Wave soldering tank

Patent metadata

Field	Value
Publication number	US-9956633-B2
Application number	US-201213527532-A
Country	US
Kind code	B2
Filing date	Jun 19, 2012
Priority date	Oct 10, 2003
Publication date	May 1, 2018
Grant date	May 1, 2018

Abstract

A wave soldering tank includes a soldering tank body for housing molten solder and a solder feed chamber disposed within the soldering tank body. An axial-flow, multiple-blade screw-type pump is disposed so as to draw molten solder into the solder feed chamber through an inlet and discharge the molten solder through an outlet. In a preferred embodiment, the pump includes a rotatable hub and a plurality of helical blades secured to the hub at equal intervals in the circumferential direction of the hub, each of the blades overlapping an adjoining one of the blades when the blades are viewed in the axial direction of the impeller.

First claim

What is claimed is:

1. A soldering tank comprising:
a soldering tank body for housing molten solder;
a nozzle for discharge of molten solder, the nozzle having an upper end disposed above a level of molten solder in the tank body;
a motor;
a four-blade screw-type pump fluidly communicating with the nozzle to supply molten solder from inside the tank body to the nozzle, the pump comprising a shaft rotated by the motor, a screw which is secured to a lower end of the shaft and has a hub with a vertical rotational axis and four helical blades which are secured to the hub with each of the blades overlapping an adjoining one of the blades in a circumferential direction of the screw when viewed in an axial direction of the screw and extending only partway around a circumference of the screw, and a cylindrical casing in which the screw is rotatably disposed so as to transport molten solder vertically in an axial direction of the casing, rotation of the screw causing molten solder to pass vertically through the casing and be discharged from the pump and then discharged from the nozzle; and
a horizontal solder feed chamber which receives all the molten solder which is discharged from the pump and transports all the molten solder which is discharged from the pump to the nozzle,
wherein the casing has an upstream end, a downstream end which opens onto an interior of the solder feed chamber, a cylindrical inner surface which extends from the upstream end to the downstream end of the casing, and a single inlet for molten solder, the inlet being disposed at the upstream end of the casing concentrically with a longitudinal axis of the casing,
and wherein during operation of the pump, molten solder flows within the casing in the axial direction of the casing while contacting the inner surface of the casing over an entire length of the inner surface and is discharged vertically from the pump into the solder feed chamber from multiple locations in the circumferential direction of the screw towards a surface of the solder feed chamber intersected by a line coaxial with the screw and then flows vertically within the solder feed chamber away from the pump into contact with the surface of the solder feed chamber and then flows horizontally within the solder feed chamber and then flows upwards from the solder feed chamber into the nozzle without passing through a flow straightening plate between the pump and the nozzle and then is discharged from the nozzle as a solder wave.

2. A soldering tank as claimed in claim 1 wherein a radial clearance of 0.1-1 mm is present between the casing and the screw.

3. A soldering tank as claimed in claim 1 wherein the casing has an overall length in the axial direction of the casing which is no longer than an overall length of the screw in the axial direction of the screw.

4. A soldering tank as claimed in claim 1 wherein rotation of the screw causes molten solder to be discharged from the nozzle with substantially no undulations in the height of the molten solder discharged from the nozzle.

5. A soldering tank as claimed in claim 1 wherein each of the blades is sloped by at most 45° with respect to a plane perpendicular to the rotational axis of the hub.

6. A soldering tank as claimed in claim 1 wherein:
the inner surface of the casing extends continuously without any opening in the inner surface from the upstream end to the downstream end of the casing; and
the casing surrounds the screw over an overall length of the screw in the axial direction of the screw.

7. A soldering tank as claimed in claim 6 wherein the casing has an overall length in the axial direction of the casino between its upstream end and its downstream end which is the same as the overall length of the screw in the axial direction of the screw.

8. A soldering tank as claimed in claim 1 wherein:
the inner surface of the casing extends continuously without any opening in the inner surface from the upstream end to the downstream end of the casing; and
each of the blades has an upstream end and a downstream end, and the downstream end of each blade is substantially flush with the downstream end of the casing.

9. A soldering tank as claimed in claim 8 wherein the downstream end of each blade is no more than 10 mm out of flush with the downstream end of the casing.

10. A soldering tank as claimed in claim 8 wherein no portion of the screw extends outside of the upstream end of the casing.

11. A soldering tank as claimed in claim 1 wherein each of the blades extends by at most 210 degrees in the circumferential direction of the screw.

12. A soldering tank as claimed in claim 1 wherein the inner surface of the casing extends continuously without any opening in the inner surface from the upstream end to the downstream end of the casing.

13. A soldering tank comprising:
a soldering tank body for housing molten solder;
a nozzle for discharging molten solder, the nozzle having an upper end disposed above a level of molten solder in the tank body;
a motor;
a four-blade screw-type pump fluidly communicating with the nozzle to supply molten solder from inside the tank body to the nozzle, the pump comprising a shaft rotated by the motor, a screw which is secured to the shaft and has a hub having a rotational axis and four helical blades which are secured to the hub with each of the blades overlapping an adjoining one of the blades in a circumferential direction of the screw when viewed in an axial direction of the screw and extending only partway around a circumference of the screw, and a cylindrical casing in which the screw is rotatably disposed so as to transport molten solder in an axial direction of the casing from an upstream end to a downstream end of the screw; and
a duct which has an upstream portion which is intersected by a line coaxial with the rotational axis of the hub and a downstream portion which is disposed beneath the nozzle,
wherein the casing has an upstream end, a downstream end which opens onto an interior of the duct, a cylindrical inner surface which extends from the upstream end to the downstream end of the casing, and a single inlet for molten solder, the inlet being disposed at the upstream end of the casing concentrically with a longitudinal axis of the casing,
and wherein during operation of the pump, molten solder flows within the casing in the axial direction of the casing while contacting the inner surface of the casing over an entire length of the inner surface and is discharged from the pump in the axial direction of the screw into the duct from multiple locations in the circumferential direction of the screw towards a surface of the upstream portion of the duct and then flows in the axial direction of the screw away from the pump and into contact with the surface of the duct and then flows in a lengthwise direction of the duct to the downstream portion of the duct and then flows upwards from the duct into the nozzle without passing through a flow straightening plate between the pump and the nozzle and then is discharged from the nozzle as a solder wave.

14. A soldering tank as claimed in claim 13 wherein each of the blades extends by at most 210 degrees in the circumferential direction of the screw.

15. A soldering tank as claimed in claim 13 wherein during operation of the pump, molten solder is discharged from the downstream end of the screw, and the duct always receives all the molten solder which is discharged from the downstream end of the screw.

16. A soldering tank as claimed in claim 13 wherein the inner surface of the casing extends continuously without any opening

Assignees

• Takaguchi Akira
• Sato Issaku
• Hashimoto Noboru
• Okamura Junichi
• Senju Metal Industry Co

Inventors

• Takaguchi Akira
• Sato Issaku
• Hashimoto Noboru
• Okamura Junichi

Classifications

• B23K3/0653 Primary

  with wave generating means, e.g. nozzles, jets, fountains · CPC title

• B23K1/08

  Soldering by means of dipping in molten solder · CPC title

• B23K3/08

  Auxiliary devices therefor · CPC title