At a glance
| Patent number | CN205903203U (application CN201620362461) |
| Type | China utility model (实用新型) - protects product shape and structure |
| Original title | Bathtub (一种浴盆) |
| Patent owner | Nanjing Jiumen Auto-Control Technology Co Ltd |
| Inventors | Sun Rongsheng |
| Filing date | 2016-04-26 |
| Grant date | 2017-01-25 |
| Status (China) | Lapsed - terminated for non-payment of annual fees (recorded 2018-05-15) |
| Patent family | Chinese filings only - no US, European, Japanese, PCT or other filings listed |
| Cited by | 10 later documents |
| Source | Google Patents (search for CN205903203U) |
What the claims cover, in plain language
Claim 1 - a bathtub comprising a shell and a heater arranged inside the shell. The bathtub has an open top and an inner chamber used for accommodating a human foot or hand. It also includes an air extractor (air pump) for evacuating the inner chamber, and a sealing mechanism for sealing the gap between the open top and the human body.
Claim 2 - the bleeding point of the air extractor connects to the inner chamber through an air passage, and the air passage is provided with a valve. Claim 3 - the sealing mechanism includes a flexible membrane and a double buckle. The outside of the flexible membrane is fixed to the outer ring of the bathtub open top, and the inner side is connected with the double buckle. Claim 4 - alternatively, the sealing mechanism is an inflatable airbag fixed at the bathtub open top, with two holes for a foot or hand to stretch into the inner chamber. Claim 5 - the bathtub also has a controller that controls the heater, the pump, and the valve. Claim 6 - the shell is a lagging casing. Claim 7 - the system further includes a pressure sensor, a temperature sensor, and an ozonator connected to the controller. Claim 8 - alternatively, the sealing mechanism is a seal rubber sleeve fixed to the outer ring of the open top, which tightens up after being turned over to seal against the hand or leg.
This is a simplified reading for orientation only. The legal scope is defined by the exact claim wording in the official Chinese document.
What this means for US production
This patent was filed only in China and is lapsed, having been terminated for non-payment of annual fees. It therefore no longer restricts anyone in China. It has no US or other foreign counterpart.
Two points to settle early:
- Other patents may exist. Otivio As holds later US and international patents in this field that cite this document (including WO2019064288A1, USD900996S1, and US10940075B2). Because other companies hold active patents related to vacuum or negative-pressure bathing devices, a freedom-to-operate (FTO) review is necessary before tooling or selling in the US.
- Pressure vessel and electrical safety. Combining a water heater, an air pump, and a sealed chamber requires careful engineering to prevent over-pressurization and electrical hazards. The vacuum levels and structural integrity must be confirmed on prototypes.
Customization and manufacturing
What can be customized
| Area | Options |
|---|---|
| Chamber size | Dimensions to accommodate one foot, both feet, or hands; depth and volume to be confirmed in design |
| Sealing mechanism | Flexible membrane with double buckle, inflatable airbag, or rolled rubber sleeve |
| Shell material | Lagging casing construction; outer finish and insulation thickness set in design |
| Controls | Controller interface, programmable cycle times, target vacuum level, and temperature limits |
| Sensors and add-ons | Pressure sensors, temperature sensors, and ozonators as described in the claims |
| Valve type | Electromagnetic valve specifications, such as the two-position three-way valve mentioned in the text |
Things to plan for (US market)
- UL 1431 (personal hygiene and health care appliances, which covers foot baths) - the heater, pump and controller sit next to water, so leakage current, insulation and dry-heat protection are tested as one appliance.
- FDA device status - the patent links the negative pressure to limb microcirculation. A circulation claim can make the product a medical device that needs FDA classification and establishment registration of the factory; a version sold for relaxation soaking only can follow FDA’s General Wellness guidance. The claim wording decides which route applies.
- Ozone limit (21 CFR 801.415) - if the optional ozonator from claim 7 is fitted, ozone output must stay within the FDA limit for devices.
- FCC Part 15 - the electronic controller and electromagnetic valves must comply with limits for digital devices.
- California Prop 65 - plastics, rubber sleeves, and heating elements must be screened for listed chemicals.
How a project runs
- Inquiry - define the target user (foot vs. hand), preferred sealing method, and feature set.
- Design - engineer the lagging casing, chamber dimensions, air passage routing, and controller logic.
- Prototype - build samples to test the seal integrity under negative pressure, heater performance, and valve response.
- Pilot run - conduct electrical safety testing, pressure cycling endurance tests, and material compatibility checks.
- Production - mold the shell components, assemble the pump, heater, and valve systems, install the controller, and fit the chosen sealing mechanism.
Quantities & timeline
The lagging casing and inner chamber require injection molds or thermoforming dies sized to the chosen capacity. The air pump, electromagnetic valve, and controller are sourced or assembled as electronic sub-systems. Certification testing for electrical and water-heating safety takes significant time before volume production can begin. Send us your target capacity, preferred sealing mechanism, feature requirements, estimated quantity, and destination market and we will reply with options.
Patent drawings
Drawings reproduced from the public patent document for reference.
