CA1059596A - Proportioning moisture sensing device for refrigeration systems - Google Patents
Proportioning moisture sensing device for refrigeration systemsInfo
- Publication number
- CA1059596A CA1059596A CA206,149A CA206149A CA1059596A CA 1059596 A CA1059596 A CA 1059596A CA 206149 A CA206149 A CA 206149A CA 1059596 A CA1059596 A CA 1059596A
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- plates
- moisture
- cathode
- anode
- desiccant material
- Prior art date
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Abstract
ABSTRACT OF THE DISCLOSURE
A sensing device for detecting the presence of dissolved and undis-solved water or water related contaminants in a refrigeration system even when the water or contaminants are present at low concentrations in order to acti-vate an audio-visual signal, deactivate the system or otherwise provide a warning or corrective action before the occurrence of damage to the system.
The device is in the form of a probe insertable into a flow line or flow path of a refrigeration system and includes an absorbent material positioned between and in intimate contact with an anode and cathode with constant pressure maintained on the anode and cathode for retaining there components in contact with the absorbent or desiccant.
A sensing device for detecting the presence of dissolved and undis-solved water or water related contaminants in a refrigeration system even when the water or contaminants are present at low concentrations in order to acti-vate an audio-visual signal, deactivate the system or otherwise provide a warning or corrective action before the occurrence of damage to the system.
The device is in the form of a probe insertable into a flow line or flow path of a refrigeration system and includes an absorbent material positioned between and in intimate contact with an anode and cathode with constant pressure maintained on the anode and cathode for retaining there components in contact with the absorbent or desiccant.
Description
~os~s~
The present invention generally relate4 to moisture sensing devices and more particularly a sensing device for use in refrigeration systems for detecting the presence of moisture or moisture related contaminants in the refrigera-tion system to enable corrective action to be taken prior to the occurence of damage to the system.
One of the major problems occurring in refrigeration systems is damage caused by moisture or water in the refrig-eration system. Frequently, water, and water-related con-taminants such as acids in the refrigerant liquid, gas, or oil will cause damage to various components of the refrigera-tion system and has been the cause of many major repairs.
This problem has been recognized and some efforts have been made to detect contaminants in the refrigeration system. U,S.
f Patent No. 3,288,960 issued November 29, 1966 to E. J. Miller discloses electrical contacts in the flow path of a fluid to provide a warning or rendèr the system lnoperative when the quality or characteristics of the fluid in the flow path has changed. Other patents disclose electrical circuits in which absorbent members are associated with electrodes to control an electrical circuit in response to moisture absorbed by the absorbent, U.S. Patent No. 3,671,912 issued ~une 20, 1972 to L. S. LaSota discloses an exemplary arrangement of this type. However, such prior devices perform after contact with undissolved contaminants such as moisture to dissolve a soluble material, acid to attach the twisted wires or water in insul-ating oil and do not solve the problem of detecting small ~ quantities or concentrations of moisture and contaminants that - may become absorbed in a refrigerant system which is necessary 29 in order to sense a condition before it causes damage.
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105~S~3~
, The present invention relates to a sensing devlce for detecting the presence of low concentrations of moisture and moisture related contaminants in refrigerant systems comprising an anode and cathode disposed in spaced relation in the flow path of the refrigerant system and adapted to be connected into an electrical circuit, absorbent means disposed between the anode and cathode and in the flow path with the absorbent means including material capable of change of electrical conductivity in response to moisture absorption including dissolved and undissolved moisture and moisture related contaminants in the refrigerant system whereby changes of conductivity will enable electrical flow in the circuit for enabling detectlon o the presence of moisture or moisture related contaminants in the refrigerant system, the anode and cathode being in the form of spaced plates spaced from each other by desiccant material, means maintaining contact pressure between the plates and desiccant material thereby maintaining electrical contact with changes in electrical conductivity of the desiccant material being proportional to absorption of moisture or moisture related contaminants from the refrigerant system.
Figure 1 is a schematic illustration of a refrigeration system with the sensing device of the present invention incorporated therein.
Figure 2 is an elevational view of the sensing device installed in a flow line of the refrigeration system.
Figure 3 is a longitudinal, sectional view, on an enlarged scale, taken substantially upon a plane passing along section line 3-3 of Pig. 2 illustrating the specific structural details of the probe, anode, cathode, absorbent material, retainer and related structure.
Figure 4 is a transverse, sectional view taken sub-stantially upon a plane passin~ along section line 4~4 of Fig.
3 illustrating further structural details of the absorbent ~ - 2 -C dap/t;h, ,, .
- ~os~59~
material and retainer therefor.
Flgure 5 is a sectional view similar to Fig. 2 illustrating another embodiment of the sen~ing device.
Figure 6 is a sectional view illustrating the specific details of the embodiment of the device illustrated in Fi~. S.
Figure 1 illustrates schematically a standard refrigeration system including a compressor 10, water-cooled condenser 12, liquid refrigerant, dryer :, '7 , - 2a -dap/,c~
., , , - . ` ~ , ~
5~ti 14, expansion tevlce 16 and evaporator assombly 18 whlch 1~ shown as the type for chllllng or cooling water or other llquid heat exchang~ medlum. The pro-portlonal sensing devlce of the present invention i8 generally te~lgnated by the numeral 20 and i8 illuatrated in the llquld r~friger~nt llne between the receiver-dryer and expansion dqvlce. However, a~ set forth in more tetall hereinafter, the senslng devlce may have many locatlon~ d~pending upon the particular refrigeration system lnvolved. A~ lllustra~ed, the ~ensing tevice may be lncorporated into the refrigera~t flow path 22 by insertio~ into the branch 24 of a stantart T coupl~ng 26.
The sen~lng device 20 ehow~ in Fig~. 2-4 lnclutes a screw-threaded body 28 that i8 externally thrested a~t i~ tetachably engaged with the inter-nally threatet branch 24 of the coupling 26. The boty 28 lnclutes a polygonal wrench receiving area 30 to facllltate installation of the devlce. A cathode wire 32 is connected to the boty 28 by a seandart screw-type connection 34 80 that the wire 32 19 electrically connectet to the boty 28 which i8 of conductive material. The cathode ~ire 32 may be connected to any portlon of a totally grountet refrigeration system wlth the connection to body 28 only being neces-sary when the probe assembly 20 18 screwed into nonconducting material.
Dlsposet longitudinally through the body 28 which is provided with a - 20 cylintrlcal internsl bore is an insulati~ng ~leeve 26 of porcelaln, plastic or other sultable insulating materlal with the ends of the sleeve 36 extending both lnwardly of the body 28 and outwardly thereof. Extending longltudinally through the in~ulating sleeve 36 is a contuctor rod or electrode 38 which extend~ beyond each e~d of the insulating sleeve 36. The outer end of the electrode 1~ CDnnectet to an electric~l conductor 40 by a stantard screw-type c connection 42 thus electricslly connecting the conductor 40 to the electrode 38 with the inner end of the electrode tending beyond the inner end of the insulating sleeve 36. Thus, the conductors 32 and 40 are insulated from each other and the conductive boty 28 is insulated from the conductive rod or ` 30 electrode 38.
- The rod 38 i8 provided with a threaded end 39 which recelves an adapter 44 having internal threaded bores 46 formed therein. The outer bore 46 1.(~5~59~
threadedly rece~ves an externally thre6ded rod 48 whlch ensbleo ~arlstlon ln the length Qf the probe or tepth o~ the probe by threading the rod 48 lnto and out of the threatet bore 46. A lock nut 50 is psovidet on the threadet rot 48 to lock it i~ sd~ustet posltion.
The threaded rod 48 lncludes a perlpheral boss or ~houlder 52 thereon snd an axlally extending rod 54 pro~ecti~g therefro~ ln oppo~ite relation to the threaded rod 48. The free end of the rod 54 i3 externally threaded at 56 for receiving a pressure ad~usting and retaining nut 58. Positionet between the shoulder 52 and the nut 58 is a cathode disc 60 snd 8n anote disc 62 wlth the anode dl3c 62 restlng against the nut 58 and placed dlrectly on the threaded rod 54. The cathode tisc 6Q la spaced froM the shoulder 52 ~y an in~ulating disc 64 a~d insulated and spaced from the threadod rot 54 by a~ ln3ulating sleeve 66 whlch may be integral wlth or ~eparate from the di~c 64 And constructed of plast$c or other insulating ~aterial.
Interposed bet~een the cathode disc 60 and the anode di~c 62 is a layer of desiccant materlal 68 which i8 ~oisture absorbent and may be in particu-late form ~uch a~ granules or crystals of silica gel, or flilic~ gel ln pellet or powder form or any other hygroscopic materlal that changes it~ electrical characterlstics with the absorption of moisture. The desiccant material 68 is reta~ned ln place between the discs 60 and 62 by a fabric ring or gro~met 70 which ha~ a cross-~ectional area generally equal to the ~pace between the disc~ 60 ~nd 62 and forms an an~ular poroua clo~ure for the ~pace bet~een the discs 60 and 62 thereby retaining the desiccant material within the annular space definet by the tiscs 60 and 62 ant by the external ~urface of the rod 54 and the in~ernal surface of the an~ular fabric ring 70. The an~ular fabric ring 70 i8 of a porous fabric matersl which enables moi~ture or moi~ture con-ta~lnants to be absorbed by the desiccant materlal 68. The ~abric ring 70 also serYes as a ~trainer to prevent the desiccant material from becoming plug-ged by conta~inant~.
: 30 Electrical contact ia mate with the cathode disc 60 by 8 co~ductlve coil compression sprlng 72 whlch has the end convolution thereof closely en-circling the in~ulating di~c 64 and in eng~gement with the surfsce of the cathode ,,. . , .- ~ ~
.
lOS~S~ti, di~c 60 ln opposet relatlon to the fabrlc ring 70 and the ab30rbent materl~l or deslccant m~terlal 68 ~o that the coll ~prlng wlll be pooltloned ~ith the con-volutlons thereof ~psced fro~ the rod or eloctrode 38 throughout the length thereof. The oth~r ent of the ~prlng 18 engaged with the ond of tho bodg 28 dlopo~ct ineerlorly of the branch 24 of the coupllng 26. Thu~, the spring 72 ~erves as a cathode or electrlcal connoctor between the body 28 ant the cathode tl~c 60 and i9 lnsulated fro~ and spaced from the electrote 38. The spr~ng 6erves to maintain a constant compreasive force or pressure a8ainst the dlsc 60 thereby oaintainlog flrm electrlcal contact between the di3c 60 and body 2B in order to be certaln to tran~it even fl~ll conductivity changes of the silica gel. The nut 58 1B pro~ided for clamping engagement of the 811ica gel between the discs 60 and 62 and after ad~ustment has been mate, the threaded ent 56 of the rod 54 ~ay be rivetet over thus locking the nut 58 1Q posltlon.
~ Flgs. 5 and 6 of the drawings illustrate a ~odlfied form of the - lnvention in whl~h a~ alternate structure 18 employed. The adapter 44 illus-trated in Figs. 2 ~nd 3 is rem~ved and a senslng ~le~ent 120 18 attached dlroctly to the externall~ threadet ent portlon 39 of the electrode 38. Thls arran8ement provite~ for a reductlon ln lQngth of the aosembly 80 that the sensing element 18 orlented adJacent the portlon of the plpe coupllng 26 havlng the branch 24 therein. The structure of the probe externally of the coupling 26 18 the sdme as that ln Plgs. 2-4 and the same reference nu~eral~ are employed ; to de~i8nate these st N ctural feaeures.
:~ The senfilng ele~ent in ~lgs. 5 ~ud 6 includes a bod~ 122 having an internally threaded bore 124 which is threated onto the threated end 39 of the electrode 38. The body 122 18 provided with a shoulder 126 and an extenting rod 128 havlng an e~ternally threaded end portion 130. A cathode dlsc 132 i8 s ~ountcd on the rod 128 in ln~ulated relatlon fro~ the rod 128 by an i~sulating sleeve 134 and lnsulated fro~ the flsnge or shoulder 126 by en inaulating disc 136. An ~node di~c 138 1B ~ounted on the rod 128 in opposet spaced relatlon to the cathote tisc 132. Conflnet bet~een the dlscs 132 snd 138 1~ desiccant ~aterlal 140 and a retalning rlng 142 of porous fabrlc ~aterial. The struc-ture of the di~cs 132 and 138 and the deslccant ~nterlal and retaini~g ring , ~05~S9~
thercfor are ~ubstantially the ~ame as the corrosponding Atructure lllustrated in Figs. 2-5.
For applylng pressuro to th~ tlsc 138, a ~ut 144 i~ threaded onto the threaded end 130 of the anote rot 128. A locknut 146 18 appll~t to the threaded e~d 130 externally of the nut 144 wleh the locknut and correspontlng e~d of the ; threadet end 130 belng ground off to substantlally a sh llow conlcal conflgura-tlon as lllustrated ln Flg. 6 after the lock~ut 146 ha8 been ti~htened.
Originally, the locknut would be substantially the same polygo~al shape and configuratlon as the nut 144 and after the nut 144 ha6 been tightened, the locknut 146 i8 tightened after which the locknut and the threaded end 130 are ground to the shape and cou~lguratlon illustrated ~n Fig. 6.
The cla~ping of the tesiccant 68 or 140 between the two discs wlth subst~tlal pressure is slgnificant inasmuch as the pressure crushes the desic-cant ~aterial to sub~tantially a powder for~. The fabrlc retain~ng ring also functions to hold the deslcc3nt in place during the initiel application of pressure and, of course, retains the loose powter resulting from assembly. In actu~l prac~ice, most of the powder will stay in positlon without the retainer , ring although the retainer rin8 of porous fabric dces signiflcantly reduce the plugging of the te~icCAnt ~aterial tue to the absorption of co~taminant material from the refrigerant. The ~pring 72 serves to assure tra~6mittal of current i from disc 60 or 132 to the boty or screw-threaded plug 28 and to compensate for any probe depth atJustment. Continuous sub~tantial pressure is erted on the desiccant by the cLamp nut and locknut asse~bly and for practical applica-tion of the cha~ge in conductivity, an ~plifylng circuit is e~ployed for controlling the refrigeration system.
While the tevice has been illustrated in association wlth a T coupling, it is pointed out that lt may be associated with any type of plpe coupling or inserted into flo~ lines or flow paths of various conflgurations. For example, the assembly could be incorporated into a Y-strainer and can be a~ociated with the flow path by using absorbent materials by which moisture or moisture related contamlnants could be transmlttet to the dssiccant material by capillary action or tbe like. Other materials could be employed to retain the desiccant i ~''':' ''' . :
5f~j mAte~lal in po~ltion as long as they are flexlble, porou~ ant nonconductlve.
The sensing dev~ce, when ln~talled, will requlre only standard plpe fittings, bushings, reduclng ~leeves, nipples, coupllngs and the like. Also, while the ~ensing device has been illustrated ln an elementary refrigeratlon circuit in Fi8. 1 illustrating only one probe point, ln more sophl~tlcated refrigerant circuits, such as pre~ently u~ed hot gas reheat, hot gas tefrost, reverse cycle,llquid ln~ection motor compressor cooling ~ystems and the like, the probe may be located at various locations, amplifier clrcuiting or the like may be employed ant the se~slng device or devices as~ociated with the refrigerating 0 8y8t~m in such a manner to properly protect the sy~te~- The senoing device is operative in assoclatlon with refrlgerant liquids, cold liquid~, cold gas and other phases of refr1~eration ~y8tem8.
One example of a typical installatlo~ 18 the incorporation of a con-ventional relay clrcuit to shut down the entire system wlth probe locations belng ~elected for each individual installation depending upon the installation requirements of each system.
It ls of ~lg~if~cance in this i~vention thst the sensing tevice not only wlll sense the presence of undls~olved moi~ture but also detect abnormal dissolved contamlnants thus detecting potential trouble before it ~tarts and ! 20 providing an audio-visual or mechanical corrective reaction. While fluorinated hydrocarbon refri8erant~ are ma~ufactured under certain ~tandards of moisture csntent, the ability to absorb and hold moisture vsries with the temperature.
It ia possible that moisture content above the evaporator saturation may occur in the refrigerant from normal operatlon, g~sket, evaporator and condenser tube leaks, etc., with such moisture totally absorbed in the liquid refrigerant by high temperature and released in the evaporator and carried through the com-pression cycle ~nt then re-absorbed i~ the compression and condensing cycle, - whlch contition generates acids and water related contaminants. In order to s detect small quantities of moisture snd contaminants which are ab~orbed in the - 30 refrlgorant system thereby avoidlng posslble damage before it occurs, an absorbent has been used that i8 able to pick up moisture ln extremely low concentrations and which changes its electrical chsracteristlcs as a result of the moisture S~i absorptlon. In addition, flrm contact 18 malntalned between the anote, cathode and absorbent mater~al ln order to tranYmlt small conductivlty changes. Thl~
i8 accomplished in the pre~ent lnventlon by employlng dlsc~, initlal adJustment by the lock nut ant fine ~d~ustment o~ the probe depth wlth the entlre unlt belng self-contained ant completing an electrlcal clrcuit through the coll 6pring. Basic ampllfier and relay arrangements ~ay be e~ployed tepenting upon the in~tallation requirements and the devlce may be used to operate proportlonal motor~, modulating control program proportioning swltches or any other deslred control apparatus. By calibratlng a standard ohm~eter ln a humidity ~cale, direct humldity readings can be achleved by inserting into tucts or the llke in order to maintain control of the humltity conditlons thereln.
.
. . .
The present invention generally relate4 to moisture sensing devices and more particularly a sensing device for use in refrigeration systems for detecting the presence of moisture or moisture related contaminants in the refrigera-tion system to enable corrective action to be taken prior to the occurence of damage to the system.
One of the major problems occurring in refrigeration systems is damage caused by moisture or water in the refrig-eration system. Frequently, water, and water-related con-taminants such as acids in the refrigerant liquid, gas, or oil will cause damage to various components of the refrigera-tion system and has been the cause of many major repairs.
This problem has been recognized and some efforts have been made to detect contaminants in the refrigeration system. U,S.
f Patent No. 3,288,960 issued November 29, 1966 to E. J. Miller discloses electrical contacts in the flow path of a fluid to provide a warning or rendèr the system lnoperative when the quality or characteristics of the fluid in the flow path has changed. Other patents disclose electrical circuits in which absorbent members are associated with electrodes to control an electrical circuit in response to moisture absorbed by the absorbent, U.S. Patent No. 3,671,912 issued ~une 20, 1972 to L. S. LaSota discloses an exemplary arrangement of this type. However, such prior devices perform after contact with undissolved contaminants such as moisture to dissolve a soluble material, acid to attach the twisted wires or water in insul-ating oil and do not solve the problem of detecting small ~ quantities or concentrations of moisture and contaminants that - may become absorbed in a refrigerant system which is necessary 29 in order to sense a condition before it causes damage.
mb/~
.''. ~
:', ' ' , ' ' ' ~ ' ' . ' ' ` .
:
, . .
105~S~3~
, The present invention relates to a sensing devlce for detecting the presence of low concentrations of moisture and moisture related contaminants in refrigerant systems comprising an anode and cathode disposed in spaced relation in the flow path of the refrigerant system and adapted to be connected into an electrical circuit, absorbent means disposed between the anode and cathode and in the flow path with the absorbent means including material capable of change of electrical conductivity in response to moisture absorption including dissolved and undissolved moisture and moisture related contaminants in the refrigerant system whereby changes of conductivity will enable electrical flow in the circuit for enabling detectlon o the presence of moisture or moisture related contaminants in the refrigerant system, the anode and cathode being in the form of spaced plates spaced from each other by desiccant material, means maintaining contact pressure between the plates and desiccant material thereby maintaining electrical contact with changes in electrical conductivity of the desiccant material being proportional to absorption of moisture or moisture related contaminants from the refrigerant system.
Figure 1 is a schematic illustration of a refrigeration system with the sensing device of the present invention incorporated therein.
Figure 2 is an elevational view of the sensing device installed in a flow line of the refrigeration system.
Figure 3 is a longitudinal, sectional view, on an enlarged scale, taken substantially upon a plane passing along section line 3-3 of Pig. 2 illustrating the specific structural details of the probe, anode, cathode, absorbent material, retainer and related structure.
Figure 4 is a transverse, sectional view taken sub-stantially upon a plane passin~ along section line 4~4 of Fig.
3 illustrating further structural details of the absorbent ~ - 2 -C dap/t;h, ,, .
- ~os~59~
material and retainer therefor.
Flgure 5 is a sectional view similar to Fig. 2 illustrating another embodiment of the sen~ing device.
Figure 6 is a sectional view illustrating the specific details of the embodiment of the device illustrated in Fi~. S.
Figure 1 illustrates schematically a standard refrigeration system including a compressor 10, water-cooled condenser 12, liquid refrigerant, dryer :, '7 , - 2a -dap/,c~
., , , - . ` ~ , ~
5~ti 14, expansion tevlce 16 and evaporator assombly 18 whlch 1~ shown as the type for chllllng or cooling water or other llquid heat exchang~ medlum. The pro-portlonal sensing devlce of the present invention i8 generally te~lgnated by the numeral 20 and i8 illuatrated in the llquld r~friger~nt llne between the receiver-dryer and expansion dqvlce. However, a~ set forth in more tetall hereinafter, the senslng devlce may have many locatlon~ d~pending upon the particular refrigeration system lnvolved. A~ lllustra~ed, the ~ensing tevice may be lncorporated into the refrigera~t flow path 22 by insertio~ into the branch 24 of a stantart T coupl~ng 26.
The sen~lng device 20 ehow~ in Fig~. 2-4 lnclutes a screw-threaded body 28 that i8 externally thrested a~t i~ tetachably engaged with the inter-nally threatet branch 24 of the coupling 26. The boty 28 lnclutes a polygonal wrench receiving area 30 to facllltate installation of the devlce. A cathode wire 32 is connected to the boty 28 by a seandart screw-type connection 34 80 that the wire 32 19 electrically connectet to the boty 28 which i8 of conductive material. The cathode ~ire 32 may be connected to any portlon of a totally grountet refrigeration system wlth the connection to body 28 only being neces-sary when the probe assembly 20 18 screwed into nonconducting material.
Dlsposet longitudinally through the body 28 which is provided with a - 20 cylintrlcal internsl bore is an insulati~ng ~leeve 26 of porcelaln, plastic or other sultable insulating materlal with the ends of the sleeve 36 extending both lnwardly of the body 28 and outwardly thereof. Extending longltudinally through the in~ulating sleeve 36 is a contuctor rod or electrode 38 which extend~ beyond each e~d of the insulating sleeve 36. The outer end of the electrode 1~ CDnnectet to an electric~l conductor 40 by a stantard screw-type c connection 42 thus electricslly connecting the conductor 40 to the electrode 38 with the inner end of the electrode tending beyond the inner end of the insulating sleeve 36. Thus, the conductors 32 and 40 are insulated from each other and the conductive boty 28 is insulated from the conductive rod or ` 30 electrode 38.
- The rod 38 i8 provided with a threaded end 39 which recelves an adapter 44 having internal threaded bores 46 formed therein. The outer bore 46 1.(~5~59~
threadedly rece~ves an externally thre6ded rod 48 whlch ensbleo ~arlstlon ln the length Qf the probe or tepth o~ the probe by threading the rod 48 lnto and out of the threatet bore 46. A lock nut 50 is psovidet on the threadet rot 48 to lock it i~ sd~ustet posltion.
The threaded rod 48 lncludes a perlpheral boss or ~houlder 52 thereon snd an axlally extending rod 54 pro~ecti~g therefro~ ln oppo~ite relation to the threaded rod 48. The free end of the rod 54 i3 externally threaded at 56 for receiving a pressure ad~usting and retaining nut 58. Positionet between the shoulder 52 and the nut 58 is a cathode disc 60 snd 8n anote disc 62 wlth the anode dl3c 62 restlng against the nut 58 and placed dlrectly on the threaded rod 54. The cathode tisc 6Q la spaced froM the shoulder 52 ~y an in~ulating disc 64 a~d insulated and spaced from the threadod rot 54 by a~ ln3ulating sleeve 66 whlch may be integral wlth or ~eparate from the di~c 64 And constructed of plast$c or other insulating ~aterial.
Interposed bet~een the cathode disc 60 and the anode di~c 62 is a layer of desiccant materlal 68 which i8 ~oisture absorbent and may be in particu-late form ~uch a~ granules or crystals of silica gel, or flilic~ gel ln pellet or powder form or any other hygroscopic materlal that changes it~ electrical characterlstics with the absorption of moisture. The desiccant material 68 is reta~ned ln place between the discs 60 and 62 by a fabric ring or gro~met 70 which ha~ a cross-~ectional area generally equal to the ~pace between the disc~ 60 ~nd 62 and forms an an~ular poroua clo~ure for the ~pace bet~een the discs 60 and 62 thereby retaining the desiccant material within the annular space definet by the tiscs 60 and 62 ant by the external ~urface of the rod 54 and the in~ernal surface of the an~ular fabric ring 70. The an~ular fabric ring 70 i8 of a porous fabric matersl which enables moi~ture or moi~ture con-ta~lnants to be absorbed by the desiccant materlal 68. The ~abric ring 70 also serYes as a ~trainer to prevent the desiccant material from becoming plug-ged by conta~inant~.
: 30 Electrical contact ia mate with the cathode disc 60 by 8 co~ductlve coil compression sprlng 72 whlch has the end convolution thereof closely en-circling the in~ulating di~c 64 and in eng~gement with the surfsce of the cathode ,,. . , .- ~ ~
.
lOS~S~ti, di~c 60 ln opposet relatlon to the fabrlc ring 70 and the ab30rbent materl~l or deslccant m~terlal 68 ~o that the coll ~prlng wlll be pooltloned ~ith the con-volutlons thereof ~psced fro~ the rod or eloctrode 38 throughout the length thereof. The oth~r ent of the ~prlng 18 engaged with the ond of tho bodg 28 dlopo~ct ineerlorly of the branch 24 of the coupllng 26. Thu~, the spring 72 ~erves as a cathode or electrlcal connoctor between the body 28 ant the cathode tl~c 60 and i9 lnsulated fro~ and spaced from the electrote 38. The spr~ng 6erves to maintain a constant compreasive force or pressure a8ainst the dlsc 60 thereby oaintainlog flrm electrlcal contact between the di3c 60 and body 2B in order to be certaln to tran~it even fl~ll conductivity changes of the silica gel. The nut 58 1B pro~ided for clamping engagement of the 811ica gel between the discs 60 and 62 and after ad~ustment has been mate, the threaded ent 56 of the rod 54 ~ay be rivetet over thus locking the nut 58 1Q posltlon.
~ Flgs. 5 and 6 of the drawings illustrate a ~odlfied form of the - lnvention in whl~h a~ alternate structure 18 employed. The adapter 44 illus-trated in Figs. 2 ~nd 3 is rem~ved and a senslng ~le~ent 120 18 attached dlroctly to the externall~ threadet ent portlon 39 of the electrode 38. Thls arran8ement provite~ for a reductlon ln lQngth of the aosembly 80 that the sensing element 18 orlented adJacent the portlon of the plpe coupllng 26 havlng the branch 24 therein. The structure of the probe externally of the coupling 26 18 the sdme as that ln Plgs. 2-4 and the same reference nu~eral~ are employed ; to de~i8nate these st N ctural feaeures.
:~ The senfilng ele~ent in ~lgs. 5 ~ud 6 includes a bod~ 122 having an internally threaded bore 124 which is threated onto the threated end 39 of the electrode 38. The body 122 18 provided with a shoulder 126 and an extenting rod 128 havlng an e~ternally threaded end portion 130. A cathode dlsc 132 i8 s ~ountcd on the rod 128 in ln~ulated relatlon fro~ the rod 128 by an i~sulating sleeve 134 and lnsulated fro~ the flsnge or shoulder 126 by en inaulating disc 136. An ~node di~c 138 1B ~ounted on the rod 128 in opposet spaced relatlon to the cathote tisc 132. Conflnet bet~een the dlscs 132 snd 138 1~ desiccant ~aterlal 140 and a retalning rlng 142 of porous fabrlc ~aterial. The struc-ture of the di~cs 132 and 138 and the deslccant ~nterlal and retaini~g ring , ~05~S9~
thercfor are ~ubstantially the ~ame as the corrosponding Atructure lllustrated in Figs. 2-5.
For applylng pressuro to th~ tlsc 138, a ~ut 144 i~ threaded onto the threaded end 130 of the anote rot 128. A locknut 146 18 appll~t to the threaded e~d 130 externally of the nut 144 wleh the locknut and correspontlng e~d of the ; threadet end 130 belng ground off to substantlally a sh llow conlcal conflgura-tlon as lllustrated ln Flg. 6 after the lock~ut 146 ha8 been ti~htened.
Originally, the locknut would be substantially the same polygo~al shape and configuratlon as the nut 144 and after the nut 144 ha6 been tightened, the locknut 146 i8 tightened after which the locknut and the threaded end 130 are ground to the shape and cou~lguratlon illustrated ~n Fig. 6.
The cla~ping of the tesiccant 68 or 140 between the two discs wlth subst~tlal pressure is slgnificant inasmuch as the pressure crushes the desic-cant ~aterial to sub~tantially a powder for~. The fabrlc retain~ng ring also functions to hold the deslcc3nt in place during the initiel application of pressure and, of course, retains the loose powter resulting from assembly. In actu~l prac~ice, most of the powder will stay in positlon without the retainer , ring although the retainer rin8 of porous fabric dces signiflcantly reduce the plugging of the te~icCAnt ~aterial tue to the absorption of co~taminant material from the refrigerant. The ~pring 72 serves to assure tra~6mittal of current i from disc 60 or 132 to the boty or screw-threaded plug 28 and to compensate for any probe depth atJustment. Continuous sub~tantial pressure is erted on the desiccant by the cLamp nut and locknut asse~bly and for practical applica-tion of the cha~ge in conductivity, an ~plifylng circuit is e~ployed for controlling the refrigeration system.
While the tevice has been illustrated in association wlth a T coupling, it is pointed out that lt may be associated with any type of plpe coupling or inserted into flo~ lines or flow paths of various conflgurations. For example, the assembly could be incorporated into a Y-strainer and can be a~ociated with the flow path by using absorbent materials by which moisture or moisture related contamlnants could be transmlttet to the dssiccant material by capillary action or tbe like. Other materials could be employed to retain the desiccant i ~''':' ''' . :
5f~j mAte~lal in po~ltion as long as they are flexlble, porou~ ant nonconductlve.
The sensing dev~ce, when ln~talled, will requlre only standard plpe fittings, bushings, reduclng ~leeves, nipples, coupllngs and the like. Also, while the ~ensing device has been illustrated ln an elementary refrigeratlon circuit in Fi8. 1 illustrating only one probe point, ln more sophl~tlcated refrigerant circuits, such as pre~ently u~ed hot gas reheat, hot gas tefrost, reverse cycle,llquid ln~ection motor compressor cooling ~ystems and the like, the probe may be located at various locations, amplifier clrcuiting or the like may be employed ant the se~slng device or devices as~ociated with the refrigerating 0 8y8t~m in such a manner to properly protect the sy~te~- The senoing device is operative in assoclatlon with refrlgerant liquids, cold liquid~, cold gas and other phases of refr1~eration ~y8tem8.
One example of a typical installatlo~ 18 the incorporation of a con-ventional relay clrcuit to shut down the entire system wlth probe locations belng ~elected for each individual installation depending upon the installation requirements of each system.
It ls of ~lg~if~cance in this i~vention thst the sensing tevice not only wlll sense the presence of undls~olved moi~ture but also detect abnormal dissolved contamlnants thus detecting potential trouble before it ~tarts and ! 20 providing an audio-visual or mechanical corrective reaction. While fluorinated hydrocarbon refri8erant~ are ma~ufactured under certain ~tandards of moisture csntent, the ability to absorb and hold moisture vsries with the temperature.
It ia possible that moisture content above the evaporator saturation may occur in the refrigerant from normal operatlon, g~sket, evaporator and condenser tube leaks, etc., with such moisture totally absorbed in the liquid refrigerant by high temperature and released in the evaporator and carried through the com-pression cycle ~nt then re-absorbed i~ the compression and condensing cycle, - whlch contition generates acids and water related contaminants. In order to s detect small quantities of moisture snd contaminants which are ab~orbed in the - 30 refrlgorant system thereby avoidlng posslble damage before it occurs, an absorbent has been used that i8 able to pick up moisture ln extremely low concentrations and which changes its electrical chsracteristlcs as a result of the moisture S~i absorptlon. In addition, flrm contact 18 malntalned between the anote, cathode and absorbent mater~al ln order to tranYmlt small conductivlty changes. Thl~
i8 accomplished in the pre~ent lnventlon by employlng dlsc~, initlal adJustment by the lock nut ant fine ~d~ustment o~ the probe depth wlth the entlre unlt belng self-contained ant completing an electrlcal clrcuit through the coll 6pring. Basic ampllfier and relay arrangements ~ay be e~ployed tepenting upon the in~tallation requirements and the devlce may be used to operate proportlonal motor~, modulating control program proportioning swltches or any other deslred control apparatus. By calibratlng a standard ohm~eter ln a humidity ~cale, direct humldity readings can be achleved by inserting into tucts or the llke in order to maintain control of the humltity conditlons thereln.
.
. . .
Claims (9)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A sensing device for detecting the presence of low concentrations of moisture and moisture related contaminants in refrigerant systems comprising an anode and cathode disposed in spaced relation in the flow path of the refrigerant system and adapted to be connected into an electrical circuit, absorbent means disposed between the anode and cathode and in the flow path with the absorbent means comprising material capable of change of electrical conductivity in response to moisture absorption including dissolved and undissolved moisture and moisture related contaminants in the refrigerant system whereby changes of conductivity will enable electrical flow in the circuit for enabling detection of the presence of moisture or moisture related contaminants in the refrigerant system, said anode and cathode being in the form of spaced plates spaced from each other by desiccant material, means maintaining contact pressure between the plates and desiccant material thereby maintaining electrical contact with changes in electrical conductivity of the desiccant material being proportional to absorption of moisture or moisture related contaminants from the refrigerant system.
2. The structure as defined in claim 1 wherein said desiccant material is in particulate form, and porous means disposed peripherally of the desiccant material to retain it between said plates.
3. The structure as defined in claim 1 wherein said desiccant material includes silica gel in particulate form, and a porous fabric annular member disposed between and engaged by said plates, said annular member being disposed outwardly of the desiccant material to retain it between the plates while enabling contact between the desiccant material and ambient conditions in the flow path.
4. The structure as defined in claim 1 wherein said anode and cathode plates are in the form of discs insulated from each other, an annular retaining member encircling the desiccant material at the outer periphery of the discs for retaining the material between the discs, said retaining member being in the form of a porous fabric ring to enable transmission of moisture to the desiccant material.
5. The structure as defined in claim 4 wherein said anode and cathode discs are carried at the inner end of a probe including an insulating sleeve, an inner electrode connected to the anode and an outer conductive body operatively associated with the cathode for completing the electrical circuit to the cathode, and spring means including a metallic coil spring in contact with and between the body and cathode for completing the circuit therebetween.
6. The structure as defined in claim 5 wherein the length of the electrode may be varied thereby varying the position of the anode with variation in such position being compensated for by the spring thereby enabling adjustment of the position of the anode and cathode.
7. A device for detecting the presence of foreign material in a region subject to contamination by such material comprising a pair of spaced conductive members disposed in said region and adapted to be operatively connected to an electrical circuit, and absorbent means disposed between said members and controlling electrical conductivity therebetween, said absorbent means being in the form of desiccant material capable of absorbing the foreign material and changing its electrical conductivity proportional to the quantity of foreign material absorbed for indicating proportionately the presence of foreign material, said conductive members being in the form of plates, means, for moving the plates toward each other for pressure contact with the desiccant material, and means supporting said plates in said region, said desiccant material being in particulate form, and a flexible porous member encircling the desiccant material between the plates for confining the material, said means for moving the plates towards each other including a conductive spring means engaged between one of said plates and the electrical circuit, and means engaging the other of said plates to enable adjustment of contact pressure of the plates against the desiccant material.
8. The structure as defined in claim 7 wherein said plates are in the form of circular discs, said flexible porous member being in the form of a fabric ring having an external diameter generally equal to the external diameter of the plates to form a seal between the plates for retaining the desiccant material but enabling passage of the foreign material to the desiccant material, said means engaging the other of said plates to enable adjustment of contact pressure including a screw-threaded rod and nut assembly with the rod being connected to the electrical circuit and insulated from the conductive spring means and the plate engaged by the conductive spring means.
9. A device for detecting the presence of moisture in a refrigeration system comprising an anode and cathode adapted to be connected to an electrical circuit and being disposed in spaced relation to each other and disposed in a flow path in the refrigeration system with the refrigerant in the flow path defining an ambient region for the anode and cathode, particulate moisture absorbent material disposed between and in contact with the anode and cathode, said absorbent material being capable of change in electrical conductivity proportional to its ambient moisture conditions thereby defining a reversible variable resistor changing its electrical resistance proportionately to its ambient moisture conditions, and a porous flexible member disposed peripherally of the absorbent material and extending between the anode and cathode to retain the absorbent material between the anode and cathode and moisture sensing communication between the absorbent material and the ambient moisture conditions in the flow path.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA206,149A CA1059596A (en) | 1974-08-01 | 1974-08-01 | Proportioning moisture sensing device for refrigeration systems |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA206,149A CA1059596A (en) | 1974-08-01 | 1974-08-01 | Proportioning moisture sensing device for refrigeration systems |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1059596A true CA1059596A (en) | 1979-07-31 |
Family
ID=4100819
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA206,149A Expired CA1059596A (en) | 1974-08-01 | 1974-08-01 | Proportioning moisture sensing device for refrigeration systems |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1059596A (en) |
-
1974
- 1974-08-01 CA CA206,149A patent/CA1059596A/en not_active Expired
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