Patent Publication Number: US-2022225841-A1

Title: Portable hand washing unit

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Patent Application Ser. No. 63/138,898 filed on Jan. 19, 2021. The contents of the aforementioned application are incorporated by reference herein. 
    
    
     TECHNICAL FIELD 
     The present disclosure generally relates to hand washing equipment. More specifically, the present disclosure relates to a portable self-contained hand washing unit having a plurality of separate spaced apart washing stations capable of simultaneously accommodating multiple users. 
     BACKGROUND 
     The importance of frequent hand washing has long been recognized as valuable in order to maintain good personal hygiene and limit the spread of pathogens that may cause diseases. These hand washing units typically include a fresh or clean water supply which is dispensed to a sink for washing and a means for storing or disposing of the waste water. For the comfort of the user and to encourage conformity with best hand washing practices it may be advantageous if the hand washing unit also comprises a means for heating the water supplied to the sink. This may be challenging to achieve at locations such as construction or tourist sites, where access to fixed plumbing and power supplies is limited or unavailable. 
     Additionally, such portable hand washing equipment typically only accommodates a single user at a given time, which is undesirable at locations where large numbers of people congregate, for example sporting events or music concerts. Thus, it would be desirable to provide a hand washing unit that can accommodate multiple users at one time. Furthermore, it would be desirable to allow the multiple users to be spaced apart at the recommended distance specified by health agencies to minimize the spread of pathogens, such as through the air, between the users. 
     SUMMARY 
     The present disclosure provides a portable hand washing unit that may include (a) a base unit; (b) a fresh water tank operable to receive and store a volume of clean water, (c) a waste water tank operable to receive and store a volume of waste water, (d) a plurality of washing stations, each washing station in fluid communication with the fresh water tank and the waste water tank, (e) a water pump in fluid communication with the fresh water tank and the plurality of washing stations; (f) a heating and mixing system in fluid communication with the water pump; and (g) a power source in electrical communication with the water pump and heating and mixing system where: the water pump is operable to disperse clean water from the fresh water tank to the plurality of washing stations; and the heating and mixing system is operable to control the temperature of the clean water dispersed by the water pump to the plurality of the washing 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In drawings which illustrate embodiments, 
         FIGS. 1A and 1B  are right-side and left-side plan views of a hand washing unit in an operational configuration in accordance with one embodiment of the present disclosure. 
         FIGS. 1C and 1D  are front and rear plan views of the hand washing unit of  FIGS. 1A and 1B . 
         FIG. 1E  is a top plan view of the hand washing unit of  FIGS. 1A and 1B . 
         FIGS. 1F and 1G  are top plan and side-cross sectional views of a washing station of the hand washing unit of  FIGS. 1A and 1B . 
         FIGS. 2A and 2B  are right-side and left-side plan views of the hand washing unit of  FIGS. 1A and 1B  in a storage or transport configuration. 
         FIGS. 2C and 2D  are front and rear plan views of the hand washing unit of  FIGS. 2A and 2B . 
         FIG. 3  is partial cross-sectional top plan view of the hand washing unit of  FIGS. 1A and 1B . 
         FIG. 4  is a fluid communication schematic of the hand washing unit according to an embodiment of the present disclosure. 
         FIG. 5  is an electrical communication schematic of the hand washing unit according to an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure is generally directed to a portable hand washing unit. More specifically, the present disclosure provides a portable hand washing unit that is self-contained and can accommodate a plurality of users at one time. Advantageously, the hand washing unit is configured to supply water to a plurality of spaced apart washing stations which enables multiple users to access the unit at one time while maintaining suitable spacing between each user. This may be particularly desirable in situations where social distancing is required, for example in situations where it is desired to reduce the risk of the spread of pathogens between users. 
     The portable hand washing unit of the present disclosure is also configured to be easily transported to and from a location as needed, such as to a movie or television filming location, a construction site, a sporting event, a concert or any other suitable location. Furthermore, because the hand washing unit is self-contained, it may be situated at a remote location, distanced from any utility resources, such as public or private electrical or plumbing resources. In one embodiment, the hand washing unit is a trailer mounted unit and may be towed by a suitable vehicle and unhitched at the desired location. 
     According to an embodiment, the portable hand washing unit may generally include a fresh water tank, a water pump, a heating and mixing system, a plurality of washing stations and a waste water tank. The fresh water tank is configured to receive and store a volume of fresh (or clean) water for supply to the plurality of washing stations. The water pump is operable to pump the clean water stored in the fresh water tank to the heating and mixing system and to the plurality of washing stations. The heating and mixing system is operable to control the temperature of the clean water supplied to each of the washing stations and may include a water heater and a mixing device or mixing valve. The water heater may be powered by an on-board power source or propane gas and internal flame and is operable to supply heat to the clean water to produce heated water. The mixing device or mixing valve is operable to blend clean water dispersed directly from the fresh water tank to the mixing device or valve with heated water dispersed from the water heater in order to supply clean water to each of the washing stations at a pre-determined temperature and for a pre-determined period of time. Thus, the fresh water tank and water heater are in fluid communication with the mixing device or mixing valve which is in turn in fluid communication with each washing station. Each of the washing stations may include a faucet and a non-porous sink. When the faucet is activated by a user, clean water is dispensed to the sink as waste water. Each sink is in fluid communication with the waste water tank. The waste water tank is operable to collect and store the waste water. The waste water (also known as “grey water”) which may include traces of dirt, grease, food, soap, detergent and other contaminants, may be treated by any suitable water treatment method or disposed. 
     The hand washing unit also includes an on-board power source for suppling power to operate the water pump, water heater and any other component of the unit which may require power. In an embodiment the power source is an on-board DC power supply. 
     In one embodiment, the hand washing unit includes at least four washing stations to accommodate at least four users at one time. Each of the washing stations may further include a soap dispenser and a paper towel dispenser. In other embodiments, the hand washing unit may include more than four spaced apart washing stations, such as, but not limited to, five, six, seven, eight, nine, ten or more than 10 washing stations, each of which may include a faucet, sink, soap dispenser and paper towel dispenser. 
     As the hand washing unit accommodates multiple spaced apart users at one time, it may be ideally suited for use during outbreaks of pathogens that may be spread through the air. The hand washing unit may be utilized at such locations where enhanced socially or physically distanced hand washing is required, such as hospitals or other medical facilities. For example, in response to a virus outbreak or natural disaster, the hand washing unit may be rapidly deployed to the site of a field hospital or other emergency response location. 
     With reference now to  FIGS. 1A-1E, 3 and 4 , a hand washing unit according to a first embodiment of the present disclosure is shown generally as  10 . Hand washing unit  10  may include a base unit  12 , housing  14 , four washing stations  16   a ,  16   b ,  16   c  and  16   d , a fresh water tank  60 , a water pump  66 , a heating and mixing system  82  and a waste water tank  62 . 
     In this embodiment, the base unit  12  supports the hand washing unit  10  and is a trailer base, which includes a generally rectangular frame  18 , with three connecting members  20   a ,  20   b ,  20   c  extending from the front of frame  18  ( FIG. 1E ). Connecting members  20   a ,  20   b  may be arranged in a generally V-shape, with member  20   c  extending therethrough. Frame  18  and connecting members  20   a ,  20   b ,  20   c  may be manufactured from any suitable material such as tubular steel (for example 3 inches by 2 inches tubular steel) and may be fixedly connected by any method, such as by welding. 
     Located at the distal end of member  20   c  is a ball hitch  22  which is sized and configured to attach to the tow hitch of a vehicle (not shown). When the ball hitch  22  is unattached to the vehicle, the front end of hand washing unit  10  may be supported by jack  24  which may be adjusted to ensure unit  10  is substantially level. 
     The rear of trailer base  12  is supported by a single axle  28  attached to frame  18  and also includes rotatably mounted wheels  30   a  and  30   b  on the respective left and right sides of unit  10 . Wheels  30   a  and  30   b  are sized to support the overall weight of the hand washing unit  10 . 
     With reference to  FIG. 1E , affixed to the top surfaces of members  20   a ,  20   b ,  20   c  at the distal end may be a mounting plate  34 , affixed by a suitable method, such as welding. Mounting plate  34  functions to provide a surface for a pair of propane tanks  36  to be mounted and also provides additional strength and rigidity to frame  18 . A securing device  38 , such as a clamp or adjustable strap, operates to securely retain propane tanks  36  in the illustrated position. 
     Housing  14  may be a generally rectangular structure, comprising front panel  14   a , rear panel  14   b  and respective left and right panels  14   c  and  14   d , extending upwards from trailer base  12 . The upper surface of housing  14  is defined by top panel  14   e , flanked by respective left and right sloped panels  14   f  and  14   g . Panels  14   a - 14   g  may be made from any suitably strong material, such as PVC coated aluminium, and may be affixed together by any suitable method, such as riveting. 
     As depicted in  FIG. 1B , panel  14   c  may include outwardly opening access doors  15  and  17 . Doors  15  and  17  may be opened from the closed configuration shown in  FIG. 1B  to the open configuration depicted in  FIG. 3  and allow access to the internal components of hand washing unit  10 . When in the closed configuration, doors  15  and  17  are secured by locks  15   a  and  17   a  respectively. 
     Positioned at each upper corner of housing  14  are washing stations  16   a - 16   d  which may be constructed from similar materials in a similar manner and are operable to wash a user&#39;s hands or face or other object. Washing station  16   a  is shown in greater detail in  FIGS. 1F and 1G  and includes a sink  40   a  and a faucet  42   a . Sink  40   a  may include a sink base  43   a , which slopes outwardly from the centre of unit  10  in order to direct clean water dispensed from the faucet  42   a  towards a drain  44   a . In an embodiment, sink base  43   a  inclines at an angle, θ, of about 3 degrees towards drain  44   a  ( FIG. 1G ). Two side walls  46   a  and backsplash  48   a  ( FIG. 1C ) project vertically upwards from sink base  43   a  and function to minimize splashing and assist in directing clean water towards the drain  44   a . In a similar manner as described above, washing stations  16   b - 16   d  may include sinks  40   b - 40   d , faucets  42   b - 42   d , sink bases  43   b - d , drains  44   b - d , side walls  46   b - 46   d  and backsplashes  48   b - 48   d . Faucets  42   a - 42   b  may be any suitable faucet, such as a ball faucet, disk faucet, cartridge faucet or compression faucet. In one embodiment, faucets  42   a - d  may be cartridge faucets, such as Moen M-Press metering faucets. 
     In an embodiment, sink bases  43   a - d  have a length of between about 10-20 inches or about 12-16 inches or about 14 inches and a width of between about 15-25 inches or about 19-21 inches or about 21 inches. Adjacent washing stations, such as washing stations  16   a  and  16   d  may be positioned between about 75-85 inches or about 78-82 inches or about 81 inches apart from each other, when measuring the distance between drains  44   a  and  44   b.    
     Washing stations  16   a - 16   d  may also include hoods  50   a - 50   d , soap dispensers  52   a - 52   d  and paper towel dispensers  54   a - 54   d . Hoods  50   a - 50   d  may project vertically up from the inboard end of sinks  40   a - 40   d . Soap dispensers  52   a - 52   d  are affixed to the outwards facing side of backsplashes  48   a - 48   d  and may be foaming hand soap dispensers, such as Gojo ADX-12 soap dispensers. Paper towel dispensers  54   a - 54   d  are positioned adjacent to the sinks  40   a - 40   d  and may include a retaining mechanism to hold a paper towel roll. 
     Sinks  40   a - 40   d , backsplashes  48   a - 48   d , hoods  50   a - 50   d  and paper towel dispensers  54   a - 54   d  may be manufactured from any suitable non-porous material, such as stainless steel, metal, composite or plastic. 
     In one embodiment, hood  50   a  may be pivotably connected to backsplash  48   a  through pivotable mechanism  56   a  and is operable to pivot hood  50   a  through 90 degrees from a first position shown in  FIGS. 1A-1D  to a second position shown in  FIGS. 2A-2D . Hood  50   a  may be locked in the second position by hold down latch  58   a . Similarly, hoods  50   b - 50   d  may be movable through respective pivotable mechanism  56   b - 56   d  and secured in a second position with hold down latches  58   b - 58   d.    
     The first position shown in  FIGS. 1A-1D  may be an operational configuration where hoods  50   a - 50   d  function to partially shelter a user from inclement weather, such as wind, snow and rain, and to allow access to paper towel dispensers  54   a - 54   d , which are affixed to inner faces of hoods  50   a - 50   d . The second position shown in  FIGS. 2A-2D  may be a transport or storage configuration, where hoods  50   a - 50   d  advantageously function to shield and protect washing stations  16   a - 16   d  from wind and rain or flying debris, for example. 
     Turning to  FIG. 3 , a partial cross-sectional top plan view of hand washing unit  10  is shown. Positioned approximately centrally within housing  14  and supported by frame  18  may be fresh water tank  60  and waste water tank  62 . Fresh water tank  60  is operable to receive and store a supply of fresh (or clean) water through fill spout  64  ( FIG. 1C ) and is in fluid communication with each of the washing stations  16   a - 16   d . Waste water tank  62  is also in fluid communication with each of the washing stations  16   a - 16   d  and is operable to receive and store waste water (i.e. run-off or dirty water) from the drains  44   a - d  of the sinks  40   a - 40   d . In one embodiment, waste water tank  62  may be positioned directly below fresh water tank  60  such that the tanks  60 ,  62  may exchange heat with each other. This may aid in preventing water stored in tanks  60 ,  62  from freezing during cold weather conditions. 
     In an embodiment, fresh water and waste water tanks  60 ,  62  may both have a length of about 5 feet, a width of about 3 feet and a height of about 1 foot and may have a capacity of about 425 litres. Fresh water and waste water tanks  60 ,  62  may be manufactured form any suitable material, such as stainless steel and may include internal baffles (not shown) to minimize water movement when the unit is being transported to or from a location. In some embodiments, fresh water tank  60  may be secured to waste water tank  62  by any suitable method, such as welding or an adjustable strap. 
     Fresh water tank  60  may be vented though a water fill spout  64 , which exits through panel  14   g  in housing  14  ( FIG. 1B ). Extending through front panel  14   a  may be a AC inlet  19  ( FIG. 1C ), which may be a AC 120V, 15 amp plug, operable to receive AC power from an external source. Waste water tank  62  may be vented through a line (not shown) exiting housing  14  and may be drained through gate valve  80  (see  FIG. 4 ), which may be accessed through access door  17 . Gate valve  80  may also include a hose adaptor for connecting hosing to enable waste water to be drained from waste water tank  62 , such as through connection to a tanker truck. 
     With reference to  FIG. 3 , located within housing  14  and supported by frame  18  is water pump  66 , a heating and mixing system  82  (see  FIG. 4 ) including a water heater  68  and a mixing device or mixing valve  70 , a return valve  72 , a battery  74  and an interior heater  76 . In some embodiments, housing  14  may be lined with insulation  78  which functions to reduce sound generated from the components of unit  10  and to insulate components therein from external temperatures. The water pump  66  may be any water pump suitable to deliver clean water from fresh water tank  60  to the washing stations  16   a - 16   d , such as a self-prime regenerative pump, for example a Shurflo 4048 fresh water pump, a centrifugal pump or pressure booster pump. 
     Water heater  68  may be any heater suitable for heating water, such as a storage tank water heater, a tankless (or on demand) water heater, for e.g. a Truma Aqua Go Comfort Plus water heater, a heat pump water heater or a solar powered water heater. In some embodiments, the water heater  68  may be an electric water heater which converts electricity into thermal heat to heat water. In other embodiments, the water heater  68  may be a propane water heater which uses gas and an internal flame to heat water. In the embodiment shown in the FIGS., the water heater  68  is a propane water heater that is in fluid communication with propane tanks  36  through regulator  37  ( FIG. 1C ). Water heater  68  may be accessed through water heater panel  39  in panel  14   a  of housing  14 . Panel  39  includes a grill  41  to vent exhaust gases from water heater  68  to the atmosphere. 
     Interior heater  76  functions to heat the interior of housing  14  and may be activated during colder weather conditions to prevent water within hand wash unit  10  from freezing. An example of interior heater  76  is a Temro 900 W heater. 
     The battery  74  may be sized and operable to deliver sufficient power to operate the water pump  66 , water heater  68  when an electric water heater, interior heater  76  and any other component within unit  10  that needs power. In one embodiment, the battery may be a 12V battery, such as an AGM 12V battery. 
     With reference now to  FIG. 4 , a block diagram showing a water system  100  for use in hand washing unit  10  of the present disclosure is shown. A volume of clean water may be loaded into and stored in fresh water tank  62  through water fill spout  64 . The clean water loaded into fresh water tank  60  may be from any suitable source known to those skilled in the art, such as a tanker truck or mains supply. The term “fresh” (or “clean”) water as used herein refers to water suitably pure and free of contaminants so as can be used for hand washing. Clean water is dispersed from fresh water tank  60  by water pump  66 . Thus, fresh water tank  60  is in fluid communication with water pump  66 . In overview, water pump  66  is operable to disperse clean water from water tank  60  and supply clean water to washing stations  16   a - 16   d  and in particular, faucets  42   a - 42   d . A heating and mixing system  82 , comprising a water heater  68  and mixing device or mixing valve  70 , is in fluid communication with the outlet of water pump  66 . Thus, water pump  66  is operable to supply clean water from fresh water tank  30  directly to mixing device or valve  70  and to supply clean water from fresh water tank  60  to water heater  68 , which is in turn in fluid communication with mixing valve  70 . Water heater  68  is operable to raise the temperature of water passing therethrough yielding heated water with an elevated temperature relative to the temperature of the clean water supplied to water heater  68 . Mixing device or mixing valve  70  is in fluid communication with faucets  42   a - 42   d . In one embodiment, mixing valve  70  is a thermostatic mixing valve and is operable to blend the heated water from water heater  68  and clean water from fresh water tank  60  to produce a supply of clean water to faucets  42   a - d  at a pre-determined temperature. The mixing valve  70  may be adjusted accordingly in order to vary the pre-determined temperature of clean water supplied to faucets  42   a - 42   d . In one embodiment, the pre-determined temperature may be a temperature within the range of about 35°−40° C. In another embodiment, mixing device  70  is an in-line static mixer and is operable to blend the heated water from water heater  68  and clean water from fresh water tank  60  to produce a supply of clean water to faucets  42   a - 42   d  at the pre-determined temperature above. 
     Water system  100  may also include a return valve  72  which is in fluid communication with the outlet of water heater  68  and fresh water tank  60 . and when opened, controls a flow of heated water from water heater  68  to fresh water tank  60 . This may be desirable in order to raise the temperature of the clean water in fresh water tank  60 , for example, in order to prevent the clean water in fresh water tank  60  from freezing. As described above, fresh water tank  60  may be positioned directly above waste water tank  62  such that heat from tank  60  may radiate towards waste water tank  62  to assist in preventing the waste water in waste water tank  62  from freezing. Thus, water system  100  is capable of operating at temperatures at or below as −15° C. and is therefore suitable for multi-season use in North America and other parts of the world. 
     Clean water is dispensed though faucets  42   a - 42   d , and after washing, is collected in respective sinks  40   a - d  as waste water. Waste water may contain contaminates such as dirt, grease, oil, soap or food. In overview, waste water is collected in sinks  40   a - 40   d  and passed through drains  44   a - d  which are in fluid communication with waste water tank  62 . Waste water tank  62  is operable to receive and store waste water from sinks  40   a - 40   d  prior to appropriate water treatment or disposal through gate valve  80  ( FIG. 3 ). 
     In the embodiment shown in  FIG. 4 , waste water from sinks  40   a  and  40   c , located at the front of hand washing unit  10 , is collected and supplied to waste water tank  62  via a P-Trap  84 . In a similar manner, waste water from sinks  40   b  and  40   d , located at the rear of hand washing unit  10 , is collected and supplied to waste water tank  62  via a P-Trap  86 . 
     During use, a user may activate any one of faucets  42   a - 42   d  which causes clean water at the pre-determined temperature to be dispensed through the activated faucet for a pre-determined time. Waste water, after washing, is collected in sinks  40   a - 40   d  and flows into waste water tank  62  where the waste water may be stored. Using a faucet operable to deliver clean water for a pre-selected cycle time may ensure sufficient time for a user to maintain good hand washing practices, without the use of excess clean water. 
     As one skilled in the art will appreciate, the water system  100  can adopt any other suitable configuration in order to supply water from a fresh water tank to any number of separated washing stations, and collect and combine the waste water in a waste water tank. 
     Any of the fluid connections described above may be achieved through any conventional tubing or piping known to those skilled in the art. For example, such connections may be achieved through polyvinyl chloride (PVC), chlorinated polyvinyl chloride (CPVC), copper, galvanised steel piping, stainless steel, cross-linked polyethylene (PEX) pipes, polypropylene or other similar plumbing fixtures. In a preferred embodiment hand washing unit  10  uses PEX piping. 
     In other embodiments, water system  100  may be configured to supply separate streams of heated and unheated clean water from fresh water tank  102  to separate hot and cold water faucets of a washing station. For example, water pump  66  may pump clean water from fresh water tank  60  directly to cold water faucets through a cold water outlet. Thus, the cold water outlet of water pump  66  is in fluid communication with the cold water faucets of each washing station. For heated water, water pump  66  may pump clean water to water heater  68  through a hot water outlet. Thus, the hot water outlet of water pump  66  is in fluid communication with the water heater  68 . Upon receiving clean water, water heater applies heat to the clean water to raise the temperature of clean water to produce warm or hot water which can then be supplied to hot water faucets of the washing stations. Thus, the water heater  68  is in fluid communication with the hot water faucets. 
     Referring now to  FIG. 5 , battery  74 , which may be an AGM DC 12V battery, powers water pump  66  and water heater  68  when water heater  68  is an electric water heater, and interior heater  76  (not shown). When hand washing unit  10  is in use, water pump  66  may be activated by switch  88 , which is positioned on the outer surface of panel  14   c  of housing  14  ( FIG. 1B ). Water heater  68  may be in communication with a control panel  98 , which may be located behind access door  15 , adjacent to battery  74 . Battery  74  may also be in electrical communication with a battery charger  90  which is operable to maintain the charge of battery  74  when connected to an AC power supply though AC inlet  19 . 
     Where hand washing unit  10  includes a trailer base  12 , the unit may further include tail lights  94  ( FIG. 1C ) affixed to panel  14   b  and clearance lights  96  ( FIGS. 1A and 1B ), affixed to panels  14   c  and  14   d.    
     In another embodiment, the base unit of hand washing unit  10  is a skid base which may be moved by any suitable vehicle such as a forklift truck. For transporting over longer distances, the hand wash unit  10  may be loaded onto a truck and transported to the desired location. In this configuration, larger fresh and waste-water tanks may be advantageously accommodated as the hand washing unit may be transported on a vehicle with larger weight capacity, such as a semi-trailer. This will enable a greater number of hand washes between servicing of the unit. 
     In other embodiments, the hand washing unit  10  may be configured to receive an external supply of clean water and may be connected to an external drain or waste water tank, enabling continuous use without the requirement to refill or empty the fresh and waste water tanks. When the unit is also connected to an AC power source, uninterrupted use of the hand washing unit may be achieved which may be advantageous when the hand washing unit is required for use for a prolonged period of time, or by a high volume of users. 
     Clean water may be supplied to each of the washing stations at any suitable temperature through adjustment of the thermostatic mixing valve. In a specific embodiment water is supplied to the faucets of the washing station at about 35° C.-40° C., such as about 38° C. The faucets may be configured to supply water for a fixed period of time in order to encourage compliance of the user to best hand washing practices without wasting water. In a specific embodiment the faucet may supply water a constant flow rate for a time period of about 20-25 seconds, such as about 22 seconds. This will also prevent the faucet from unintentionally being left running. 
     In another embodiment, the hand washing unit  10  may include an electric hand drier which may be connected to the onboard DC power supply or connected to an external power supply, if available. 
     In another embodiment as noted above, water heater  68  may be an electric water heater, such as an electric immersion heater powered solely by battery  74  or through an electrical outlet. 
     In a further embodiment, a hand washing unit of the present disclosure may be in fluid communication with at least one external slave washing station which may be configured in a similar manner to the washing stations described above, but operating as a separate, stand-alone unit. When connected to an external slave washing station, the hand washing unit functions to supply fresh water to and remove grey water from the slave washing station. This may allow more users to be accommodated or to increase the spacing between users. 
     In an embodiment, at least one of the hand washing stations or slave washing stations may be ADA (American Disabilities Act) compliant. 
     While the foregoing is directed to various embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.