the bore 21 by an external fixture means 26.

In the embodiment shown figures 4 to 9 the external fixture means 26 comprises a locking ring enabling the second cap member 11 to rotate in relation to the first cap member 10 when the self-releasable clutch mechanism 13 is disconnected.

In the embodiment shown in figures 10 to 13 the bore 21 in the second cap member 11 extends through the second cap member 11. In the embodiment shown in figures 10 to 13 the external fixture means 26 comprises a screw that is screwed into a hole 28 in the shaft portion 20 of the plate means 14.

In the figures the threaded cap 5 comprises a spring means 22 for biasing the plate means 14 against the sample of particulate material in the test cell 2 as the threaded cap 5 is screwed on to the threaded portion 6 of the opening 3 of the test cell 2 and the pressure in the test cell 2 increases. In the figures the spring means 22 is a compression spring that is located in the inner space formed by the first cap member 10 and that is located in the inner space between the plate means 14 and a inner top surface of the first cap member 10 for biasing the plate means 14 in a direction away from the inner top surface of the first cap member 10.

The plate means 14 for compressing the sample of particulate material in the test cell 2 as the threaded cap 5 is screwed on to the threaded portion 6 of the opening 3 of the test cell 2 and for functioning as a pressure sensing means 12 for sensing the pressure of the sample of particulate material in the test cell 2 may be provided with grinding means 23 configured for grinding the sample of particulate material in the test cell 2 as the threaded cap 5 is screwed on to the threads on the material holding means 1. Also the test cell 2 may be provided with grinding means 23 configured for grinding the sample of particulate material in the test cell 2 as the threaded cap 5 is screwed on to the threaded portion 6 of the material holding means 1. Such a portable moisture meter is shown in figures 8 and 9.

The threaded cap 5 may be provided with grinding means 23 configured for grinding the sample of particulate material in the test cell 2 as the threaded cap 5 is screwed on to the threaded portion 6 of the material holding means 1.

The portable moisture meter may be provided with an elongated handle 24 for rotating the second cap member 11 as is shown in figures 8 and 9. The elongated handle can be fixedly attached to the second cap member 11 or releasably attachable to the second cap member 11. Especially if the threaded cap 5 and/or the test cell 2 may is provided with grinding means 23 such an elongated handle can be of advantage to make the grinding easier.

The portable grain moisture meter may be provided with audio means, visual means, or audiovisual means to indicate that the self-releasable clutch mechanism 13 has disconnected the first cap member 10 from the second cap member 11.

The portable grain moisture meter may comprise a ratchet mechanism 29 for releasable connecting the first cap member 10 and the second cap member 11 together so that the first cap member 10 can be rotated with the second cap member 11 in a second direction that is opposite to the first direction for screwing the threaded cap 5 off the threaded portion 6 of the opening 3 of the test cell 2 for opening the opening 3 of the test cell 2 and for removing the threaded cap 5 from the test cell 2 when the self-releasable clutch mechanism (13) has disconnected the first cap member 10 from the second cap member 11.

In the figures the portable grain moisture meter has a ratchet mechanism 29 comprising flexible projections 30 provided at a top face of the first cap member 10 for co-operation with recesses 31 provided at a lower face of the second cap member 11 so that the flexible projections 30 will come into engagement with the recesses 31 when the second cap member 11 is rotated in the second direction when the self-releasable clutch mechanism 13 has disconnected the first cap member 10 from the second cap member 11, and so that the flexible projections 30 will come out of engagement with the recesses 31 when the second cap member 11 is rotated in the first direction when the self-releasable clutch mechanism 13 has disconnected the first cap member 10 from the second cap member 11. Alternatively or additionally, the portable moisture meter may comprise a ratchet mechanism 29 that comprises recesses 31 provided at a top face the second cap member 11 for co-operation with flexible projections 30 provided at a lower face of the first cap member 10 so that the flexible projections 30 will come into engagement with the recesses 31 when the second cap member 11 is rotated in the second direction when the self- releasable clutch mechanism 13 has disconnected the first cap member 10 from the second cap member 11, and so that the flexible projections 30 will come out of engagement with the recesses 31 when the second cap member 11 is rotated in the first direction when the self- releasable clutch mechanism 13 has disconnected the first cap member 10 from the second cap member 11.

The portable moisture meter can have a threaded cap 5 that is provided with an integral sample cup 27 having a volume essentially corresponding to the volume of a sample of particulate material to be tested within the test cell 2. By using the integral sample cup 27 can a correct volume of a sample of particulate material to be tested within the test cell 2 be formed prior loading the sample into the test cell 2. A such integral sample cup 27 is preferably, but not necessarily, provided on the outer surface of the second cap member 11 as shown in figure 16.

The portable moisture meter can have a threaded cap 5 that is provided with a gear mechanism between the first cap member 10 and the second cap member 11, wherein the gear mechanism is operable by rotating the second cap member 11 and wherein the gear mechanism is configured for rotating the first cap member 10 in response to rotation of the second cap member 11. The gear mechanism can be in the form of a planetary gear mechanism. The gear mechanism is preferably, but not necessarily, in the form of a reduction gear mechanism so that the first cap member 10 rotates slower than the second cap member 11.

It is apparent to a person skilled in the art that as technology advances, the basic idea of the invention can be implemented in various ways. The invention and its embodiments are therefore not restricted to the above examples, but they may vary within the scope of the claims.

List of reference numerals

1. Material holding means

2. Test cell

3. Opening

4. Compacting means

5. Threaded cap

6. Threaded portion

7. Interface

8. Display

9. Keypad

10. First cap member

11. Second cap member

12. Pressure sensing means

13. Self-releasable clutch mechanism

14. Plate means

15. Clutch drive means

16. Clutch driven means

17. Co-operating formations

18. Aperture

19. Plate portion

20. Shaft portion

21. Bore

22. Spring means

23. Grinding means

24. Elongated handle

25. Threads

26. External fixture means

27. Integral sample cup

28. Hole

29. Ratchet mechanism

30. Flexible projections

31. Recesses

Claims

1. A portable moisture meter for determining the moisture content of particulate material, comprising

material holding means (1) for holding particulate material,

a test cell (2) in said material holding means (1) for holding a sample of particulate material to be tested therein, wherein said test cell (2) having an opening (3) for loading the test cell (2) with particulate material respectively for unloading particulate material from the test cell (2),

compacting means (4) for compacting a sample of particulate material to be tested within the test cell (2), and

moisture measuring means for testing the moisture of the sample of particulate material in the material holding means (1),

wherein the compacting means (4) for compacting a sample of particulate material to be tested within the test cell (2) includes a threaded cap (5) having threads (25) for co-operation with a threaded portion (6) of the opening (3) of the test cell (2) for closing the opening (3) of the test cell (2) and for exerting pressure on a sample of particulate material to be tested within the test cell (2) in response to the threading of the threaded cap (5) on the threaded portion (6) of the test cell (2),

characterized

by the threaded cap (5) comprising a first cap member (10) and a second cap member

(11),

by the threads (25) of the threaded cap (5) for co-operation with the threaded portion (6) of the opening (3) of the test cell (2) being provided on the first cap member (10),

by pressure sensing means (12) for sensing the pressure in the test cell (2), and by a self-releasable clutch mechanism (13) that is configured for releasable connecting the first cap member (10) and the second cap member (11) together so that the first cap member (10) can be rotated with the second cap member (1 1) in a first direction for screwing the threaded cap (5) on to the threaded portion (6) of the opening (3) of the test cell (2) for closing the opening (3) of the test cell (2) and for compressing a sample of particulate material to be tested in the test cell (2), and which self-releasable clutch mechanism (13) is configured for disconnecting the first cap member (10) from the second cap member (1 1) as the threaded cap (5) is screwed on to the threaded portion (6) of the opening (3) of the test cell (2) for closing the opening (3) of the test cell (2) for compressing a sample of particulate material to be tested in the test cell (2) when the pressure in the test cell (2) sensed by the pressure sensing means (12) exceeds a preset value so that the second cap member (11) after said disconnection can rotate in relation to the first cap member (10).

2. The portable moisture meter according to claim 1, characterized in that the threaded cap (5) comprising a plate means (14) for compressing the sample of particulate material in the test cell (2) as the threaded cap (5) is screwed on to the threaded portion (6) on the opening (3) of the test cell (2) and for functioning as a pressure sensing means (12) for sensing the pressure of the sample of particulate material in the test cell (2).

3. The portable moisture meter according to claim 2, characterized

in that the test cell (2) has a cylindrical configuration, and

in that the diameter of the plate means (14) is smaller than the diameter of the test cell (2).

4. The portable moisture meter according to claim 2 or 3, characterized

in that the plate means (14) being functionally connected with the second cap member (11) so that as the threaded cap (5) is screwed on to the threaded portion (6) on the opening (3) on the material holding means (1) and the pressure in the test cell (2) increases, the plate means (14) and the second cap member (11) are configured to move together in relation to the first cap member (10), and

in that the self-releasable clutch mechanism (13) for releasable connecting the first cap member (10) and the second cap member (11) together is arranged between the first cap member (10) and the second cap member (11) so that the self-releasable clutch mechanism (13) is configured for disconnecting the first cap member (10) from the second cap member (11) as the threaded cap (5) is screwed on to the threaded portion (6) of the opening (3) of the test cell (2) and the second cap member (11) together with the plate means (14) has moved to a certain point in relation to the first cap member (10).

5. The portable moisture meter according to claim 4, characterized in that the self- releasable clutch mechanism (13) comprises clutch drive means (15) on the second cap member (11) co-operating with clutch driven means on the first cap member (10).

6. The portable moisture meter according to claim 5, characterized in that the clutch drive means (15) on the second cap member (11) and the clutch driven means (16) on the first cap member (10) are formed by co-operating formations (17) on the second cap member (11) and correspondingly on the first cap member (10).

7. The portable moisture meter according to any of the claims 2 to 6, characterized by the threaded cap (5) comprising a spring means (22) for biasing the plate means (14) against the sample of particulate material in the test cell (2) as the threaded cap (5) is screwed on to the threaded portion (6) on the opening (3) of the test cell (2) and the pressure in the test cell (2) increases.

8. The portable moisture meter according to claim 7, characterized

in that the spring means (22) is a compression spring that is located in an inner space formed by the first cap member (10), and

in that the spring means (22) is located in the inner space between the plate means (14) and an inner top surface of the first cap member (10) for biasing the plate means (14) in a direction from the inner top surface of the first cap member 11.

9. The portable moisture meter according to any of the claims 2 to 8, characterized in that the first cap member (10) comprises an aperture (18) through which the second cap member (11) extends into an inner space formed by the first cap member (10).

10. The portable moisture meter according to any of the claims 2 to 9, characterized

in that the plate means (14) is a part separate from the second cap member (11), and in that the plate means (14) and the second cap member (11) are connected together.

11. The portable moisture meter according to claim 10, characterized

in that the plate means (14) has a plate portion (19) and a shaft portion (20), and in that the second cap member (11) has a bore (21) into which the shaft portion (20) of the plate means (14) extends.

12. The portable moisture meter according to claim 1 1, characterized in that the plate means (14) and the second cap member (11) are joined together in the bore (21) by an external fixture means (26).

13. The portable moisture meter according to claim 12, characterized in that the external fixture means (26) comprises a locking ring enabling the second cap member (11) to rotate in relation to the first cap member (10) when the self-releasable clutch mechanism (13) is disconnected.

14. The portable moisture meter according to claim 12 or 13, characterized

in that the bore (21) extends through the second cap member (11),

in that the shaft portion (20) of the plate means (14) is provided with a hole (28), and in that the external fixture means (26) comprises a screw that located in the bore (21) and that is screwed into the hole (28) in the shaft portion (20) of the plate means (14) to connect the second cap member (11) and the plate means (14).

15. The portable moisture meter according to any of the claims 2 to 14, characterized by the plate means (14) being provided with grinding means (23) configured for grinding the sample of particulate material in the test cell (2) as the threaded cap (5) is screwed on to the threads on the material holding means (1).

16. The portable moisture meter according to any of the claims 1 to 15, characterized by the threaded cap (5) being provided with grinding means (23) configured for grinding the sample of particulate material in the test cell (2) as the threaded cap (5) is screwed on to the threaded portion (6) of the material holding means (1).

17. The portable moisture meter according to any of the claims 1 to 16, characterized by the test cell (2) being provided with grinding means (23) configured for grinding the sample of particulate material in the test cell (2) as the threaded cap (5) is screwed on to the threaded portion (6) of the material holding means (1).

18. The portable moisture meter according to any of the claims 1 to 17, characterized by the test cell (2) being configured for holding a predetermined volume of particulate material that is to be compacted with the compacting means (4).

19. The portable moisture meter according to any of the claims 1 to 18, characterized

by first temperature measuring means for measuring the temperature of the sample of particulate material in the test cell (2),

by second temperature measuring means for measuring the temperature of the test cell

(2), and

by computer means for calculating a temperature compensating factor for compensating said moisture measuring means based on the differential of the temperature sensed by the first temperature measuring means and the second temperature measuring means.

20. The portable moisture meter according to any of the claims 1 to 19, characterized by an elongated handle (24) for rotating the second cap member (11).

21. The portable moisture meter according to any of the claims 1 to 20, characterized by the second cap member (11) being mounted at least partly over the first cap member (10) so that the first cap member (10) forms an inner cap member and the second cap member (11) forms an outer cap member.

22. The portable moisture meter according to any of the claims 1 to 21, characterized by the compacting means (4) are manually operable.

23. The portable moisture meter according to any of the claims 1 to 22, characterized by the pressure sensing means (12) for sensing the pressure in the test cell (2) being configured for sensing the pressure of the sample of particulate material in the test cell (2).

24. The portable moisture meter according to any of the claims 1 to 23, characterized by audio means, visual means, or audiovisual means to indicate that the self-releasable clutch mechanism (13) has disconnected the first cap member (10) from the second cap member (11).

25. The portable moisture meter according to any of the claims 1 to 24, characterized by a ratchet mechanism (29) for releasable connecting the first cap member (10) and the second cap member (11) together so that the first cap member (10) can be rotated with the second cap member (11) in a second direction for screwing the threaded cap (5) off the threaded portion (6) of the opening (3) of the test cell (2) for opening the opening (3) of the test cell (2) and for removing the threaded cap (2) from the threaded portion (6) of the opening (3) of the test cell (2) when the self-releasable clutch mechanism (13) has disconnected the first cap member (10) from the second cap member (11).

26. The portable moisture meter according to claim 25, characterized by the ratchet mechanism (29) comprises flexible projections (30) provided at the first cap member (10) for cooperation with recesses (31) provided at the second cap member (11) so that the flexible projections (30) will come into engagement with the recesses (31) when the second cap member (11) is rotated in the second direction when the self-releasable clutch mechanism (13) has disconnected the first cap member (10) from the second cap member (11), and so that the flexible projections (30) will come out of engagement with the recesses (31) when the second cap member (11) is rotated in the first direction when the self-releasable clutch mechanism (13) has disconnected the first cap member (10) from the second cap member (1 1).

27. The portable moisture meter according to claim 25 or 26, characterized by the ratchet mechanism (29) comprises recesses (31) provided at the second cap member (11) for cooperation with flexible projections (30) provided at the first cap member (10) so that the flexible projections (30) will come into engagement with the recesses (31) when the second cap member (11) is rotated in the second direction when the self-releasable clutch mechanism (13) has disconnected the first cap member (10) from the second cap member (11), and so that the flexible projections (30) will come out of engagement with the recesses (31) when the second cap member (11) is rotated in the first direction when the self-releasable clutch mechanism (13) has disconnected the first cap member (10) from the second cap member (1 1).

28. The portable moisture meter according to any of the claims 1 to 27, characterized by the threaded cap (5) being provided with an integral sample cup (27) having a volume essentially corresponding to the volume of a sample of particulate material to be tested within the test cell (2)·

29. The portable moisture meter according to claim 28, characterized by the integral sample cup (27) being provided on the outer surface of the second cap member (11).

30. The portable moisture meter according to any of the claims 1 to 29, characterized by a gear mechanism between the first cap member (10) and the second cap member (11), wherein the gear mechanism is operable by rotating the second cap member (11) and wherein the gear mechanism is configured for rotating the first cap member (10) in response to rotation of the second cap member (11).

31. The portable moisture meter according to claim 30, characterized by the gear mechanism is in the form of a planetary gear mechanism.