Abstract:
A pressure/vacuum generator is established by coupling the pressure port of a vacuum generator to an air pressure source while coupling a valve in fluid communication with the exhaust port of the vacuum generator. When the valve is in a normally open condition (i.e, the exhaust vented to atmosphere), the vacuum port of the pressure/vacuum generator generates a vacuum. When the valve is closed, thereby closing off the exhaust port, the vacuum port becomes a pressure port. Thus, this pressure/vacuum generator can be used in any number of fluid (liquid and gas) systems (e.g., fluid recovery system, fluid transfer system, etc.)that require both a pressure source and a vacuum source while using a minimum number of components.

Description:
FIELD OF THE INVENTION 
     The invention pertains to the field of fluid systems, and more particularly, to systems that require the use of both a pressure source and a vacuum source. 
     BACKGROUND OF INVENTION 
     In many fluid systems, there is a need to have both a pressure source (e.g., a pump) as well as a vacuum source (e.g., vacuum pump, vacuum generator, etc.). For example, in fluid recovery systems or fluid transfer systems, there is a need to collect a fluid from a first location (e.g., a main fluid system, a first fluid system, a fluid collection point) and move the fluid into a reservoir and then to evacuate the fluid from that reservoir either back to the main fluid system (i.e., a recovery system) or to a second fluid system (i.e., a transfer system). To accomplish this, a vacuum source draws the fluid into the reservoir and then a pressure source drives it out of the reservoir. 
     The following U.S. patents are various types of fluid systems using pressure sources and vacuum sources. 
     U.S. Pat. No. 2,400,651 (Marsh) discloses a liquid elevating system. A summary of the Marsh system  2  is shown in FIG.  1 . The Marsh system  2  uses a shuttle valve  4  between an air supply  6 , a reservoir  8  and a pressure inlet (P) of a vacuum generator  10 , as well as an air-operated valve  12  between the reservoir  8  and a vacuum inlet (V) of the vacuum generator  10 . A reservoir inlet check valve  16  and a reservoir outlet check valve  14  are also used. A float mechanism  20  inside the reservoir  8  controls the shuttle valve  4 . 
     U.S. Pat. No. 2,522,077 (Wahl) discloses a tank truck. A summary of the pumping system  34  used in the Wahl truck is shown in FIG.  2 . The pumping system  34  uses a pump (P, driven by a motor  36 ) to draw a vacuum on a reservoir  38  to pull liquid in, and a mechanical screw  40  coupled to another motor  42  to pump it out. Manually-operated input  44  and output  46  valves are also used, as well as an air inlet check valve  48 . The system  34  is manually-operated. 
     U.S. Pat. No. 2,664,911 (Thompson) discloses a portable vacuum and pressure liquid tank truck. A summary of the pumping system  18  of the truck is shown in FIG.  3 . The pumping system  18  uses a pump  20  (driven by a motor, M) to draw a vacuum or pressurize a reservoir  22 ; a separator  24  with a float valve  26  keeps fluid from getting into the pump  20 . The pump  20  action (vacuum, or pressure) is based on the position of a valve  28  that is manually controlled. Manually-operated input  30  and output  32  valves are also used. 
     U.S. Pat. No. 3,315,611 (Thompson) discloses a portable vacuum and pressure liquid tank truck, and uses a pumping system similar to the pumping system disclosed in U.S. Pat. No. 2,664,911 (Thompson) but adds an air bleeder to the system. The bleeder line draws air into the tank along with the liquid during the vacuum stage, thus eliminating foam. During the pressure stage, pressurized air is mixed with the liquid in the tank, making it easier to pump. 
     U.S. Pat. No. 4,770,610 (Breckner) discloses a frail material slurry pump system  50 . A summary of the Breckner system  50  is shown in FIG.  4 . This system  50  uses a vacuum pump  52  (driven by a motor M) and combination valving (V P1 -V P3 , V V1 -V V3 ,BV I  and BV O ) to pull a vacuum on a reservoir  56  and uses a compressor (not shown, but forms a part of the air supply) with the combination valving (V P1 -V P3 , V V1 -V V3 , BV I  and BV O ) to pressurize the reservoir  56 . The BV I  and BV O  valves are a bladder type to prevent damage to the frail material being pumped. This combination valving (V P1 -V P3  with V V1 -V V3 ) controls the inlet BV I  and outlet BV O  bladder valves of the reservoir  56 . 
     U.S. Pat. No. 4,828,461 (Laempe) discloses an apparatus for metering flowable materials in sand core making machines. A summary of the pumping system  58  used therein is shown in FIG.  5 . The pumping system  58  works in a similar manner to the Marsh system  2  (FIG. 1) but includes two shut-off valves,  60  and  62 , going into a vacuum generator  64 , whereby the shut-off valve  60  is coupled to the pressure port (P) of the vacuum generator  64  and the shut-off valve  62  is coupled to the vacuum port (V) of the vacuum generator  64 . In order to pressurize a reservoir  66 , the pumping system  58  uses a third shutoff valve  68  (for dividing the air supply, while closing the upper shut-off valve  60 ). Reservoir inlet  70  and outlet  72  check valves are also used with the reservoir  66 . 
     U.S. Pat. No. 5,451,144 (French) discloses an air-operated pump system  76 . A summary of this pump system  76  is shown in FIG.  6 . The system  76  primarily uses gravity to draw liquid in, whereby a vaccum (V) is available as an option to assist gravity. The system  76  utilizes two sources of air pressure: a main air supply  78  and an auxiliary air supply  80 , the latter of which is fed to a reservoir  84  via flow restrictor  82 . Two poppet valves  86  and  88  are used. An air-operated three-way valve  90  is controlled by the poppet valves  86  and  88 . A quick-exhaust valve  92  is coupled between the three-way valve  90  and the reservoir  84 . Inlet  94  and outlet  96  check valves are also used with the reservoir  84 . 
     However, none of these references teach or suggest controlling the exhaust port of a vacuum generator for creating both a pressure source and a vacuum source. 
     OBJECTS OF THE INVENTION 
     Accordingly, it is the general object of this invention to provide an invention that overcomes the disadvantages of the prior art. 
     It is an object of the present invention to provide an apparatus, and a method for an apparatus, that can act as both a pressure source and a vacuum source. 
     It is an object of the present invention to provide an apparatus, and a method for an apparatus, that can act as both a pressure source and a vacuum source while utilizing a minimum number of components. 
     It is still yet a further object of the present invention to provide any liquid or gas system/method with an apparatus, and a method for an apparatus, that can act as both a pressure source and a vacuum source. 
     It is yet another object of the present invention to provide fluid recovery/transfer systems that utilize a minimum number of components. 
     It is still yet a further object of the present invention to provide fluid recovery/transfer systems that are less prone to problems. 
     SUMMARY OF THE INVENTION 
     These and other objects of the instant invention are achieved by providing, in a system requiring both a pressure source and a vacuum source, an improvement comprising: (a) a lumen (e.g., a Venturi tube) for conveying an air stream from an upstream port of the lumen toward a downstream port of the lumen wherein the lumen includes an orifice in the surface of the lumen located between the upstream port and the downstream port and wherein the upstream port is coupled to an air pressure source (e.g., 70-150 psi air supply); (b) a valve coupled in fluid communication with the downstream port for opening and closing off the downstream port; and (c) the orifice pulling a vacuum whenever the valve is open and the orifice generating a positive pressure whenever the valve is closed. 
     These and other objects of the instant invention are also achieved by providing, in a system for recovering or transferring fluid from a first location to a second location, an improvement comprising: (a) a lumen (e.g., a Venturi tube) for conveying an air stream from an upstream port of the lumen toward a downstream port of the lumen wherein the lumen includes an orifice in the surface of the lumen located between the upstream port and the downstream port and wherein the upstream port is coupled to an air pressure source (e.g., 70-150 psi air supply); (b) a valve coupled in fluid communication with the downstream port for opening and closing off the downstream port; (c) a reservoir having a first port coupled in fluid communication to the orifice; and (d) wherein the orifice pulls a vacuum in the reservoir for drawing fluid from the first location through a second reservoir port whenever the valve is open and wherein the orifice pressurizes the reservoir to evacuate the fluid therein to the second location through a third reservoir port whenever the valve is closed. 
     These and other objects of the instant invention are also achieved by providing an automatic fluid recovery system for recovering fluid from a main fluid system having at least one escape point (e.g., a leak point, a collection point for accumulating fluid, etc.) and returning the escaping fluid to the main system. The fluid recovery system comprises: (a) a reservoir for collecting the escaping fluid and having a plurality of ports; (b) a first valve coupled in fluid communication between a first port of the reservoir and the at least one escape point; (c) a lumen (e.g., a Venturi tube) for conveying an air stream from an upstream port of the lumen toward a downstream port of the lumen wherein the lumen includes an orifice in the surface of the lumen located between the upstream port and the downstream port and wherein the upstream port is coupled to an air pressure source (e.g., 70-150 psi air supply); (d) a second valve coupled in fluid communication to the downstream port of the lumen; (e) controller means electrically coupled to the first valve and to the second valve; (f) means responsive to the level of the fluid collected in the reservoir and electrically coupled to the controller means for providing electrical signals indicative of the level of the fluid in the reservoir to the controller means; and (g) wherein the controller means controls the activation of the first valve and the second valve, based on the electrical signals, to fill the reservoir and then to evacuate the reservoir and wherein the evacuated fluid is returned to the main fluid system via a check valve coupled in fluid communication with a third port of the reservoir. These and other objects of the instant invention are also achieved by providing a automatic fluid transfer system for transferring fluid from at least one source fluid system having a predictable (e.g., predetermined, constant, etc.) flow to a destination fluid system. The fluid transfer system comprises: (a) a reservoir for receiving fluid from the at least one source fluid system and having a plurality of ports; (b) a first valve coupled in fluid communication between a first port of the reservoir and the at least one source fluid system; (c) a lumen (e.g., a Venturi tube) for conveying an air stream from an upstream port of the lumen toward a downstream port of the lumen wherein the lumen includes an orifice in the surface of the lumen located between the upstream port and the downstream port and wherein the upstream port is coupled to an air pressure source (e.g., 70-150 psi air supply); (d) a second valve coupled in fluid communication to the downstream port of the lumen; (e) controller means electrically coupled to the first valve and to the second valve; and (f) wherein the controller means controls the activation of the first valve and second valve to collect fluid from the at least one source fluid system into the reservoir and then to evacuate the reservoir, whereby the evacuated fluid is transferred to the destination fluid system via a check valve coupled in fluid communication with a third port of the reservoir. 
     These and other objects of the instant invention are also achieved by providing a method for establishing a pressure source and a vacuum source. The method comprises the steps of: (a) providing an air pressure source (e.g., 70-150 psi air supply) that delivers an air stream; (b) coupling a lumen (e.g., a Venturi tube) to the air pressure source whereby the lumen conveys the air stream from an upstream port of the lumen toward a downstream port of the lumen and wherein the lumen includes an orifice in the surface of the lumen located between the upstream port and the downstream port; (c) coupling a valve in fluid communication with the downstream port for opening and closing off the downstream port; (d) opening the valve to create a vacuum source at the orifice; and (e) closing the valve to create a pressure source at the orifice. 
     These and other objects of the instant invention are also achieved by providing a method for recovering or transferring fluid from a first location to a second location. The method comprises the steps of: (a) providing an air pressure source (e.g., 70-150 psi air supply) that delivers an air stream; (b) coupling a lumen (e.g., a Venturi tube) to the air pressure source whereby the lumen conveys the air stream from an upstream port of the lumen toward a downstream port of the lumen and wherein the lumen includes an orifice in the surface of the lumen located between the upstream port and the downstream port; (c) coupling a valve in fluid communication with the downstream port for opening and closing off the downstream port; (d) coupling a first port of a reservoir in fluid communication with the orifice; (e) opening the valve to draw fluid from the first location into the reservoir through a second reservoir port; and (f) closing the valve to evacuate the fluid in the reservoir to the second location through a third reservoir port. 
     These and other objects of the present invention are also achieved by providing a method for recovering escaping fluid (e.g., leaking fluid, accumulating fluid, etc.) from at least one escape point (e.g., a leak point, a collection point where accumulating fluid gathers) in a main fluid system and returning the escaping fluid thereto. The method comprises the steps of: (a) providing an air pressure source (e.g., 70-150 psi air supply) that delivers an air stream; (b) coupling a lumen (e.g., a Venturi tube) to the air pressure source whereby the lumen conveys the air stream from an upstream port of the lumen toward a downstream port of the lumen and wherein the lumen includes an orifice in the surface of the lumen located between the upstream port and the downstream port; (c) coupling a first valve in fluid communication with the downstream port for opening and closing off the downstream port; (d) coupling a first port of a reservoir in fluid communication with the orifice; (e) coupling a second port of the reservoir in fluid communication with a second valve that is in fluid communication with the at least one escape point; and (f) controlling the operation of the first valve and the second valve to collect escaping fluid in the reservoir through the second port and then to return the collected fluid to the main fluid system through a third reservoir port. 
     These and other objects of the present invention are also achieved by providing a method for transferring fluid from at least one source fluid system having a predictable flow to a destination fluid system. The method comprises the steps of: (a) providing an air pressure source (e.g., 70-150 psi air supply) that delivers an air stream; (b) coupling a lumen (e.g., a Venturi tube) to the air pressure source whereby the lumen conveys the air stream from an upstream port of the lumen toward a downstream port of the lumen and wherein the lumen includes an orifice in the surface of the lumen located between the upstream port and the downstream port; (c) coupling a first valve in fluid communication with the downstream port for opening and closing off the downstream port; (d) coupling a first port of a reservoir in fluid communication with the orifice; (e) coupling a second port of the reservoir in fluid communication with a second valve that is in fluid communication with the at least one source fluid system; and (f) controlling the operation of the first valve and the second valve to collect fluid from the at least one source fluid system into the reservoir through the second port and then to transfer the collected fluid to the destination fluid system through a third reservoir port. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: 
     FIG. 1 is a summary of a prior art pumping system, namely U.S. Pat. No. 2,400,651 (Marsh); 
     FIG. 2 is a summary of another prior art pumping system, namely U.S. Pat. No. 2,522,077 (Wahl); 
     FIG. 3 is a summary of another prior art pumping system, namely U.S. Pat. No. 2,664,911 (Thompson); 
     FIG. 4 is a summary of another prior art pumping system, namely U.S. Pat. No. 4,770,610 (Breckner); 
     FIG. 5 is a summary of another prior art pumping system, namely U.S. Pat. No. 4,828,461 (Laempe); 
     FIG. 6 is a summary of another prior art pumping system, namely U.S. Pat. No. 5,451,144 (French); 
     FIG. 7 is a block diagram of the present invention; 
     FIG. 8 is a functional diagram of the present invention with the exhaust port being in an open condition; 
     FIG. 9 is a functional diagram of the present invention with the exhaust port in a closed condition; 
     FIG. 10 is a block diagram of a first exemplary application of the present invention, known as a fluid recovery system (FRS); and 
     FIG. 11 is a block diagram of a second exemplary application of the present invention, known as a fluid transfer system (FTS). 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now in detail to the various figures of the drawing wherein like reference characters refer to like parts, there is shown at  100  in FIG. 7 a pressure/vacuum generator, which is assigned to Bijur Lubricating Corporation of Bennington, Vt. 
     The pressure/vacuum generator  100  comprises an air pressure source  102  (e.g., 70-150 psi air supply), a vacuum generator  104  (e.g., Bijur Part No. 27296) and a valve  106  (Bijur Part No. 27299). The air pressure source  102  is coupled to the pressure port (P) of the vacuum generator  104  and the valve  106  is coupled to the exhaust port (E) of the vacuum generator  104 . The valve  106  acts to either permit the exhaust port to be open to the atmosphere or to be closed to the atmosphere. FIGS. 8 and 9 are functional diagrams of the vacuum generator  104  with the valve  106  open (FIG. 8) and with the valve  106  closed (FIG.  9 ). As can be seen in FIGS. 8 and 9, the vacuum generator  104  basically comprises a Venturi tube  108 ; the vacuum port V comprises a small orifice  109  located just right of the center of the Venturi tube  108 . When the valve  106  is open and the air pressure source  102  is coupled to the pressure port (P) of the vacuum generator  104 , the air stream  105  creates a vacuum at the vacuum port V in accordance with the Bernoulli principle. However, when the valve  106  is closed, thereby blocking the exhaust port (E), the air stream  105  is forced through the small orifice  109 , thereby generating a positive pressure at the vacuum port V. None of the prior art teaches or suggests the control of the vacuum generator&#39;s  104  exhaust to establish both a pressure source and a vacuum source. 
     An exemplary application of the pressure/vacuum generator is shown in FIG. 10 which depicts a fluid recovery system (hereinafter “FRS”)  200 . The FRS  200  is used as part of a main fluid system. The main fluid system (e.g., a lubrication system) comprises any number of devices that may be prone to leaks, including tubing, connectors, elbows, flanges, bearings, seals, gaskets, etc. (all of which are not shown). It is necessary to capture the leaking fluid and return it to the main fluid system. 
     Furthermore, in addition to restoring leaking fluid to a main fluid system, the FRS  200  also restores accumulated fluid back to the main fluid system. For example, the main fluid system in a punch press machine may intentionally overlubricate the slides/ways of the machine. As a result, an accumulation of that lubricant occurs at an accumulation point or a collection point (e.g., a collection tray). The FRS  200 , being coupled to the accumulation/collection point, also restores the accumulated fluid back to the main fluid system. Thus, it is within the broadest scope of the FRS  200  that the term “escape”, “escaping”, etc. as used throughout this application covers both leaking fluid (i.e., unintentional egress of fluid from the main fluid system) and accumulating fluid (i.e., intentional egress of fluid, at an accumulation point or a collection point, from the main fluid system) which cannot otherwise re-enter the main fluid system without the FRS  200 . 
     The escaping fluid is captured in a conduit, lumen, collection tray, etc. (indicated by reference number  208 ) that is connected to, or around, these escape points (not shown). This conduit  208  is in fluid connection with the inlet to the FRS  200 . In particular, the conduit  208  is coupled to a vacuum valve  210  (e.g., Bijur Part Nos. 27300/27310). The vacuum valve  210  has an outlet coupled to a reservoir  212  (e.g., Bijur Part No. 27275). At a resevoir part  292  the reservoir  212  comprises a means  214  responsive to the level of the fluid being collected in the reservoir  212 ; an example of such a means is an ultrasonic level detector (not shown), or any other type of level detection that provides a signal responsive to the level. In one embodiment, a liquid dual-level switch (e.g., Bijur Part No. 27301, 24 volts DC switch, 0.5 amps max ) is used. The liquid dual-level switch comprises an upper switch  211 , a lower switch  213  and a magnetic float  215 ; when the reservoir  212  is empty, the magnetic float  215  and the lower switch  213  are electromagnetically coupled, and the lower switch  213  outputs an “empty” signal; when the reservoir  212  is full, the magnetic float  215  and the upper switch  211  are electromagnetically coupled, and the upper switch  211  outputs a “full” signal. The reservoir  212 , at another reservoir port  291  is also in fluid communication with the vacuum port (V) of the vacuum generator  104 . The reservoir  212 , at another port  293  is also in fluid communication with an outlet check valve  216  (e.g., Bijur Part No. 27302). The outlet check valve  216  is in fluid communication with the main fluid system. A programmable logic controller (PLC)  218  (e.g., IDEC Micro-1 PLC, Type FC1A4E, Base  24  manufactured by IDEC Izumi Corp. of Japan, or any properly configured logic device, e.g., a microprocessor, a microcontroller, etc.) is electrically coupled to the solenoids of the vacuum valve  210  and the valve  106 ), as well as to the means  214  responsive to the level of the fluid being collected (hereinafter the “level means  214 ”) in the reservoir  212 . A drain  220  is provided in the reservoir  212  for maintenance purposes. 
     Operation of the FRS  200  is as follows. To collect escaping fluid from the escape point(s), the PLC  218  de-energizes the valve  106  (thereby opening the valve to permit exhaust) while energizing the vacuum valve  210  (opening the valve  210 ). This action causes a vacuum to be drawn in the reservoir  212 . The result is that escaping fluid from the main fluid system is drawn into the reservoir  212  through the vacuum valve  210 . As fluid is drawn in and when the fluid level causes the magnetic float  215  to be adjacent the upper switch  211 , the liquid dual-level switch outputs the “full” signal to the PLC  218 , thereby causing the PLC  218  to de-energize the vacuum valve  210  (closing the vacuum valve  210 ) while energizing the valve  106 . Energizing the valve  106 , closes off the exhaust port, E, of the vacuum generator  104  which, as discussed above, converts the vacuum port, V, into a pressure port. This action pushes the collected fluid out of the reservoir  212 , through the outlet check valve  216  and back to the main fluid system  205  (or even to a liquid waste container, not shown). As the fluid leaves the reservoir  212 , the magnetic float  215  falls; when the magnetic float  215  is adjacent to the lower switch  213 , the “empty” signal is transmitted to the PLC  218  which then de-energizes the valve  106  and re-energizes the vacuum valve  210 . This cycle is then repeated. 
     It should be understood that a plurality of conduits, lumens, collection points, etc. (indicated by reference number  208 ) from various escape points in the main fluid system, each with a respective vacuum valve  210 , can be coupled to the reservoir  212 ; each vacuum valve  210  is also electrically coupled to the PLC  218 . Thus, the PLC  218  can control each vacuum valve  210  in sequence (e.g., activate one vacuum valve  210  for  10  seconds while keeping all other vacuum valves  210  closed; then shutting off that vacuum valve while opening another vacuum valve  210 , and repeating the cycle). 
     It should also be understood that only a single pressure/vacuum generator  100  and reservoir (e.g., reservoir  212  or  312 ) are required to service a multiplicity of vacuum valves (e.g., vacuum valves  210  or  310 ), as shown in FIGS. 10-11. 
     It should also be understood that the level means  214  in the FRS  200  covers all types of mechanisms that couple the level of the fluid collected in the reservoir  212  to the valve  106  and the vacuum valve  210 . In other words, as shown, the level means  214  provides an electrical signal to the PLC  218  which, in turn, controls the respective solenoids of the valve  106  and the vacuum valve  210  at the appropriate times. However, it is within the broadest scope of the FRS  200  that the level means  214  includes a direct interface with the valve  106  and the vacuum valve  210  so that movement of the level means  214  closes/opens the valve  106  while closing/opening the vacuum valve  210 . 
     Another exemplary application of the pressure/vacuum generator is shown in FIG. 11 which depicts an automatic fluid transfer system (hereinafter “FTS”  300 ). The FTS  300  is similar to the FRS  200 , except that the FTS  300  involves transferring a source fluid from a source fluid system  303 , having a predictable (e.g., predetermined, constant, etc.) flow, to a destination fluid system  305 . Since the flow of the source fluid system  303  is predictable, there is no need to monitor the level of the fluid collecting in the reservoir  312 . As a result, the PLC  318  (or sequential timer, or other timing devices) can operate on a timing basis rather than having to sense the reservoir  312  fluid level. Other than that, the components of the FTS  300  correspond to the components of the FRS  200 , whereby the reference numbers beginning with “3—” are the same for those reference numbers beginning with “2—”. Furthermore, as shown in FIG. 11, the FTS  300  can operate using a plurality of source fluid systems  303  (each having a predictable, e.g., predetermined, constant, etc., flow) for transferring source fluids from each of their respective source fluid systems to the destination fluid system  305 . 
     The important aspect of the pressure/vacuum generator  100  is the automatic valving of the exhaust port, E, of the vacuum generator  104 . Valving the exhaust port permits the use of a single source to act as both the “puller” and “pusher” of a fluid while using only a single valve ( 106 ). This increases the reliability of any system (e.g., the FRS  200 /FTS  300 ) which uses the pressure/vacuum generator  100  by decreasing the number of components that can fail while reducing the cost of the fluid systems&#39; operation. Thus, it should be understood that the present invention  100  has an unlimited number of applications and that the FRS  200  and the FTS  300  discussed above are only by way of example. 
     It should be understood that the term “fluid” used throughout the present application includes both liquids and gases and therefore the pressure/vacuum generator  100 , as well as the FRS  200  and FTS  300 , discussed above, can all be implemented for gas systems also. In addition, the term “automatic” used throughout the present application identifies that there is no manual operation involved in order for the FRS  200  or the FTS  300  to operate. 
     It should also be understood that where the valves depicted in the present application use electric solenoid control, other types of control (e.g., pneumatically-controlled valves) are also covered by the broadest scope of this invention. 
     Without further elaboration, the foregoing will so fully illustrate my invention that others may, by applying current or future knowledge, readily adopt the same for use under various conditions of service.