Ignition oil pump for a boiler fuel system

Abstract

The application discloses a boiler fuel system ignition oil pump, which comprises an inlet cavity, an outlet cavity, a suction cavity, a driving screw, a driven screw and multiple cavities. At least one cavity is sequentially spliced at both ends of the outlet cavity, the inlet cavity is connected at the end of the leftmost cavity of the outlet cavity, and the suction cavity is connected at the end of the rightmost cavity of the outlet cavity. An inlet flange is arranged on the side wall of the inlet cavity, and the conveying medium is sucked into the pump body through the inlet flange. An outlet flange is arranged on the side wall of the outlet cavity, and the conveying medium is discharged from the pump body through the outlet flange. The suction cavity and the side wall of the inlet cavity are further connected with a drainage pipe for connecting the two cavities. The application can efficiently output stable flow under high ignition oil supply pressure, has long service life and ensures long-term reliable and stable operation of a boiler unit.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of boiler fuel oil system equipment, and more particularly to a boiler fuel oil system ignition oil pump. BACKGROUND

[0002] The boiler fuel oil system is an auxiliary combustion system of a power plant boiler, and its main function is to provide auxiliary fuel during unit startup and load change to ensure safe and reliable operation of the boiler unit.

[0003] In order to successfully ignite the unit and fully burn the fuel oil, the fuel oil of the boiler must enter the boiler in the form of high-quality atomization, which requires the fuel oil entering the boiler nozzle to have a high pressure. Generally, the ignition oil supply pressure is at least 2.5 MPa. With the increasing requirements of the boiler system, the ignition oil supply pressure is required to reach 4.0 MPa more and more, which puts higher requirements on the boiler ignition oil pump.

[0004] At present, the boiler ignition oil pump is mostly a three-screw pump. However, due to the low viscosity of fuel oil and high oil supply pressure, the pump wears out quickly. According to investigations, the service life of the three-screw pump under the ignition oil supply pressure of 2.5 MPa is generally within 6 months, and it cannot meet the ignition oil supply pressure of 4.0 MPa. In addition, the fuel flow demand of the boiler fuel oil system is small, mostly ≤20 m3 / h, so the multi-stage centrifugal pump is not suitable for this high-pressure small-flow condition.

[0005] Therefore, how to provide a more stable boiler fuel oil system ignition oil pump has become a technical problem to be solved in the field. SUMMARY

[0006] The purpose of the present application is to provide a boiler fuel oil system ignition oil pump that can efficiently output stable flow under high ignition oil supply pressure and has a long service life, thereby ensuring long-term reliable and stable operation of the boiler unit.

[0007] According to one aspect of the present application, a boiler fuel oil system ignition oil pump is provided, which comprises an inlet cavity, an outlet cavity, a suction cavity, a driving screw, a driven screw, and a plurality of chambers.

[0008] At least one chamber is sequentially spliced at both ends of the outlet cavity. The inlet cavity is connected to the end of the leftmost chamber of the outlet cavity, and the suction cavity is connected to the end of the rightmost chamber of the outlet cavity. An inlet flange is provided on the side wall of the inlet cavity, and the conveyed medium is sucked into the pump body through the inlet flange. An outlet flange is provided on the side wall of the outlet cavity, and the conveyed medium is discharged from the pump body through the outlet flange. A drainage pipe is further connected to the side walls of the suction cavity and the inlet cavity to communicate them.

[0009] The end of the import cavity and the suction cavity is also provided with a bearing seat, the driving screw and the driven screw are engaged with each other, the two ends thereof are fixed on the bearing seat through bearings respectively, the driving screw and the driven screw are centered on the outlet cavity, the two sides thereof are respectively provided with threads with opposite rotation directions, one end of the driving screw extends to the outside of the suction cavity and is connected with a driving device, so that the transported medium can be transported bidirectionally from the import cavity and the suction cavity to the outlet cavity.

[0010] Optionally, the two side surfaces of the chamber are both ladder-shaped and parallel to each other, the two side surfaces of the outlet cavity are respectively matched with the side surfaces of the two end chambers, and the opposite side surfaces of the import cavity and the suction cavity are respectively matched with the side surfaces of the chambers.

[0011] Optionally, the outer side walls of the import cavity and the suction cavity are provided with a plurality of corresponding pressing blocks, the opposite pressing blocks are fastened and connected through double-end bolts, so that the import cavity, the outlet cavity, the suction cavity and the plurality of chambers form an integral structure.

[0012] Optionally, the side wall bottoms of the import cavity and the outlet cavity are provided with supports, which are used as mounting feet of the pump.

[0013] Optionally, the drainage pipe is arranged at the side wall bottoms of the import cavity and the outlet cavity.

[0014] Optionally, one end of the driving screw and the driven screw close to the import cavity extends to the outside of the import cavity and is driven through a gear pair.

[0015] Optionally, the driving screw and the driven screw are respectively left with a gap δ between the inner side wall of the pump body.

[0016] Optionally, the value of the gap δ is within 0.1-0.2 mm.

[0017] Optionally, a plurality of throttle grooves are processed on the inner side walls of each chamber and the outlet cavity, an included angle α exists between the throttle grooves and the tooth top surfaces of the driving screw and the driven screw, and the included angle α respectively faces the suction cavity and the import cavity.

[0018] Optionally, according to the boiler fuel system ignition oil pump, the included angle α is between 30° and 45°, the width b of the throttle groove is 3-5 mm, the depth h of the throttle groove is 3-5 mm, and the spacing s between adjacent throttle grooves is 0.5 times the width b of the throttle groove.

[0019] The present application has the following advantages:

[0020] (1) A boiler fuel system ignition oil pump, the double-suction screw structure balances the axial force, and the pump has the ability to adapt to high-pressure working conditions. The screw is driven by a gear, and there is a gap between the screw and the pump body, which has no wear and a long service life.

[0021] (2) The lead size and thread length of the screw are adjusted according to the change of the outlet pressure of the ignition oil pump, so that the pump can achieve different pressure boosting capabilities. Therefore, the same specification pump has multiple specifications of screws. The present application can meet different specifications of screws by adaptively adjusting the length and number of chambers (without replacing the entire pump body), so that the ignition oil pump can meet the working condition requirements of different ignition oil supply pressures.

[0022] (3) The throttle groove is arranged on the inner hole surface of the pump body matched with the outer circle of the screw. The pump body is a whole single part structure, and the pump body will be very long and the entire inner hole will be very deep, making it difficult to process the throttle groove. The present structure only needs to be processed on the chamber and the outlet chamber of a shorter length, which greatly reduces the difficulty of processing the throttle groove and improves the implementability of the throttle groove.

[0023] (4) If local unexpected wear and tear occurs in the pump body, only the corresponding worn parts such as the chamber or the outlet chamber need to be replaced, and the use and maintenance cost is very low.

[0024] (5) The screw outer circle and the matched pump body inner hole maintain an installation gap δ, so that the transported material flows back from the high-pressure side to the low-pressure side along the gap δ. The present application processes multiple throttle grooves on the inner hole surface matched with the screw outer circle of the chamber and the outlet chamber, which can effectively reduce the backflow amount of the transported material.

[0025] Other features and advantages of the present application will become apparent from the following detailed description of exemplary embodiments thereof, taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0026] The accompanying drawings incorporated in and forming a part of the specification illustrate embodiments of the present application and, together with the description, serve to explain the principles of the application.

[0027] Figure 1 is a sectional view of the boiler fuel system ignition oil pump disclosed by the present application;

[0028] Figure 2 Front view of the ignition oil pump of the boiler fuel oil system disclosed in the present invention;

[0029] Figure 3 Front view of the ignition oil pump of the boiler fuel oil system disclosed in the present invention;

[0030] Figure 4 Structure diagram of the throttle groove and the gap δ disclosed in the present invention;

[0031] Figure 5 The present invention Figure 4 Partial enlarged view of the throttle groove and the gap δ in the present invention.

[0032] BRIEF DESCRIPTION OF DRAWINGS 01 - driving screw; 02 - driven screw; 03 - inlet flange; 04 - outlet flange; 05 - bearing seat; 06 - suction chamber; 07 - chamber; 08 - outlet chamber; 09 - inlet chamber; 10 - gear pair; 11 - bearing; 12 - pressing block; 13 - stud bolt; 14 - bracket; 15 - flow guide pipe; 16 - throttle groove. DETAILED DESCRIPTION

[0033] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of components and steps, numerical expressions, and numerical values set forth in these embodiments are not limiting to the scope of the present invention unless otherwise specifically stated.

[0034] The following description of at least one exemplary embodiment is merely exemplary in nature and is in no way intended to limit the scope of the present invention and its applications or uses.

[0035] Techniques, methods, and apparatus known to those of ordinary skill in the relevant art can not be discussed in detail herein, but should be considered as part of the specification, where appropriate.

[0036] In all of the examples shown and discussed herein, any specific values should be interpreted as merely exemplary, and not as a limitation. Thus, other examples of the exemplary embodiments can have different values.

[0037] It should be noted that like references and characters herein relate to like items throughout the figures, and once an item is defined in one figure, it need not be discussed further in subsequent figures.

[0038] According to Figures 1 to 5 As shown in the drawings, the present invention provides an ignition oil pump of a boiler fuel oil system, which comprises an inlet chamber 09, an outlet chamber 08, a suction chamber 06, a driving screw 01, a driven screw 02, and a plurality of chambers 07.

[0039] At least one chamber 07 is sequentially connected to both ends of the outlet cavity 08, the inlet cavity 09 is connected to the end of the leftmost chamber 07 of the outlet cavity 08, and the suction cavity 06 is connected to the end of the rightmost chamber 07 of the outlet cavity 08; the side wall of the inlet cavity 09 is provided with an inlet flange 03, and the conveyed medium is sucked into the pump body through the inlet flange 03; the side wall of the outlet cavity 08 is provided with an outlet flange 04, and the conveyed medium is discharged from the pump body through the outlet flange 04; the suction cavity 06 and the side wall of the inlet cavity 09 are further connected with a drainage pipe 15 for connecting the two.

[0040] The ends of the inlet cavity 09 and the suction cavity 06 are further provided with bearing seats 05, the driving screw 01 and the driven screw 02 are meshed with each other, the two ends of the driving screw 01 and the driven screw 02 are respectively fixed on the bearing seats 05 through bearings 11, the driving screw 01 and the driven screw 02 are centered on the outlet cavity 08, the two sides of the driving screw 01 and the driven screw 02 are respectively provided with threads with opposite rotation directions, one end of the driving screw 01 extends to the outside of the suction cavity 06 and is connected with a driving device, so that the conveyed medium can be bidirectionally conveyed from the inlet cavity 09 and the suction cavity 06 to the outlet cavity 08.

[0041] In the embodiment, the lead size and the thread length of the threads on the driving screw 01 and the driven screw 02 are adjusted according to the change of the outlet pressure of the ignition oil pump, so that the pump has different pressure increasing capabilities, and therefore the same specification pump has multiple specifications of screws. The length and the number of the chambers 07 are only adjusted (without replacing the entire pump body) to meet different specifications of screws, so that the ignition oil pump meets the working condition requirements of different ignition oil supply pressures. If local unexpected wear and tear occurs in the pump body, only the corresponding worn parts, such as the chambers 07 or the outlet cavity 08, need to be replaced, and the use and maintenance cost is very low. The inlet flange direction of the pump is right side in (viewed from the shaft head to the pump), and only the installation orientation of the suction cavity 06 and the inlet cavity 09 is changed, so that the inlet flange direction of the pump is changed to left side in, thereby meeting the requirements of different pipeline arrangements.

[0042] Further, the two side surfaces of the chamber 07 are both ladder-shaped and parallel to each other, the two side surfaces of the outlet cavity 08 are respectively matched with the side surfaces of the chambers 07 at both ends, and the opposite side surfaces of the suction cavity 06 and the inlet cavity 09 are respectively matched with the side surfaces of the chambers 07 that are attached. The positioning and matching connection between the chambers 07 or between the outlet cavity 08, the inlet cavity 09 and the suction cavity 06 are ensured, and in addition, corresponding sealing gaskets can be arranged between each layer of connecting surfaces.

[0043] Further, a plurality of groups of corresponding pressing blocks 12 are arranged on the outer side walls of the suction cavity 06 and the inlet cavity 09, the opposite pressing blocks 12 are fastened and connected through double-headed bolts 13, the sealing gaskets are combined, and the inlet cavity 09, the outlet cavity 08, the suction cavity 06 and the plurality of chambers 07 form an overall structure through the adjustment of the double-headed bolts 13.

[0044] Further, the side wall bottom of the inlet cavity 09 and the outlet cavity 08 are provided with a bracket 14, which is used as the mounting foot of the pump.

[0045] Further, a flow guide pipe 15 is arranged at the side wall bottom of the inlet cavity 09 and the outlet cavity 08. In the present embodiment, the transported material enters from the inlet flange 03, and under the action of gravity, is located at the bottom of the inlet cavity 09. The flow guide pipe 15 is connected at the bottom of the inlet cavity 09 and the suction cavity 06, and in combination with the rotation of the driving screw 01 and the driven screw 02, the transported material is transported to the side of the suction cavity 06 through the flow guide pipe 15, so as to realize the bidirectional transportation of the pump body.

[0046] Further, the ends of the driving screw 01 and the driven screw 02 close to the inlet cavity 09 extend to the outside of the inlet cavity 09, and are engaged and driven through the gear pair 10. The gear pair 10 is located outside the inlet cavity 09, and is closed by a corresponding cover, which plays a role of protecting the driving screw 01 and the driven screw 02, and preventing the engagement and driving of the two by the transported material.

[0047] Further, the driving screw 01 and the driven screw 02 are respectively provided with a gap δ with the inner side wall of the pump body, so that there is a flow gap between the screw and the pump body, no wear, long service life. According to different pressure and pump specifications, the value of the gap δ is within 0.1-0.2mm.

[0048] Further, a plurality of throttle grooves 16 are processed on the inner side wall of each cavity 07 and the outlet cavity 08, and the throttle grooves 16 are provided with an included angle α with the tooth top surface of the driving screw 01 and the driven screw 02, and the included angle α is respectively towards the suction cavity 06 and the inlet cavity 09. It is mentioned above that the outer circle of the screw and the matched pump body inner hole keep a mounting gap δ, so that the transported material flows back from the high pressure side to the low pressure side along the gap δ (such as Figure 5The higher the pressure, the greater the backflow, which greatly affects the efficiency of the pump. The present application has a plurality of throttling grooves 16 on the inner hole surface of the chamber 07 and the outlet chamber 08 cooperating with the outer circle of the screw. On the one hand, when the backflow liquid enters the throttling groove 16 from the gap δ, the flow area of the backflow channel suddenly increases, forming a fluid vortex in the throttling groove 16, which reduces the potential energy of the backflow liquid. The combined effect of the continuous plurality of throttling grooves 16 forms a labyrinth seal effect in the backflow channel, effectively throttling the liquid backflow and reducing the backflow. On the other hand, the throttling groove 16 has an included angle α with the top surface of the screw. When the backflow liquid enters the throttling groove 16, the liquid flows along the throttling groove 16, forming a backflow direction 2 opposite to the backflow direction 1, which causes a large resistance drop in the backflow direction 1, effectively reducing the pressure before and after the throttling groove 16, thereby throttling the liquid backflow. The setting of the throttling groove 16 effectively improves the efficiency of the boiler fuel system ignition oil pump, ensuring that the pump can be used normally under very high ignition fuel pressure.

[0049] Further, the included angle α is in the range of 30° to 45°, the width b of the throttling groove 16 is 3 to 5 mm, the depth h is 3 to 5 mm, and the spacing s between adjacent throttling grooves 16 is 0.5 times the width b of the throttling groove 16, which has a good throttling effect and high implementability.

[0050] In addition, compared with the overall pump body structure of the prior art, the overall single part structure pump body is very long and the entire inner hole is very deep, making it difficult to machine the throttling groove 16 and implement the throttling groove 16. The present application only needs to be machined on the shorter length chamber 07 and outlet chamber 08, respectively, which greatly reduces the machining difficulty of the throttling groove 16 and improves the implementability of the throttling groove 16.

[0051] Although some specific embodiments of the present application have been described in detail through examples, those skilled in the art should understand that the above examples are only for illustration and are not intended to limit the scope of the present application. Those skilled in the art should understand that the above embodiments can be modified without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. A boiler fuel oil system priming pump characterized by, The pump comprises an inlet cavity, an outlet cavity, a suction cavity, a driving screw, a driven screw and a plurality of cavities. Two ends of the outlet cavity are sequentially connected with at least one cavity, the inlet cavity is connected to the end of the leftmost cavity of the outlet cavity, and the suction cavity is connected to the end of the rightmost cavity of the outlet cavity; an inlet flange is arranged on the side wall of the inlet cavity, and the conveying medium is sucked into the pump body through the inlet flange; an outlet flange is arranged on the side wall of the outlet cavity, and the conveying medium is discharged from the pump body through the outlet flange; a drainage pipe is further connected to the side wall of the inlet cavity and the suction cavity to communicate the two cavities. The end of the inlet cavity and the end of the suction cavity are further provided with bearing seats, the driving screw and the driven screw are meshed with each other, the two ends of the driving screw and the driven screw are respectively fixed on the bearing seats through bearings, the driving screw and the driven screw are centered on the outlet cavity, the two sides of the driving screw and the driven screw are respectively provided with threads with opposite rotation directions, one end of the driving screw extends to the outside of the suction cavity and is connected with a driving device, so that the conveying medium can be bidirectionally conveyed from the inlet cavity and the suction cavity to the outlet cavity. The driving screw and the driven screw are respectively spaced apart from the inner side wall of the pump body by a gap δ, and the value of the gap δ is within 0.1-0.2 mm. A plurality of throttling grooves are formed on the inner side walls of each cavity and the outlet cavity, an included angle α exists between the throttling grooves and the tooth top surfaces of the driving screw and the driven screw, and the included angle α respectively faces the suction cavity and the inlet cavity.

2. A boiler fuel system pilot fuel pump in accordance with claim 1 wherein, The two side surfaces of each cavity are ladder-shaped and parallel to each other, the two side surfaces of the outlet cavity are matched with the side surfaces of the two end cavities, and the opposite side surfaces of the suction cavity and the inlet cavity are respectively matched with the side surfaces of the cavities that are attached.

3. The boiler fuel system pilot fuel pump of claim 2, wherein, A plurality of corresponding pressing blocks are arranged on the outer side walls of the suction cavity and the inlet cavity, the opposite pressing blocks are fastened and connected through double-end bolts, so that the inlet cavity, the outlet cavity, the suction cavity and the plurality of cavities form an integral structure.

4. The boiler fuel system pilot fuel pump of claim 3, wherein, Supports are arranged on the side wall bottoms of the inlet cavity and the outlet cavity to serve as mounting feet of the pump.

5. The boiler fuel system pilot fuel pump of claim 4, wherein, The drainage pipe is arranged on the side wall bottoms of the inlet cavity and the outlet cavity.

6. The boiler fuel system pilot fuel pump of claim 1, wherein, One end of the driving screw and the driven screw close to the inlet cavity extends to the outside of the inlet cavity and is meshed and driven through a gear pair.

7. The boiler fuel system pilot fuel pump of claim 1 wherein, The included angle α is within 30°-45°, the width b of the throttling groove is 3-5 mm, the depth h of the throttling groove is 3-5 mm, and the spacing s between adjacent throttling grooves is 0.5 times the width b of the throttling groove.

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