Abstract:
An oil pump unit includes an additional outlet port connected to the downstream side of the pump through the pump cover. With this additional port, the oil pump unit is able to have electronic vacuum and pressure sensors upstream and downstream of the pump for remote monitoring of the pump. The invention is particularly suited for oil pump units which have a main discharge outlet port through the one side of the pump body and a main inlet port through an opposing side of the pump cover. The invention is also particularly suited for oil pump units having a solenoid valve mounted at the top side of the pump body which prevents installation of a pressure sensor along the top side.

Description:
FIELD OF THE INVENTION 
   This invention pertains to fuel pumps, and more particularly to port configurations of fuel pumps having a pump body and a cover. 
   BACKGROUND OF THE INVENTION 
   Fuel oil pump units are used to pump fuel oil to oil burning furnaces for heating residential and commercial buildings. By virtue of the application and where furnaces are located, fuel oil pump units often are required to fit a small confined area of a predetermined package size. Examples of fuel oil pump units are disclosed in U.S. Pat. Nos. 3,360,190; 3,446,230; 3,446,231; 3,446,232; 3,566,901; 4,021,155; 4,171,939; 4,255,093; 4,391,580; 4,685,871; 4,728,271; 4,856,553; 4,858,884; 4,898,523; 4,958,997; 5,145,328; 5,316,457; 5,346,174; and 5,692,680, and application Ser. Nos. 10/017,153 and 10/115,742, all assigned to the present assignee, and all of which are hereby incorporated by reference in their entireties. 
   As disclosed in these patents and patent applications, the basic structural design for an oil pump unit typically comprises a pump body often formed of cast iron and a pump cover often formed of aluminum. The pump body typically contains a crescent type gear pump that pumps fuel oil from a local reservoir (defined between the pump body and pump cover) that is supplied oil from a fuel oil storage tank. The pump unit also comprises a fuel regulator that is adapted to regulate flow of fuel oil from the gear pump to a nozzle outlet passage. The nozzle outlet passage is adapted to be connected to the combustion chamber of a furnace. 
   To a large extent, this basic structural design has remained the same and has provided excellent reliability, low cost and other desirable characteristics. The present assignee, Suntec® Industries, has manufactured and continues to manufacture a number of different commercially successful models of oil pump units incorporating this basic structural design. 
   Many years ago, most oil pump units had a mechanically actuated fuel regulator (e.g. such as a pressure sensitive diaphragm valve which is used to control the opening and closing of the regulator). However, many of the more modern designs (which have retained the basic structural design of mechanically controlled regulators) now incorporate electronic control of the regulator, such as may be provided an electrically actuated solenoid valve. As a result of this trend, many current Suntec® models of fuel oil pump units now incorporate a solenoid valve. The solenoid valve is typically mounted on the top side of the pump body which is often the most convenient location to provide for control over the fuel regulator. Because solenoid control based designs have been in existence for a number of years, there is a large number of existing Suntec® oil pump units having solenoid valve control that are currently employed in the field. 
   As will be readily appreciated by maintenance and service technicians in the industry, oil pump units must be replaced or repaired from time to time due to normal wear and usage. Because existing applications need to be serviced and replaced from time to time, any design changes to an existing model of an oil pump unit typically require a pump unit configuration with about the same package size in order to properly fit into the available space for existing applications. Also, the oil pump unit must typically provide the same port configuration to provide for ready connection to the existing furnace and supply line plumbing. 
   The next future trend in the fuel oil heating industry will likely be to provide smart feedback to oil pump unit and furnace systems. Sensors may be employed to monitor various burner parameters such as pressures, temperatures and flame brightness. From this feedback, it can be determined if the oil pump unit is operating properly. The data will be transmittable to remote locations (e.g. via phone lines) for remote monitoring by service technicians who normally service and maintain oil pumps units and associated furnaces. To accommodate this trend, systems will need to incorporate a pressure sensor and a vacuum sensor. 
   Some models of oil pump units already have two inlet side ports upstream of the gear pump and two outlet ports downstream of the gear pump. With extra ports already provided in this configuration, these models of oil pump units can readily accommodate a vacuum sensor on the inlet side and a pressure sensor on the outlet side. However, many models of oil pump units do not provide an extra outlet side port to accommodate a pressure sensor. This presents a problem since as discussed above, the existing package size, design and port configuration can not readily be changed due to the need to accommodate existing applications, which often require a given package size and port configuration. 
   One solution conceived by the present inventor is to provide an additional outlet pressure port along the top side of the pump body to accommodate a pressure sensor. This may provide a solution for oil pump models that are mechanically controlled solely through diaphragm valves (i.e. models without solenoid valves). However, in solenoid valve type models, the solenoid valve is typically mounted to the top side of the pump body. Therefore, in designs incorporating solenoid valves such as Suntec® model nos. A2EA-6520, A2VA-3006 and A2VA-5006, there is not room to provide an additional port to receive a pressure sensor along the top side of the pump body. A potential and previously unknown solution to this issue which has been conceived by the present inventor is to provide an external connection in the plumbing such as providing a t-section in the external copper tubing that connects to the single nozzle outlet provided by oil pump unit. However, this location is somewhat inaccessible when the burner is mounted to the appliance (boiler or furnace). This also would increase the cost and number of parts for oil burner systems. 
   BRIEF SUMMARY OF THE INVENTION 
   The present invention provides a solution to the problems presented in the art as discussed above by providing an additional outlet port connected to the downstream side of the pump through the pump cover. The present invention is particularly suited for oil pump units which have a main discharge or outlet port through the one side of the pump body and a main inlet port through an opposing side of the pump cover (e.g. left and right sides when viewed from the front). The present invention is also particularly suited for oil pump units having a solenoid valve mounted at the top side of the pump body which prevents installation of a pressure sensor along the top side. The new pressure port may be defined through the front side of the pump cover and connected through a passageway formed at least in part by the pump cover to the downstream side of the pump. This provides an accessible location for mounting of a pressure sensor for remote monitoring. 
   It is an advantage of the present invention that existing models and designs of oil pump units can be redesigned to include this additional port without having to change the pump unit package size or the existing port configuration. Thus, the present invention provides for an additional operation feature while keeping the existing pump unit configuration such that the pump unit and its parts continue to be suitable as a replacement unit for existing applications in the field. 
   Other aspects, objectives and advantages of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic representation of a oil pump unit incorporated in a oil pumping system for a furnace or boiler, in accordance with a preferred embodiment of the present invention. 
       FIG. 2  is a perspective view of the oil pump unit shown in  FIG. 1  as it is hooked up to a burner according to an embodiment of the present invention. 
       FIG. 3  is a top view of the oil pump unit shown in  FIG. 1 . 
       FIG. 4  is a frontal view of the oil pump unit shown in  FIG. 2 . 
       FIG. 5  is a bottom view of the oil pump unit shown in  FIGS. 2 and 4 . 
       FIG. 6  is a cross section of  FIG. 5  taken about line  6 — 6  with a different type of regulating valve shown in comparison to  FIG. 1 . 
       FIG. 7  is a cross section of  FIG. 4  taken about line  7 — 7 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   As shown in the drawings, the invention is embodied in a fuel oil pump unit  10  of the type used to supply fuel to the combustion chamber  11  of a burner such as might be incorporated into a furnace or boiler. The unit  10  includes a gear pump  15  that draws fuel oil or other suitable fuel from an oil supply such as a tank  12  through an intake line  13 . 
   The gear pump  15  is contained within a pump housing that is comprised of a pump body  14  (preferably made of cast iron) and a pump cover  16  (preferably made of aluminum). The pump cover  16  is bolted to the pump body  14 . The gear pump  15  is illustrated as the conventional crescent type and includes an inner gear  17  within the housing that is attached to a drive shaft  18  and that is eccentrically disposed with respect to an outer gear  19 . A crescent-shaped member  20  is disposed between the non-engaging portions of the teeth on the gears for the purpose of sealing the expanding fluid chambers defined by the gears from the contracting fluid chambers in a well known manner. 
   The pump shaft  18  is journalled in the pump body  14  and is sealed with respect thereto by an elastomeric sealing member which herein is shown in the form of a lip seal  22 . The lip seal  22  is disposed within and seals off a lubrication chamber  23  in the housing. 
   The pump  15  includes an inlet side that communicates with a local fuel oil reservoir  26  that receives fuel oil from the main oil supply or tank  12 . The pump cover defines an inlet port  28  to which the intake line  13  (often provided by copper tubing) from the storage tank  12  may be connected. The local fuel oil reservoir  26  is defined in a chamber formed between the pump body  14  and the pump cover  16 . More specifically, the pump cover  16  includes a front side  48  and a rearwardly extending sidewall  50  that spaces the front side  48  forward of the pump body  14  and that encloses the fuel reservoir  26 . Along the inlet side, the pump  15  includes a pump inlet  25  that is connected by an inlet passage  27  through the pump body  14  to the reservoir  26 . 
   A suitable strainer  30  may be located within the reservoir  26  between the inlet port  28  and the pump inlet  25  to filter the fuel oil as it is drawn from the tank to the pump  15 . The pump  15  pressurizes the fuel oil and outputs fuel into an outlet passage  32  along the downstream side of the pump  15 . A bleed valve  33  may be disposed along the outlet passage  32 . The outlet passage  32  ultimately delivers fuel oil to a main regulating valve assembly  34  that serves to regulate the pressure of fuel oil and causes fuel flow to the burner  36  to be of a substantially constant pressure. 
   The regulating valve assembly  34  is located in the pump body  14  and serves to control the fuel flow from the outlet passage  32  to an outlet port  41  defined by the pump body  41 . A fitting  39  may be mounted into the outlet port  41  of the pump body  14 . Copper tubing  38  or other suitable conduit means is mounted to the fitting  39  to connect the outlet port  41  of the pump body  14  to the burner  36 . 
   The fitting  39  also provides a valve seat  40  for the regulating valve assembly  34 . The valve seat  40  is adapted to be closed by a spring biased hollow piston  42 . The piston  42  is slidably mounted in a pressure chamber  44  and is spring biased to regulate fuel flow entering the chamber  44 . 
   The opening and closing of the regulating valve assembly  34  is controlled with a solenoid valve  58  that is mounted to the top side of the pump body  14 . As shown herein, the solenoid valve  58  is of the blocking type, but it alternatively may be of the bypassing type or other suitable control arrangement. The solenoid valve  34  controls opening of the regulating valve assembly  34  (i.e., the outlet port of valve assembly  34 ) to the outlet passage  32  upon startup and controls closing of the regulating valve assembly  34  upon shut down. The solenoid valve  58  includes an electrical control element  66  drives a movable valve element  62  between open and closed states to cause pressure to build or be relieved such that the spring biased piston  42  either opens or closes a bypass passage  60  that recirculates fuel to either the tank  12  or local reservoir  26 . 
   The electrical control element  66  may include a thermistor providing a desired time delay for switching the solenoid valve between states. Alternatively, an electronic control (not shown) for the burner may provide the means to control activation of the solenoid control element. In either event, a delay is typically provided in order to provide sufficiently high pump speed and fuel pressure; and also to allow the speed of the blower (not shown), which is driven by the same shaft  18  as the pump  15  to be sufficient to establish a good draft up the chimney  72  of the burner  36 . 
   The disclosed embodiment may also or alternatively include a diaphragm valve  74  or other similar bypass mechanism arranged in parallel circuit with the first bypass mechanism of the solenoid valve  58  and/or the regulating valve assembly  34 . In the disclosed embodiment, the diaphragm valve serves as a redundant backup to the solenoid valve  58  to better ensure the proper opening of the fuel regulating valve assembly  34  at an appropriate time. Such a redundant bypass arrangement is disclosed in patent application Ser. No. 10/017,153 filed on Dec. 14, 2001. The diaphragm valve  74  causes the pump  15  to reach a high start-up rpm before the regulating valve assembly  34  opens and causes the regulating valve assembly  34  to close after the pump  15  falls below a certain rpm upon shutdown. The diaphragm valve  74  is adapted to open or close a second return passage  81  leading back to the pump reservoir  26  (or alternatively to the tank  12 ). To provide for proper operation of the diaphragm valve, a cone valve  82  is arranged upstream of the diaphragm valve to provide a restriction and pressure drop that determines when the diaphragm valve  74  closes the second return passage  81 . 
   As long as the speed of the pump  15  is relatively low, the diaphragm valve  74  remains open to prevent a build up of pressure in the chamber  44  of the regulating valve assembly  34  sufficiently such that the regulating valve assembly  34  remains closed via the spring biased piston  42 . However, as the pump speed increases, the increased flow past the cone valve  82  causes a pressure differential in the diaphragm valve to overcome the force of a spring and close the diaphragm valve causing all of the fuel flow to flow from the pump  15  through the outlet passage of the pump body  14  to the regulating valve assembly  34 . 
   In the disclosed embodiment, the diaphragm valve  74  acts as a back up for the solenoid valve  58  to better ensure that smoking or soot production does not occur in the combustion chamber  11 . The regulating valve assembly  34  remains closed as long as either the diaphragm valve  74  remains open or the solenoid valve  58  remains closed , thereby causing the piston  41  to be wide open and cause flow to bypass along bypass passage  60 . The regulating valve assembly  34  opens and outputs fuel to the furnace only after the diaphragm valve  74  closes and the solenoid valve  58  opens. Once this happens (which is typically very quickly), all of the fuel flow is pumped by the gear pump  15  through the outlet passage  32  and the outlet port  41 . 
   In accordance with the present invention, the oil pump unit  10  provides a port arrangement that substantially maintains size package of prior solenoid type models, while also accommodating inlet side and outlet side electronic pressure gauges  84 ,  86 . As is evident from the foregoing, one inlet port  28  is provided to receive fuel from the tank  12 , and one outlet port  41  is provided to output pressurized fuel to the burner  36 . 
   To accommodate the inlet side electronic pressure gauge  84  at least one additional inlet side port  88  is provided in the bottom side of the pump body  14 . The inlet side port  88  is constantly in fluid communication with the local reservoir  26  and subject to the pressure experienced in the local reservoir  26  upstream of the pump  15 . As a result, the pressure experienced at the inlet side pressure gauge  84  is the vacuum pressure that is upstream of the pump  15 . The inlet side pressure gauge  84  provides electronic feedback representing sensed vacuum pressure on an electrical line  90  which may be transmitted via telephone lines or a wireless transmitter to a remote location. Such data that is transmitted over the electrical line  90  is indicative of whether the oil pump unit  10  is properly operating. 
   To accommodate the outlet side electronic pressure gauge  86 , an outlet side port  92  is formed into the front side of the pump cover  16 . Because the pump cover  16  is upstream of the pump  15 , a formed passage  94  is provided through the pump cover  16  and the pump body  14  that bypasses the reservoir  26  to be in direct fluid communication with the outlet port  41  on the downstream side of the pump  15  and downstream of the solenoid valve  58 . With this arrangement, the outlet side port  92  is in constant communication with the pressure generated by the pump  15  when the solenoid valve  58  is open. With the given arrangement, downstream of the solenoid valve  58 , the outlet side pressure gauge  86  will also indicate if the solenoid valve and regulating valve assembly are properly operating. The outlet side pressure gauge  86  is mounted into the outlet side port  92  and provides electronic feedback on an electrical line  96 . The pressure gauge data on electrical line  96  may be transmitted on telephone lines or a wireless transmitter to a remote location. 
   The data from the pressure gauges  84 ,  86  can be used at a remote location to determine whether the oil pump unit  10  is properly operating. If the data indicates a problem, a service technician can be sent to maintenance, repair or replace the oil pump unit  10 . The source of the problem might be also be indicated by the gauges  84 ,  86  such that the service technician can anticipate the solution and be prepared during a maintenance visit. 
   The illustrated pump unit  10  also provides a port arrangement that is suitable for use with existing applications. For purposes of orientation, and as shown in  FIGS. 2–5 , a front side  98  of the fuel pump unit  10  is provided by the pump cover  16 . With this orientation, the pump unit  10  has a top side  99 , a bottom side  100 , a right side  101 , and a left side  102 . The main fuel inlet port  28  is provided along the right side  101  of the pump unit  10  in the pump cover  16 , and is in a conventional position to connect to existing tank intake lines (e.g. such as intake line  13  as shown) without additional plumbing. Likewise, the main fuel outlet port  41  is on the left side of the pump unit  10  in the pump body  14 , and is in a conventional position to connect to existing outlet passage conduits (e.g. tubing  38 ) without additional plumbing. The inlet side port  88  formed in the bottom side  100  (adjacent a return port  89  that provides an option of connecting to the tank  12 ) receives the electronic inlet side pressure gauge  84 . Because the solenoid valve  58  occupies the top side of the pump body  14 , the other pressure gauge  86  is mounted into the front side  98  of the pump unit  10  through the outlet side port  92  formed into the front side of the pump cover  16 . To accommodate the outlet side port  92  and communicating pressure passage  94 , the pump cover  16  may include a raised boss or projection  105  to ensure sufficient material is provided to form the port  92  and passage  94 . 
   All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein. 
   The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention. 
   Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.