IL25254A - Moisture-sensing device and control system utilizing same - Google Patents

Description

0 D ID 1 J Π 3 D J D 9 1 I Ι Π 1 Π Ι 0 Π Π Π 1 D DEVICE AND SYSTEM SABS In I The present invention relates to a moisture device and to a control system utilizing One application for such a device and system is in the measurement of smil to provide indication of the quantity of moisture in the to ate a valve or other object in accordance with the amount of moisture The invention therefore finds particular application in soil irrigation Various types of moisture sensing devices and trol systems have Examples are tion tensionmeters and electrical For the most such devices and systems are complicated and costly to An object of the present invention is to provide a moisture sensing device which is very simple in struction and therefore inexpensive to Another object of the invention is to provide a control system including the novel moisture sensing The moisture sensing device of the present tion is a The control system in which the moisture sensing device is used may be or Described below are a simple hydraulic system and a simple electrical s According to the present there is provided a moisture sensing device characterized in that it includes a member which swells in proportion to the amount of moisture absorbed expansible chamber operatively associated with respect to said member so as to be expanded or contracted in proportion the amount of swelling of said said expansible chamber being disposed or constituted a cavity formed in said and absorbing liquid in said chamber pLaceable by the expansion or contraction of said said expansible chamber including a tube in which said liquid is The invention also provides control systems including the moisture sensing device described In one of the described the system includes a valve or other object controlled by the moisture sensing and a hydraulic line connected to the valve or other object for controlling same in accordance with the displacement of the In another described the control system includes an electrical circuit in which a pair of contacts are the displaceable liquid being ally conductive and causing the bridging of the pair of electrical contacts when the liquid is displaced a predetermined Further features and advantages of the invention will be apparent from the description The invention is herein described with reference to the accompanying drawings which by way of example several preferred embodiments of the In the 1 is a longitudinal sectional partly broken of a moisture sensing device constructed in accordance with the 2 is a side elevational partly in section and partly broken of another form of moisture sensing device constructed in accordance with the and also of a control system including such schematically illustrates another form of control system in which the devices of 1 or 2 may be With reference first to 1 there is shown a moisture sensing device or detector including a moisture absorbing member in the form of a cylindrical wooden block 2 tapered at one end 4 to facilitate its totally or partially embedded in the ground sensing ground Block 2 is formed with an internal cavity 6 in which is disposed an expansible chamber the latter being in the form of a bellows made plastic or other resilient One end of the bellows 8 normally rests against the bottom surface 10 of cavity 6 and the opposite end of the bellows includes a tube 12 having a or ing longitudinally Bellows 8 contains a liquid such as colored which is adapted to be displaced vithin tube 12 in accordance with the amount of expansion or contraction of the An housing of drawn is attached to wooden block 2 by means of a collar Housing 16 encloses the upper end of tube 12 and is formed with an elongated slot 20 through which the and particularly the level of the liquid within bore may be markings 22 are applied adjacent to slot 20 so as to indicate the of maisture sensed as determined by the level of ths liquid within bore Housing 16 is onto collar 18 and similarly the latter collar is onto vrooden block If fasteners may be used for attaching these A fastener 24 is provided so as to fix tube 12 with respect to block This fastener is used for making preliminary adjustments to the Raising tube 12 causes the bellows 8 to expand thus lowering the normal level of the liquid within the and lowering the tube 1 causes the bellows to traet thus raising the normal level of the liquid within the The operation of the device will be apparent from the foregoing Wooden block 2 is or totally embedded in the with the housing 16 projecting above the ground so that the upper end of tube 12 be viewed through slot Block 2 in proportion to the amount of moisture absorbed by it from the Swelling of the block causes the lower surface 10 of cavity 6 to contract bellows 8 and thereby to displace upwardly the liquid within the bellows and within tube As the amount of moisture in the ground so does the amount of swelling of the and the level of the liquid will drop in tube the tube by virtue of its serves as a hydraulic amplifier of the displacement of the liquid within the The liquid within tube 12 will a level indicative of the amount of swelling of wooden block and thereby of the amount of moisture in the while the device of 1 is used only for providing an indication of the amount of moisture it will be appreciated that it could also be used for trolling an such as a in accordance with the amount of moisture Such a system is shown in the tube 32 from the bellows wooden block is preferably made of such as copper or aluminum and extends through a cap closing the upper end of the wooden A glass tube 38 having a smaller diameter nected to a valve which is used to control a water sprinkler 48 or another irrigating such an underground Tube 38 may also be graduated to indicate the amount of moisture The displacement of the liquid within tube 32 thus controls water sprinkler this displacement being transmitted through hydraulic line 44 to the control valve A very simple and inexpensive control system is thereby 3 illustrates another form of control system that may be used with the novel moisture sensing the displaceable liquid is electrically for it could be of mercury salt This liquid is displaced in the manner described below within the bore 142 of a tube 144 so as to bridge a pair of trical contacts 146 and 148 in this bore when the liquid rises to the level of contact These contacts 146 and 148 are in an electrical circuit used to control a valve or other schematically designated It will be appreciated that many other variations and applications of the disclosed embodiments could be For instead of using a bellows the cavity 6 itself within the wooden 2 may serve as the expansible since it expands and contracts in proportion to the amount of swelling of the wooden In materials other than wood could be used for block for example asbestos other forms of control systems could be one of the cell circuits for sensing the level of the insufficientOCRQuality

Claims (9)

WHAT IS CLAIMED IS :

1. A moisture sensing device characterized in that it includes a rigid moisture-absorbing member which swells in proportion to the amount of moisture absorbed by it, an expansible chamber operatively associated with respect to said member so as to be expanded or contracted in proportion to the amount of swelling of said member, said expansible chamber being disposed in, or constituted by, a cavity formed in said moisture-absorbing member, and a liquid in said chamber displaceable by the expansion or contraction of said chamber, said expansible chamber including a tube in which said liquid is displaced.

2. A moisture sensing device according to Claim 1, further characterized in that said moisture-absorbing member is made of wood.

3. A moisture sensing device according to either of Claims 1 or 2, further characterized in that said expansible chamber is a bellows made of rubber, plastic or other resilient material.

4. A moisture sensing device according to any one of Claims 1-3» further characterized in that said tube is graduated to indicate the amount of displacement of said liquid therein, thereby providing an indication of the amount of moisture absorbed by said member.

5. A moisture sensing device {according to any of Claims 1-4, further characterized in that said moisture-absorbing member is of a cylindrical shape tapered at one end enabling it to be totally or partially embedded in the ground for sensing ground moisture.

6. A moisture-sensitive control system including a moisture sensing device according to any of Claims 1-5» a vaAve or other object controlled thereby, and a hydraulic line connected to said valve or other object for controlling same in accordance with the displacement of said liquid.

7. A moisture-sensitive eontrol system including a moisture sensing device according to any of Claims 1-5, a valve or other object controlled thereby, and an electrical circuit controlled by the displacement of said liquid for controlling said valve or other object.

8. A moisture-sensttive control system according to Claim 7» further characterized in that said electrical circuit includes a pair of contacts, said displaceable liquid being electrically conductive and causing the bridging of said pair of electrical contacts when the liquid is displaced a predetermined amount.

9. A moisture sensing device substantially as described with reference to and as illustrated in the arcompanying drawings* COHEN ZEDEK & SPISBACH P.O.BOX 1169, TEL AVIV ATTORNEYS FOR APPLICANT.