Oxygen generator

An oxygen generator having a honeycomb body composed of an oxygen ion conducting material is disclosed. The honeycomb body includes one or more air channels, each of which is composed of a plurality of the first channels and the first connecting holes therebetween to form a tortuous air flow path for lengthening the detention time of air, and oxygen collection channels, each of which is composed of a plurality of the second channels and the second connecting holes therebetween for oxygen passage. The first and second channels, which extend laterally through across the body and parallel to each other, are all sealed with glass members at both the front face and back face of the body. The source gas is provided and exhausted from one side face of the body to the other side face via a plurality of air inlets and air outlets, respectively, which laterally intersect the first channels. A power source are with a negative terminal and positive terminal, respectively, connected to the air channels and oxygen collection channels, respectively, to force oxygen ion flow across the oxygen ion conducting material such that gas in oxygen collection channels will become riches in oxygen than in air channels. The oxygen within the oxygen collection channels is collected from the side face of the body through a plurality of oxygen outlets which laterally connect with the second channels.

FIELD OF THE INVENTION

The present invention pertains to an oxygen generator, particularly to an oxygen generator having honeycomb structure body.

DESCRIPTION OF THE PRIOR ART

Currently on the market of the well-known type of the oxygen sensor may be of a potential type, which is made of yttrium partially stabilized zirconium (PSZ) as a solid electrolyte for oxygen ion to conduct therein. While two gases contain with different oxygen partial pressures are injected from the two ends of the foresaid oxygen sensor, zirconia or other ionic conductor, the oxygen ions will diffuse to a side having low O2concentration from the side having high O2concentration through the conductor. In the processes, oxygen molecules enter the zirconia, and then get electrons forming oxygen ions, thereafter, the oxygen ions diffuse to the other face of the ionic conductor losing electrons again and back to oxygen molecules, and then release from the ionic conductor. The diffused mechanism of oxygen ions will generate a potential difference, or called emf, across the two sides of the ionic conductor.

The principle of the oxygen sensor is based on the emf measured between the two opposite surfaces of the ionic conductor while the first gas is a reference air flow and the other is an unknown gas flow. The O2partial pressure of the unknown gases can be acquired according to the Nernst equation. The principle of the oxygen generator is exact opposite to that of the oxygen sensor. For an oxygen generator, an emf is applied to two electrodes of the oxygen generator to provide a driving force for oxygen ions diffused to the anode electrode from the cathode electrode so that the oxygen concentrations at the anode electrode side become high.

A conventional oxygen generator is disclosed by Lawless in U.S. Pat. No. 5,961,929. InFIG. 1, the oxygen generator100is a ceramic honeycomb structure comprising a body102formed of oxygen ion conductive material. A plurality of first channels114and a plurality of second channels116, from a front face118through the body102to a rear face120. Among them, the first channels114and the second channels116, are, respectively, formed at alternately rows. A voltage source122with a negative terminal124and a positive terminal126connected in parallel respectively, to the channels114and116to form the cathode and the anode electrode of the oxygen generator100. In addition, the right face136of the body102has third channels137in lateral connected the second channels116so that the collected oxygen gas will outflow from the third channel137.

The oxygen generator100disclosed by Lawless had done something improvements as comparing with his earlier product. For example, the openings of the second channels116at the front face118and the rear face120has been sealed by sealed members142to make sure the purity of the oxygen gas therein. In addition, the improvement includes the aligned holes154, which are provided that the third channels137are easier to align with the second channels116, as is shown inFIG. 2.

InFIG. 2, it is a perspective view of a portion of the oxygen generator100illustrating one lateral row of the second channel116having the third channel formed at the longitudinal end of sidewalls of the second channels116in a form of the semi-circle openings154. The locations of the semi-circle openings154are near the front face118and beneath the sealed member142. It may remove the problem of the misalignment of the openings154since one can visually examine the third channel137prior to attach the sealed member142so that one can ensure the third channels do not intersect with the first channels.

Nevertheless, the air passage from the entry to the outlet for every first channel114is straight, which is inferior for the oxygen gas conducting to the second channels116although there is an emf to drive it. Thus this inferior need to be improved.

SUMMARY OF THE INVENTION

An object of the present invention is to improve this problem so as to improve the oxygen collecting efficiency.

The present invention disclosed an oxygen generator. it comprises a honeycomb body formed of an oxygen ion conductor having n column by m row channels formed therethrough, wherein among the channels located at the odd rows have a first porous conductive layer coated thereon walls of the first channels to serve as cathode electrodes and the even rows have a second porous conductive layer coated thereon walls of the second channel to serve as anode electrodes and the channels at the same row are electrically in parallel connected. M pairs of glass sealed members corresponding to m rows of channels to seal the outlets. Each pair of which is mount on two rectangular recesses at front and rear side faces of the channels in a row to seal the outlets of the channels. The cathode channels are interconnected via first through-holes, which are alternatively, formed at the front side face or at the rear side face of the channel adjacent wall and beneath rectangular recess or the glass sealed member in a way across the honeycomb body to constitute a tortuous path for air flow. The anode channels are interconnected via second through-holes, which are formed at both front side face and the rear side face of the channel adjacent wall and beneath rectangular recess. M/2 number of inlets of air drilled through a first outmost sidewall of the honeycomb body to intersect with the first column of said channels of said cathode electrodes, respectively. m/2 number of outlets of exhaust air drilled through a second outmost sidewall of said honeycomb body to intersect with the first column of said channels of said cathode electrodes, respectively, wherein said first outmost sidewall are opposite to said second outmost sidewall; and m/2 O2outlets for oxygen collection drilled through said first outmost sidewall of said honeycomb body to connected the first column of said channels of said anode electrodes, respectively.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Reference will now be made in detail to exemplary embodiments, which are illustrated in the accompanying drawings, wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or similar parts.

Referring toFIG. 3, a perspective appearance diagram of an oxygen generator100in accordance with a first preferred embodiment of the present invention is shown. The oxygen generator100includes a honeycomb structure102, with at least one air flow channel and an oxygen flow channel. As shown inFIG. 3, a plurality of the air flow channels or called first channels114and the oxygen flow channels or called second channels116are formed from a front face118through the body102to a rear face120, respectively. The body102is made of the oxygen ion conductive material such as a bismuth oxide (Bi2O3) doubly stabilized with Y2O3and ZrO2.

According to a preferred embodiment, a plurality of first channels114and the second channel116are interlaced in row and arranged as n columns×m rows. The odd rows are the first (air flow) channels114and even rows are the second (oxygen flow) channels116. Every row at the front face118is sealed by using a sealed member142such as a glass sealed slat and the rear face120are sealed by the same144so that all of the inlets and outlets of the first and second channels114,116are closed. Preferably, the two outmost rows of the honeycomb structure are always served as first channel114so that every row of the second channel116is sandwiched by two rows of the first channels114, as shown inFIG. 3. This arrangement has found to get more efficiency on oxygen collections.

To, form the electrodes, all of the walls of the first channels and the second channels114,116are formed with a first porous conductive layer, and a second porous conductive layer thereon, respectively. To electrically connect the channels in each row, an electrical conductive screen113may attach on the sealed member142,144or mounted on the front side face and the rear side face of the walls. In an embodiment, the electrical conductive layer113is an Ag screen so that the first channels114at the same row are electrically in parallel connected. Similarly, the second channels116at the same row are in parallel connected.

The first and the second porous conductive layers1141,1161are formed by a dip-coating method. In the method, slurry having gold power mixed therein is coated on the walls of the first channels114and the second channels116. The slurry is provided as a catalytic for transformation between oxygen molecules and oxygen ions to prompt efficiency. In another embodiment, a Ag/Pd paste is further pasted on the slurry of the second channels116and a Ag paste is pasted on the slurry of the first channel114. The slurry and paste are both porous after drying.

A power source122with its negative terminal124and positive terminal126are connected, respectively, to the first channels114and second channels116of the honeycomb oxygen generator100to provide a driving force for prompting oxygen ions diffusing from the first channels to the second channels.

Referring toFIG. 4A, a right side view of the oxygen generator100illustrating air inlets131drilled through the right face136along a direction perpendicular to the long axis of the first channels114. Each inlet131is connected to a first channel114of the first column nearest to the right face136.

Still referring toFIG. 4A, two outlets of oxygen arranged as a column are drilled through the right face136of the honeycomb body102to connect to the second channels, which are along a direction perpendicular to the long axis of the second channels116.

Referring toFIG. 4B, a left side view of the oxygen generator100illustrating two outlets132of exhaust air arranged as a column are drilled through the left face134along a direction perpendicular to the long axis and connected thereto the first channels114.

The positions of forgoing inlets of air131, O2outlets137, and outlets of exhaust air132are just exemplary and not intended to limit the claimed scope. For instance their positions may all locate at the same side136or partially at the opposite side. However, the air inlets131and O2outlets137are preferably at the same side to acquire better oxygen collection efficiency.

Referring toFIG. 5, it shows a cross-sectional view cut along a line A-A′ ofFIG. 3. Two rectangular recesses1141a,1141bare formed at the front end and the rear end of each channel wall1141by milling the honeycomb body102row by row for housing the sealed members142,144, respectively. The first channels are further interconnected via through-holes1140, which are further formed beneath the rectangular recesses1141aat a front side face1141aof one column and beneath the rectangular recesses1141bat a rear side face1141bof the adjacent column. Please refer toFIG. 6A, a local perspective diagram ofFIG. 3shown one row of the first channels114too.

In a preferred embodiment, the positions of the through-holes1140, are in turn changed between the first end (front side face)1141aand the second end (rear side face)1141ball the way across the honeycomb body102so as to create a tortuous air flow path, shown as arrow direction inFIG. 6Athereby increasing the time of air staying so that the chances of the oxygen ions tunneling the oxygen ion conductor are increase. The through-holes1140may be notches, rectangular cuts, or semi-circles.

Turning back toFIG. 5, the both ends of the second channel walls1161are also formed with two rectangular recesses1142respectively by milling the honeycomb body102row by row for housing the sealed members142,144. The through-holes1160are formed at the both ends of the channel walls1161beneath the rectangular recesses1142for manufacture convenience and for interconnecting the second channels116. The through-holes1160are adjacent and beneath the rectangular recesses1142.

After forming the conductive layers, the Ag screen, the glass sealed members142,144having a size matches the rectangular recesses1142are then mounted thereon. The through-holes1140beneath the glass slats142,144are served as the air passage. Thereafter, a heating step is carried out and held the temperature between about 700˜760° C. for 40 to 60 minutes to soft the glass sealed members142,144for ensuring the outlets of the channels114,116are completely sealed.

In another embodiment the through-holes1140aren't formed at the ends but at a mid section of the sidewall, as shown inFIG. 6B.

In the oxygen generator according to prior art, the air path from the entry to the outlet is straight in comparison with the tortuous flow path of the present invention. Hence the oxygen collection efficiency of the oxygen generator according to the present invention is prompted significantly.

Furthermore, some of the silver silk wool117may disposed in the first channels114to create turbulence flows to further increase the possibility of the oxygen ions diffused through the solid ion conductor, as is shown inFIG. 7.