High-precision weighing module with reduced thermal gradient

Patent metadata

Field	Value
Publication number	US-11733084-B2
Application number	US-202117302655-A
Country	US
Kind code	B2
Filing date	May 10, 2021
Priority date	May 11, 2020
Publication date	Aug 22, 2023
Grant date	Aug 22, 2023

Abstract

An integrated high-precision weighing module has a shell, an electromagnetic force sensor, a printed circuit board (PCB), a weighing pan component, a support ring, and an air baffle ring. The electromagnetic force sensor and the PCB are mounted in the shell. A bearing head of the electromagnetic force sensor extends upward from an upper end portion of the shell. The support ring sheathes the bearing head. The weighing pan component is mounted on the bearing head, with the support ring located between the weighing pan component and the shell. The air baffle ring is disposed around the weighing pan component and located on the support ring. A first airflow channel is formed among the shell, the support ring, and the air baffle ring. At least part of airflow in the shell flows to the outside through the first airflow channel.

First claim

What is claimed is:

1. An integrated high-precision weighing module, comprising:
a shell comprising a housing having an upper end surface provided with a through hole;
an electromagnetic force sensor, mounted in the shell, with a bearing head of the electromagnetic force sensor that extends upward from an upper end portion of the shell through the through hole;
a printed circuit board (PCB), mounted in the shell;
a weighing pan component, mounted on the bearing head;
a support ring that is sheathed over the bearing head and is located between the weighing head component and the shell, the support ring comprising a support plate and a mounting portion that is disposed on the support plate, wherein the support ring is sheathed over the bearing head, in a clearance fit, by means of the mounting portion; and
an air baffle ring, located on the support ring and disposed around the weighing pan component;
wherein a first airflow channel is formed among the shell, the support ring, and the air baffle ring, such that at least a part of the airflow in the shell flows to the outside though the first airflow channel when the integrated high-precision weighing module is powered on;
wherein the support plate is provided with a plurality of air channel holes that surround the mounting portion and are in communication with the through hole, a protrusion that extends upward is arranged in a circle at a periphery of the air channel holes, such that a flow channel is formed between the protrusion and the mounting portion; and
wherein a lower portion of the air baffle ring is in clearance-fit with an upper portion of the support ring to form a first gap channel, and the first airflow channel is formed by the flow channel being in communication with the first gap channel.

2. The weighing module of claim 1 , wherein the weighing pan component comprises a weighing pan support that is mounted on the bearing head, with a weighing pan mounted on the weighing pan support.

3. The weighing module of claim 2 , wherein:
the shell comprises a bottom plate; and
the electromagnetic force sensor and the PCB are mounted on the bottom plate, and the housing, which is connected to the bottom plate, covers the exterior of the electromagnetic force sensor and the PCB.

4. The weighing module of claim 1 , wherein each air channel hole is a slotted hole.

5. The weighing module of claim 1 , wherein the mounting portion comprises:
a first mounting portion, located outside the housing, that extends upward along the support plate; and
a second mounting portion, located inside the housing, that extends downward along the support plate,
wherein an outer diameter of the first mounting portion is greater than an outer diameter of the second mounting portion.

6. The weighing module of claim 5 , wherein:
a second gap channel is formed between the mounting portion and the bearing head;
the air baffle ring is sheathed over the first mounting portion;
a third gap channel is formed between the air baffle ring and the weighing pan component; and
the second gap channel is in communication with the third gap channel to form a second airflow channel.

7. The weighing module of claim 6 , wherein the air baffle ring comprises:
an outer cylindrical ring;
an inner cylindrical ring, arranged concentrically with the outer cylindrical ring; and
an annular plate that connects the inner and outer cylindrical rings, such that an upper cavity and a lower cavity are formed between the inner and outer cylindrical rings, with the first gap channel located in the lower cavity.

8. The weighing module of claim 7 , wherein an outer end portion of the weighing pan is at least partially located in the upper cavity.

9. The weighing module of claim 7 , further comprising:
a plurality of anti-overflow protection holes, located at the lower cavity of the outer cylindrical ring.

10. The weighing module of claim 3 , further comprising:
a heat-insulation plate, provided to isolate the electromagnetic force sensor and the PCB in two independent spaces.

Assignees

• Mettler Toledo Changzhou Prec Instruments Ltd
• Mettler Toledo Changzhou Measurement Technology Ltd
• Mettler Toledo Int Trading Shanghai Co Ltd

Inventors

• Huang Dandan
• Li Xiang
• Zhang Ping
• Cai Jinjie

Classifications

• G01G7/02 Primary

  by electromagnetic action · CPC title

• G01G21/02

  Arrangements of bearings (bearings per se F16C) · CPC title

• G01G21/22

  Weigh pans or other weighing receptacles; Weighing platforms · CPC title

• G01G21/286

  with windshields · CPC title

• G01G23/00

  Auxiliary devices for weighing apparatus · CPC title