Skullhouse Sanitizer

Introduction

Dishwashers were introduced into the domestic world in early 20th century eventually becoming commonplace in domestic residences by 1970. In parallel with the progression of domestic dishwashers, commercial counterparts were also developed for establishments such as hotels and restaurants where larger amount of dishes must be cleaned at a more frequent rate. The commercial counterparts also created products that specialized in certain areas such as sanitation. Sanitizers usually have two different methods to achieve sanitation through the usage of chemical sanitizer, or through booster heaters that provide a high heat rinse usually in 82 Celsius range (180 Fahrenheit). The wash water is heated with an in tank electric heat element, and, depending on the machine, mixed with a cleaning solution.

The main purpose of this device is to be the final step of the dishwashing process. Washing dishes is a cleaning process where food and other materials are removed from a surface, while sanitizing is the process of reducing the number of microorganism on the dishware to a safer level and therefore practicing safe food handling. Improperly cleaning and sanitizing of food contact equipment allows transmission of pathogens to food or the consumer and leads to potential transmission of illnesses.

The focus of this analysis will be on the sanitation feature of this machine. The Hobart LX18 will be the specific sanitizer that we are looking at.

Features

Users: Commercial businesses, higher establishments such as restaurants and hotels, fraternity brothers with dishwashing duties. The users span through a variety of different occupations that could include chefs, janitorial staff, kitchen dishwashers, and MIT students.

Functions:

• Heats up water
• Sprays out hot water up and down the inside of the machine
• Drains water
• Sanitizes dishes

Sanitizer components:

1. Control Panel
1. Extremely minimal user interface with three buttons, two of them being the power buttons, and one function button
1. ON, OFF, and WASH
2. Display
1. Used to show a variety of states that the machine is operating under
1. States include: Wash; Rinse; Temperature (in celcius and Farenheit although theres no way to switch between them), Fill, and Pd (shown below)
3. Rack Shelves
1. Used as the an elevation feature to stop the rack from being submerged into the water or interfering/being in contact with the spinning water
4. Water basin
1. Used to store the water that will be used for the sanitation process
5. Rotating blade with water nozzles
1. Component that is able to distribute water throughout the sanitizer by the utilization of nozzles and high speed rotation by a central axis
2. Utilizes the basin as a source of water for this operation
6. Door
1. Acts as a barrier between the heated water and the user

User Experience

The sanitizer is used 5 times a week, usually by different individuals each day.
I have included to procedures, one of them how the sanitizer should ideally work if streamlined and the second was created by surveying different users and their experiences with the sanitizer

Ideal set of steps to properly use the sanitizer:

1. Turn on sanitizer
2. Manually fill basin with water from a different source (kitchen sink) until Fill notification goes away
3. Load rack filled with plates into the shelves of the sanitizer
4. Press wash
1. Sanitation starts by heating up water to correct temperature
2. Water is sprayed from the rotating fans into the dishes to sanitize
5. Unload Washer

Common steps experienced by users:

1. Turn on sanitizer
2. Manually fill basin with water from a different source (kitchen sink) until Fill notification goes away
1. Water level sensors fails to register the water level
2. Turn off the machine then back on to try to reset (this drains the water in the basin)
3. Manually fill basin again
3. Load rack filled with plates into the shelves of the sanitizer
4. Press wash
1. Sanitation should start by heating up water to correct temperature but on occasion water is sprayed wihtout the correct temperature
2. Fill up basin again as the water has been used and press wash again (some people have reported doing this 3-4 times until the water reaches sanitation temperature levels)
5. Unload Washer

Pros and Cons

Based off personal user experience, and interviews with peers about their experience with the sanitizer here are the pros and cons

Pros:

• Sanitizes the dishes with heat and therefore reduces chances to spread illnesses
• Dries faster than air drying due to the higher temperature of water
• No chemicals need to be used or purchased to sanitize the dishware
• Does not damage flatware and plastics

Cons:

• No indication for water heating up
• No water fill level line so must rely on the fill level sensor, sometimes causing it to overflow. Note: We currently fill the basin until it slightly overflows as a guarantee that the minimum water level is reached
• Counterintuitive as the action button is labeled wash but instead sanitizes
• Requires to manually fill the basin with water. Note: We fill up other containers from the near by sink and dump them into the basin
• No possibility for troubleshooting
• No locking mechanism for the door so it can be opened in the middle of a session
• Door slams down when opened
• On occasion the machine rinses the dishes with the water instead of sanitizing
• After sanitizing properly, there is a large amount of steam that is released when opening
• Symbols appear on the display without any context of what they could mean

Improvements

There are many ways to improve on the desing, many of them include additions to the user interface but some mechanical changes would also improve the user experinece with the sanitizer

Changes

• The addition of dampers/springs on the side will create ease of opening, avoiding and preventing sudden falls of the door
• The addition of buttons create for ease of selection in the actions of the sanitizer, avoiding confusion of what the sanitizer will do next. The PreHeat button also allows for set up of the sanitizer so the user can prepare the rack of dishware while it is warming up
• The display has been slightly changed adding an option for sanitizing, so that the user would know what process its currently undergoing.
• Physical fill levels will act as a indicators for necessary water levels instead of relying on slow updating sensors
• A guard for water spillage is would be added to prevent overflowing and backsplash when water is added. This guard would also act as additional safety, preventing large wet areas near the sanitizer that one could slip on.
• A pipe connected to plumbing system would facilitate automatic filling for the sanitizer, disposing of the need to manually fill it with adhoc devices such as pitchers.
• (Not shown) A locking mechanism would allow for reduced chance of burns from steam and water. It would also prevent the possibility of a user opening the sanitizer mid cycle.
• Embedded LEDs in the user interface will act as feedback for the user in what state/action the sanitizer is in, reducing confusion of what the product is doing at the time. It would also reduce the clutter that the display would have.