Abstract:
A valve manifold for use with a pressure sensing apparatus such as a differential pressure transmitter, the manifold being characterized by a simplified passageway system internally of the manifold and by reduced size relative to prior art manifolds, the manifold having valve chambers defining valve seats, each of the valve seats being located within a referenced prison defined by mounting holes having axes which are generally perpendicular to first and second, parallel faces of the manifold.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to valve manifolds used with pressure sensing devices, particularly with a pressure transmitter. 
     Pressure transmitters serve the purpose of monitoring variables of a process fluid flow in a pipeline. A pressure transmitter has a first and a second process fluid inlet. In operation, each of the two inlets communicates, with a separate point in a process fluid pipeline. The pressure transmitter typically transmits pressure values or differentials at the two points. The transmitted values are then used in extrapolating various conditions prevailing in the pipeline. One example of an operative arrangement of a pressure transmitter is shown in U.S. Pat. No. 4,466,290 (Frick) issued Aug. 21, 1984 and in other prior art referred to hereafter. 
     In pipeline systems, there is often a limited space around a pressure transmitter. Different spacing between the centers of process fluid source outlets at the pressure transmitter has to be accommodated with a minimum points of potential leaks. For this reason, pressure transmitters have lately been mounted directly on a valve manifold. Valve manifolds of this type are solid blocks provided with a number, usually three or five, valves. The valves control the passage through the block from a process or cleaning fluid source to the transmitter and/or to a vent discharge. The block is interposed between the pressure transmitter and the process fluid source. 
     The limited space available around a pressure transmitter resulted in attempts to reduce the size of the manifold such that the manifold and the valves mounted in the manifold require as little space as possible while allowing safe and convenient manual operation of the valves in manipulating the flow of process or cleaning fluid through the manifold. 
     Our U.S. Pat. No. 5,277,224, issued Jan. 11, 1994 (Hutton et al.) which is incorporated herein by reference, presents an example of a manifold where the space required for the operation of the manifold is reduced. However, viewed from the standpoint of the present invention, there is still a part of the manifold which projects sidewise beyond the a periphery defined by mounting holes which typically are adapted to register with mounting holes or bolts of an associated pressure transmitter. 
     Examples of further prior art references showing the state of the art include, for instance, U.S. Pat. No. 3,596,680 (Adams), issued Aug. 3, 1971; U.S. Pat. No. 3,756,274 (Wolfgramm), issued Sep. 4, 1973. U.S. Pat. No. 1,797,591 (Sartakoff) issued Mar. 24, 1931 and other references. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to further advance the art of manifolds for the purpose described and to provide a manifold which would allow safe operation of a multiple valve manifold, where the space required for operation of the valves is further reduced and where the overall arrangement of passageways within the manifold block is simplified to reduce production costs. 
     In general terms and referring to one aspect of the present invention, a valve manifold is provided for use with a pressure sensing apparatus. The manifold comprises an integral body including a parallel and generally planar first and second face section; and a peripheral section extending between the first and second face sections. There is provided a process fluid inlet port means in said second face section and a process fluid outlet port means in said first face section. The latter is complementary with process inlet ports of an associated pressure sensing apparatus. 
     A plurality of apparatus mounting holes are disposed about the periphery of the first face section. The mounting holes are compatible with bolts for fixedly securing the associated pressure sensing apparatus to said first face section of the manifold. The axes of said mounting holes are generally perpendicular to the first face section. 
     There are at least three valve mounting bores each machined in said peripheral section. As is known, each valve mounting bore includes a threaded outer portion at the peripheral section of the block, and a coaxial, generally cylindric valve chamber. Each valve chamber terminates at its end remote from the threaded outer portion by a valve seat. The valve seat forms an end of a first associated passageway disposed inside the body or block. 
     Each valve chamber further communicates, via a communication port in a side wall of the chamber, with a second associated passage disposed inside the body or block. 
     In accordance with one aspect of the invention, the seats of all the valves of said plurality of valves are located within the reference prism defined by the axes of the mounting holes. This feature provides the advantage of a substantial reduction of the space required for actuation stems of the valves at the side of the manifold block. 
     Another feature of the present invention is utilized when the manifold is of the type including vent outlet or outlets for the purpose of cleaning or flushing the passageways. In such arrangement, the process fluid inlet ports and vent outlet port or ports are both in the second face of the block. This provides the advantage that no space is required to the side of the block for any conduit connections as all ports required for the function of the manifold are disposed generally perpendicularly to the faces of the manifold block. 
     In most practical applications, there are two process fluid inlet ports and two vent ports where the flushing fluid leaves the system. Preferably, these ports are arranged in the second face such that the pair of the process ports is disposed on a line parallel with and spaced from another line on which the two vent ports are located. Another advantageous arrangement of the two pairs of ports is in that the pairs of process and vent ports are on axes which cross each other generally at the center of the second face of the manifold block. 
    
    
     The invention will be described by way of two preferred exemplary embodiments, with reference to the accompanying simplified, diagrammatic, not-to-scale drawings. The drawings show: 
     FIG. 1 a top and front perspective view showing a first embodiment of the manifold block including the invention; 
     FIG. 2 a bottom and rear perspective view of the manifold block of FIG. 1; 
     FIG. 3 a top view of the manifold according to FIG. 1; 
     FIG. 4 a front view thereof; 
     FIG. 5 a bottom view thereof; 
     FIG. 6 section VI--VI of FIG. 4; 
     FIG. 7 section VII--VII of FIG. 4; 
     FIG. 8 section VIII--VIII of FIG. 4; 
     FIG. 9 section IX--IX of FIG. 5; 
     FIG. 10 section X--X of FIG. 5; 
     FIG. 11 section XI--XI of FIG. 5; 
     FIG. 12 a top and front perspective view showing a second embodiment of the manifold block including the invention; 
     FIG. 13 a bottom and rear perspective view of the manifold block of FIG. 12; 
     FIG. 14 a top plan view of the manifold shown in FIG. 12; 
     FIG. 15 a front view thereof; 
     FIG. 16 a bottom plan view thereof 
     FIG. 17 section XVII--XVII of FIG. 15 
     FIG. 18 section XVIII--XVIII of FIG. 15 
     FIG. 19 section XIX--XIX of FIG. 16 
     FIG. 20 section XX--XX of FIG. 16 
     FIG. 21 (on the sheet of FIG. 17) the right hand side view of the representation of FIG. 15, the left hand side view thereof being identical; 
     FIG. 22 an enlarged partial view on section line XXII--XXII of FIG. 4 but showing vent valves installed in the block; and 
     FIG. 23 an enlarged partial view on section line VI--VI of FIG. 4 but showing an equalizer valve installed in the block. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring firstly to the embodiment shown in FIGS. 1-11 , The manifold has a body of the type of a solid block 120 made--in the embodiment shown--from stainless steel, it being understood that the choice of material is optional and depends on a particular application. The block has the shape of a rectangular prism and includes opposed top and bottom walls or first and second face sections 121, 122, a first side wall 123, a second side wall 124 a front wall 125 and a rear wall 126. The walls 123-126 enclose the periphery of the block 120 and are generally referred to as &#34;a peripheral section.&#34; 
     Machined in the second face section 122 is a process fluid first inlet port 127 and a process fluid second inlet port 128. The first inlet 127 communicates, via an upwardly and inwardly inclined first process passage 129 (FIG. 10) with a short horizontal branch 130 which defines a coaxial, inwards directed extension of a first block valve chamber 131 co-axial with a threaded first block valve opening 132. The threaded opening 132 in effect forms a threaded outer portion of a block valve mounting bore comprised of the valve chamber 131 and the opening 132. Each valve chamber of the block defines a valve seat as will be described. 
     The remaining valve mounting bores described throughout this specification have the same functional arrangement. 
     The second inlet port 128 likewise communicates, via an upwardly and inwardly inclined second process passage 133 with a short horizontal branch 134 which defines a coaxial, inwards directed extension of a valve chamber 135 co-axial with a second block valve bore opening 136. 
     The transition between the horizontal branch 130 at its inlet into the valve chamber 131 defines a valve seat co-operating with a valve member (not shown) for selectively blocking the entrance of pressurized process fluid into the valve chamber 131. Similarly, the transition between the branch 134 at its inlet into the valve chamber 135 defines a valve seat co-operating with a valve member (not shown) for selectively blocking the entrance of second pressurized process fluid into the valve chamber 135. 
     The valve chamber 131 permanently communicates through a short first radial conduit 137 with a first instrument cavity 138. Similarly, the valve chamber 135 communicates via a short second radial conduit 139 with a second instrument cavity 140. 
     The cavity 138 is also in permanent communication with an inlet of an oblique conduit 141 which slopes in the direction from the top wall toward the bottom wall 122 and obliquely toward the second side wall 124, as best seen from FIG. 10. The outlet of the conduit 141, in turn, permanently communicates with a coaxial extension conduit 142 of the equalizer valve chamber 143 which, in turn, is coaxial with the threaded outer part 144 of the equalizer valve bore. The cavity 140 permanently communicates, through a vertical conduit 150 and an oblique conduit 145, with the equalizer valve chamber 143. 
     The general structure of the equalizer valve chamber 143 is similar to what has been described above. That is to say, the transition between the valve chamber 143 and the extension conduit 142 defines a valve seat for a valve member of a valve (not shown) normally threadably secured at the bore 144. It will be thus appreciated that with the equalizer valve open, the valve chamber 143 FIG. 6 and the extension conduit 142, and thus the two cavities 138, 140, are in a fluid communication to equalize the pressure in the cavities 138, 140. 
     The cavity 138 further communicates, through an oblique conduit 146 which slopes from the top wall 121 to the bottom wall 122 and obliquely in the direction toward the rear wall 126 (FIG. 8), with an extension conduit 147 coaxial with a cylindric first vent valve chamber 148 which, in turn, is coaxial with a threaded valve bore 149 of a first vent valve. 
     As mentioned above, the conduit 150 connects the cavity 140 with the oblique conduit 145 and thus with the equalizer valve chamber 143. FIG. 7 shows that the lower portion of the vertical conduit 150 also connects the cavity 140 with a short extension conduit 151 forming a coaxial extension of a cylindric second vent valve chamber 152 which, in turn, is coaxial with a threaded part 153 of the valve mounting bore 153-152 of a second vent valve. 
     Despite certain structural differences to be discussed later, The vent valve chambers 148 and 152 and their extension conduits 147, 151 are arranged similar to the remaining valve chambers in that there is a valve seat at the inlet of each extension conduit 147, 151 into its associated valve chamber 148, 152. The seat is compatible with a closing member the structure of which will be described later. 
     The end of the first vent valve chamber 148 remote from the associated first valve threaded bore 149 communicates with an inlet port of a transverse conduit 154 FIG. 11. As best seen from FIG. 5, the inlet port of the conduit 154 is located in the side wall of the valve chamber 148, near the valve seat of the chamber 148. The downstream end of the transverse conduit 154 is in a permanent communication with a first vent outlet 155 (FIG. 11). The end of the shorter, second vent valve chamber 152 near its valve seat is similarly in a permanent communication with an inlet port (FIG. 9) of a second transverse conduit 156 and through it with a second vent outlet 157. 
     The vent outlets 155, 157 are adapted to become connected to a suitable discharge conduits exterior to the body of the manifold and not forming a part of the invention. 
     There are two threaded bores 158, 159 in the rear wall 126. They serve the purpose of securing the body 120 to a bracket. Furthermore, four mounting holes 160-163 are provided for bolts securing a complementary pressure transmitter to the top face 121 of the body 120, in a sealing engagement with the cavities 138, 140. 
     One of the features of the present invention is seen from FIGS. 3, 5 and 6. In particular, apart from the relatively small thickness as measured between the upper and lower faces 121, 122, those figures show that there are four mounting holes 160-163 disposed about the periphery of the block 120. The axes of the holes 160-163 are perpendicular to the first face section 121. Also, it can be appreciated that the axes of the holes 160-163 coincide with sides of a reference prism. In the embodiment shown, the reference prism is a four-sided prism where the axes actually define each a joinder or corner between two adjacent sides. The number of the mounting holes is optional and is usually given by the disposition of mounting holes on a flange of a pressure transmitter or the like instrument to be used with the block 120. However, even if the number of the mounting holes is more than as shown, the arrangement is such that at least some of the axes of the mounting holes define corners of the reference prism. 
     Both embodiments of the block described show a block for a five valve manifold. There are provisions made for mounting two block valves, one equalizer valve and two vent valves. Those skilled in the art will readily appreciate, however, that the features of the present invention can be applied in a three valve embodiment which typically has only two block valves and an equalizer valve. 
     It is true that the advantages of the compactness of the design of the block of the present invention are best appreciated in a five valve manifold. Yet, it can be said that there are &#34;at least three&#34; valve mounting openings, namely the threaded bores 132 and 136 for two block valves for selectively blocking the passage of the process fluid and one equalizing valve mounting bore 144. Note that the inner end of the valve chambers associated with the mounting bores mentioned, namely valve chambers 131, 135 and the equalizer valve chamber 143 are all disposed with their inner ends (where the respective valve seats are located) located inside the imaginary prismatic surface. Of course, in a five valve manifold, the remaining two valve chambers 148, 152 meet the same criteria as the &#34;at least three&#34; chambers 131,135, 143 with respect to their location relative to the mounting bores 160-163. 
     The drawings further show that the same compact size can be achieved, according to the invention, for a five valve manifold, where at least one, and preferably two, valve chambers 148, 152 and mounting bores are of a reduced diameter compared with chambers 131, 135, 143 but are relatively long to accommodate the type of a valve, where the valve seal is located on the valve stem and engages not the bonnet of the valve, but the interior of the valve chamber itself. This allows the use of an axially reduced length of the bonnet which, combined with a hexagonal head at the outer end of the valve stem, provides space saving feature whereby two valves can be located one to each side of another valve, in the exemplary embodiment, to each side of an equalizer valve. It is preferred that the valves in which the seal is inside the valve chamber and the stem has a hexagonal head for engagement by a wrench or the like, be vent valves. The hexagonal heads provide an additional safety feature as with the distinct appearance they virtually eliminate the possibility of inadvertent opening of the two valves instead of one of the remaining three valves. 
     Yet another feature seen from the drawings of the first embodiment is in that there is provided a five valve compact manifold wherein both the process fluid inlet and the vent outlet or outlets are arranged in the same face 122 of the body. This provides further reduction of the space required in comparison with existing five valve manifold, where the vent outlets usually have to be directed sideways and thus require additional space at the side of an installed manifold, for connection to vent pipes. 
     Despite the extremely small overall area of the face 122 of the block, there is sufficient spacing provided between the process fluid inlets and the vent outlets to allow the use of standard couplings for sealed connection. This is due to the fact that the use of one long and one short valve chamber 148, 152 disposed to both sides of but at a different level from the equalizer valve, permit the connection by short, easily machined passageways 154, 156 to vent outlet ports placed on an axis generally central to the block and perpendicular to the axis on which the process fluid inlet ports 127, 128 are located. 
     Another noteworthy feature of the manifold block shown in FIGS. 1-11 but also in FIGS. 12 to 20 is in that all passageways are comprised of straight passageway sections. These sections are all straight and are either perpendicular to the faces of the block or, if they are inclined, they are still parallel with at least one of the planar outer walls of the block. An example of such inclined passageway section is the oblique conduit 145 which is at an acute angle to the axis of the equalizer valve chamber 143 but is parallel with the top face 121. This is contrary to known multiple-valve manifolds where the valves are disposed on at least two distinct planes parallel with the top face, where a number of so called compound angle passages (i.e. passages which are obliquely inclined with respect to any of the six basic surface walls 121-126). The machining of compound angle passages presents a complex and thus expensive and time consuming task in producing the block. Their elimination is mainly facilitated by the use of the vent valve chambers 148, 152 (and also 248, 253) having a specifically designed length which depends upon the location of the vent valve ports 155, 157 relative to the process inlet ports 127, 128 (and also 255 and 255 vis-a-vis 227, 228 as described hereafter with reference to FIGS. 12, 13. The same applies to all other oblique or inclined passageway sections, for instance 129, 133, 146, 154, 156 and their counterparts 229, 235, 244 of the second embodiment which will now be described in greater detail. 
     Reference may now be had to FIGS. 12-20 which show the second embodiment of the manifold block according to the invention. In many respects, the second embodiment includes features similar to those described with reference to FIGS. 1-11, as witnessed, for instance, by the comments in the preceding paragraph. 
     As in the first embodiment, there is provided a solid, preferably, but not exclusively, stainless steel rectangular prism shaped block 220. As in the preceding embodiments, the block has top and bottom wall 221, 222, a first side wall 223, a second side wall 224 a front wall 225 and a rear wall 226. 
     FIG. 16, shows first and second inlet ports 227, 228 machined in the bottom wall 222, for the process fluid. The inlet 227 communicates, via an upwardly and inwardly inclined first passage 229 with an extension 230 of a first block valve chamber 231 co-axial with a threaded first block valve bore 232. The valve chamber 231, in turn, communicates via a short connecting conduit 233 with a first instrument cavity 234. The second inlet 228 communicates in the same fashion, via second passage 235, extension 236 and valve chamber 237, coaxial with threaded bore 238 of the second block valve, and then via a short, vertical connecting conduit 239 with the second instrument cavity 240. 
     The first instrument cavity 234 further communicates via a first short, vertical equalizer channel 241 with a horizontal-oblique channel 242 (FIG. 17) the discharge end of which connects with an equalizer valve chamber 243. Similarly, the second instrument cavity 240 communicates via a downwardly and inwardly sloping channel 244 the outlet of which merges with an inward end of an equalizer valve extension channel 245 (FIGS. 17, 20) coaxial with the equalizer valve chamber 243. 
     Each of the circular cavities 234, 240 is connected to the respective vent conduit. The cavity 234 connects via a vertical conduit 246 (FIG. 14) with a horizontal extension line 247 (FIGS. 18, 19) coaxial and in communication with a first vent valve chamber 248 which, in turn, connects through a short vertical line 249 with a threaded vent discharge port 250. In an identical fashion, the cavity 240 connects via a conduit 251 (FIGS. 14, 17), a horizontal extension 252 coaxial with second vent valve chamber 253, the chamber 253 and a short vertical line 254 (FIGS. 18, 19) with a threaded vent port 255. Note that the length of the vent valve chambers 248, 253 is the same, but is greater than that of any of the remaining valve chambers 232, 237 and 243. This is to facilitate the orientation of the passageway sections 249, 254 which can be machined perpendicular to the second face 222 and straight into the vent discharge ports 250, 255 (FIG. 19). 
     As in the preceding embodiments, the threaded bores 256, 257 (FIG. 17) serve the purpose of securing the block 220 to a suitable support bracket or the like (not shown) and the four mounting holes 258-261 serve the purpose of accommodating bolts which hold a pressure transmitter in sealing engagement with the top surface 221 and thus with the cavities 234, 240. 
     Note that in the second embodiment the valve chambers 248, 253 of the vent valve mounting bores are of an even length. This feature accommodates the second preferred embodiment where the pairs of process fluid inlet ports 227, 228 and of the vent outlets 250, 255 are each on a separate reference line parallel with the other reference line, as opposed to the crossing arrangement of the reference lines in the first embodiment. 
     Referring now to FIG. 22, as mentioned above, the enlarged representation generally corresponds to a partial of on view on line XXII--XXII of FIG. 4. Referring to the structure of the block itself, there is shown a pair of vent valves 301, 302 installed in the first embodiment of the manifold block of the invention. 
     The long vent valve chamber 148, and the associated coaxial threaded bore 149 and the transverse conduit 154 and the extension conduit 147 are as shown in FIG. 5. Threaded in the thread of the first vent valve bore 149 is a bonnet 303 having a wrench compatible outer hexagonal portion 304. The bonnet 303 has a coaxial threaded bore 305 which is threadably engaged by a threaded portion of a vent valve stem 306. The inner part of the stem 306, marked with reference number 307, is freely movable within the valve chamber 148. It is provided, at a point near the bonnet 303, with a seal mounting groove within which is disposed a pair of backup rings 308, 309 from Teflon and with an intermediately positioned sealing 0-ring 310 made from a suitable elastomeric material. 
     The end of the stem 307 carries a hemispherical tip 311 compatible with a valve seat 311. Thus, the tip 310 co-operates with the valve seat 311 to selectively block or open the passage of fluid from extension conduit 147 to the transverse conduit 154 and from there to the first vent outlet 155. 
     The opposite, outer end of the stem 307 has fixedly secured to it a hexagonal head compatible with a suitable wrench. Accordingly the vent valve can only be open or closed by using a suitable tool. 
     The valve mounted in the second vent valve mounting bore comprised (FIG. 7) of the threaded second vent valve bore 153 and the coaxial second vent valve chamber 152 communicating with the short extension conduit 151 and with the transverse conduit 156 (FIG. 11) which terminates at the second vent outlet 157. 
     The overall arrangement of the second vent valve 302 is the same as that of the first vent valve described above except for the length of the inner part 307a of the valve stem 306a. Therefore, the parts of the second vent valve 302 and the associated second valve mounting bore are not described in detail. 
     FIG. 22 shows the valves 301,302 in an open state. Using a suitable wrench, the stem 306 can be turned to cause, an axial displacement of the stem 306 toward the seat 312 until the tip 311 sealingly engages the seat 312 to interrupt the flow of the fluid from extension line 147 to the transverse conduit 154. 
     The operation of the manifolds described is a typical operation of a five-valve manifold which is known per se and therefore does not have to be described. It will suffice to briefly mention that under normal circumstances, when a pressure differential is to be sensed at the pressure transmitter or the like pressure processing apparatus, blocking valves mounted in the mounting bores 132, 136 or 232, 238 are open allowing communication between the process inlet ports and the cavities. If absolute pressure is to be sensed, one of the block valves is closed. If pressure is to be made equal at both sides of a diaphragm of the sensing apparatus, the equalization valve is open. And the vent valves are open whenever one or both cavities at the instrument are to be relieved of pressure. 
     Reference should now be had to the arrangement shown in FIG. 23. While the drawings of the present specification are not to scale, an effort has been made to show the true relative size of the components shown in FIG. 23. 
     The manifold block is the same as that of FIG. 23, as indicated by reference number 125 designating the front wall of the block. As described, the equalizer valve mounting bore comprises the valve chamber 143 (FIG. 6) and a threaded bore 144 at the front wall 125. The valve chamber 143 communicates, via an opening at the valve seat 320 with the extension conduit 142 and, via an opening in the side wall of the valve chamber 143 with the oblique conduit 145. 
     The threaded bore 144 threadably receives a bonnet 321 of an equalizer valve referred to with reference number 322. The equalizer valve 322 and thus the equalizer valve mounting bore 144, 143 are of the type typically used in valve manifold of this type. That is to say, the valve 322 is of the type wherein a valve stem 323 is threadably received in the bonnet 321. The bonnet has an outer thread 325 mounted in the threaded bore 144, as is well known in the art. 
     The bonnet defines a packing chamber which receives a packing 326 held in place and compressed by a packing gland 327 threaded in the outer end of the packing chamber and locked in its position by a locking nut 328. The inside and axially outer portion of the gland 327 is threaded by a thread compatible with that on the outside of the stem 323. A dust cap 329 protects the threaded connection between the stem 323 and the gland 327. The inner end of the stem 323 is provided with a hemispherical closing member 330 compatible with the seat 320 so that the operation of the valve 322 by the handle 331 results in selective closing or opening of the fluid flow from the extension conduit 142, through the valve chamber 143 and into the oblique conduit. 
     The valve 322 is one of many commercially available valves of the type with the packing inside the bonnet. it can be readily appreciated that the valve 322 requires substantially more space at the exterior of the manifold (i.e. at the vicinity of the front wall 125) both as to the overall maximum length as a distance from the wall 125, and as regards the overall diameter. The vent valve 301 or 302, on the other hand, requires a much shorter outer length and a smaller diameter, not to mention that the selectively designed length of the valve chamber 148 or 152 can be utilized in simplifying the structure of the conduits of the manifold by bringing the respective valve seat and the outlet port to a position where the connecting conduits do not require to be at a complex angle of a double oblique inclination relative to the surface of the block. 
     Those skilled in the art will appreciate that further embodiments exist which differ from those described, without departing from the scope of the present invention as set forth in the accompanying claims. For instance, as one of many variants, while the five valve arrangement is preferred, it is not beyond the scope of the present invention to provide an arrangement where only one vent valve mounting hole (and thus only one vent valve) would be provided. Another readily conceivable variant is that where, in some installations, the structure of the vent valve utilized in the preferred embodiments, could be utilized for another type of valve or valves. 
     I therefore wish to protect by letters patent which may issue on the present application all such embodiments as fairly fall within the scope of my contribution to the art.