project number: p17325

Multidisciplinary Senior Design Conference Kate Gleason College of Engineering

Rochester Institute of Technology Rochester, New York 14623

Copyright © 2017 Rochester Institute of Technology

Project Number: P17325

AUTOMATED KEG WASHER

Brian Bradford, Katie Brinskele, Ahmed Al Ebri, Brandon Kulzer, Eric Roth, John Rueckel

ABSTRACT

Multidisciplinary Senior Design at RIT partnered with two RIT alumni who opened their own brewery outside of

Binghamton, NY. In the planning process for the brewery development, one of the major pieces of equipment

identified to benefit their company was an automated keg washer. The purpose of this system is to clean all dirty kegs

using four cycles. The first cycle is rinsing the keg, followed by a heated cleaning cycle, a critical sanitation cycle and

closing with an air purge cycle. These cycles ensure that the kegs are free of microbes and then replenished with CO2

so that all beer being delivered to customers is fresh and sanitary.

Team P17325 was given the task of developing a fully automated single keg washer with all the major functions

of a commercial model at a fraction of the cost. By the end of two terms, the team delivered a fully automated and

functional dual keg washer to the customers that can complete all four major cleaning cycles at a cycle time of 4

minutes for two kegs. The keg washer was built at a competing cost to other commercial washers, which include equal

functionality. This paper will further address how the team built the system to meet the needs of the customer.

Project P17325

BACKGROUND

Beer Tree Brew Co. is a small Farm Brewery located in Port Crane, NY. The founders of this company are

Brendan and Chris, two RIT Alumni. After leaving the college, they pursued careers in engineering, during which

they decided they would also invest in their passion, craft beer. The love for craft beer started when Brendan was on

co-op in California and spent a large amount of his free time traveling to craft breweries. After that co-op, Brendan

wrote up a business plan for his own brewery, but it wasn’t until 2014 that it seemed like he could turn that plan into

a reality. When his father in law opened Willet Hop and Grain in Willet NY, Brendan

spent countless hours testing out new recipes on the farm. After some time, this passion

was shared with his brother in law, Chris. They spent every weekend brewing until

they had an approved business plan. That business plan was the foundation of Beer

Tree Brew Co., the beautiful brewery that opened its doors on October 20, 2017.

The focus of the company is to provide customers with fresh beer produced with

local ingredients. To ensure that customers are receiving high quality product, the

brewery will need to invest in reliable equipment to sanitize the kegs that will be cycled

throughout the facility to supply beer to the taproom. The main kegs used in the

brewery are ½ barrel kegs and have a capacity of 15.5 gallons, which is equivalent to about 165 12 oz. pours. This

means that every 165 servings, the employees will need to wash a keg. On opening weekend, the brewery had a turnout

of about 3,600 people. If each of those individuals consumed a single beer, the brewery would have had 22 empty

kegs by the end of the weekend. With the process they had at the time, manually washing all the kegs would take 11

hours of continuous work. Team P17325 aimed to reduce that time to 4 hours with their improved design.

PROCESS AND METHODOLOGY

DMAIC: Define

The define phases consisted of outlining

the scope of the project, determining team

roles and developing an initial plan. The

initial requirements were gathered by

using two tools. The first tool is the

Project Readiness Package compiled by

the customers prior to the start of the term,

which outlines the purpose of the project

and high-level details of their desires. The

second tool the team used was an initial

customer meeting. This meeting took

place within the first couple weeks to

clarify and solidify the requirements and

desires of the customer and decide further

means of communication throughout the

phases of the project. From these, the team

defined and documented the engineering

requirements and customer needs. Some

of the most important items outlined

included features to ensure the safety of

the user (emergency stop buttons), single

phase to power entire unit, can accommodate ½, ¼ and 1/6 kegs, must complete all operations in the cleaning process,

must fit the 4.5’ by 3’ footprint and must be corrosion proof. The biggest constraints of the project are the budget

(originally set at $2500), the dimensions, mobility, and knowing that visual inspections will not be able to be

performed once in the brewery.


DMAIC: Measure

The next steps were to define the key performance indicators (KPI) of the system. These are the items that will

show the customer that the process is working the way it is supposed to. The keg washer has four specified cycles that

it must run through to satisfy the requirements of the product. These cycles are the rinse, clean, sanitize and pressurize

cycles. In addition to the functionality of the system, the product must retain its corrosion proof requirements as well

as ensuring the electronics are enclosed in a sealed waterproof container, so nothing can be damaged. The final

measurement is to confidently say each keg is properly cleaned by the end of the cycles. Because the kegs cannot be

deconstructed to check this, the team will need to find alternative ways to test during the build phase. The team will

run tests using a “test keg” that will have a cut out in the wall to allow the inside to be visible to the team.

DMAIC: Analyze

Given this information, the next steps for the team included evaluating current commercial keg washers and

outlining how the final product will size up to the competition. Current products on the market come equipped with

various capabilities ranging from manual single keg to semi-automated to fully-automated and dual keg. These styles

also range in price. The lower end of manual and single keg washers can cost as little as $500, but these models are

limited in features and capabilities. The upper end of automated keg washers can cost around $15,000 for a dual keg

washer. The team researched multiple different models through their home sites to quantitatively qualify them against

the others. The information that the team was interested in comparing were the dimensions, capabilities, washing

speed, cost, options and requirements.

Global Stainless Systems [1] sells a semi-automatic keg washer that can clean 20 kegs per hour. This model

requires 60 psi for water as well as 30 psi for CO2. The electricity requirement is 220V 3-phase 30A. To obtain the

price for this keg the company required a legitimate customer to call for a quote, but online users [2] quoted the system

in the $8,000 range. Noble Keg Washers [3] sells a single head washer that can clean 24 kegs per hour at a cost of

$5,600. This model requires 60 psi for water as well as 20 psi for CO2. The electricity requirement is 120V, 13-20A.

Finally, a third model that the team benchmarked came from Premier Stainless Systems [4], selling a two-station semi-

automated keg washer. This model is sold for $14,950 and can clean 24 kegs per hour. This model requires 60 psi for

water as well as 45-60 psi for CO2. The electricity requirement is single phase. From these models the team specified

how theirs would compare to the competition. With these models in mind, the team set out to build a two-station semi-

automated keg washer that can clean a minimum of 6 kegs per hour at a cost of $4,500. This model will require 30-

80 psi for water as well as 10 psi for CO2 and the electricity needs to be single phase. Compared to other dual keg

washers, the result will be a fraction of the cost meeting the larger scope of the project.

DMAIC: Implement

The result of these tools was a final design that best

fit the criteria determined by the requirements of both the

customer and the team. The final concept is a dual keg

washer capable of cleaning 30 kegs per hour without the

factor of changeover time. The washer is fully automated

and equipped with an aesthetically pleasing user

interface. There are various safety features extended

beyond the requirements and needs of the customer.

Finally, the design is comprised of stainless steel and

watertight electrical enclosures to ensure the longest

lifespan possible. The following information documents

the specifics of the design and rational for the team’s

decisions.

The image to the right is an initial design the team

formed with all features necessary to meet the customer

needs. Modifications were made after benchmarking to

allow for dual keg capability.

Project P17325

The frame of the structure is formed with stainless steel to ensure a corrosion proof build since the process will

involve the movement of various liquids. It is composed of 1” x 1”, 1/8” thick stainless-steel tube stock. This is TIG

welded according to the engineering drawing below. The structure is supported by load-bearing rubber casters with

locking capability to provide for a mobile platform. Plates were constructed from 5/16” thick stainless steel and are

being used as mounting points for the plumbing manifolds. Additionally, the electrical components are assembled

within waterproof containers and

mounted to the remaining plates on

the sides of the structure.

The keg washer is run using an

AMT Stainless Steel Straight

Centrifugal Pump (qualified using the

performance chart below), which

provides the required pressure to

allow for adequate fluid flow within

the system. Steel-reinforced, food

grade rubber tubing transports the

water, air, CO2, sanitizer (Acid

number 6) and solution (StarSan)

throughout the system to the dirty

kegs. The StarSan and Acid number 6

will be housed in two used kegs that

were manipulated to run tubing for the

system and hold the heating element.

The mechanical drawing for these

modifications is seen below. To

automate the entire system, multiple

DudaDiesel 2-way solenoid valves are

opened or closed electronically to

direct the flow of specific fluids. The sanitizer and solution can be reused as directed by the manufacturer for a specific

amount of washes and will be replaced by the customer when necessary.

Multiple cycles of fluids take place throughout the cleaning process. The cycle is as follows: hot water rinse, air

purge, Acid number 6 rinse, air purge, StarSan rinse, air purge, and CO2 pressurization. The cycle is sufficient to

clean both kegs, and can be customized for several situations, such as including an additional rinse cycle or neglecting

an air purge.


The electrical engineers worked on designing the necessary system to control the keg washer and provide the user

with an aesthetically pleasing interface that was easy to use. The team identified that these components should be long

lasting, robust and readily available. A programmable logic controller (PLC) is used to control the system. These are

widely used in manufacturing environments because of their rugged design and ease of programmability. To interact

with the PLC, a human machine interface (HMI) was chosen. The HMI is an industrialized user interface that allows

operators to control the machine and provides a pathway for the machine to send useful information to the operator.

After identifying a PLC to be used, specific input/output (I/O) cards were identified. These are as follows:

• Digital Outputs: 8 solenoids, Pump Motor, Heater

• Digital Inputs: ESTOP, Float Switch

• Analog Outputs: None

• Analog Inputs: Temperature Sensor, Pressure Sensor

After the components controlled by the PLC had been identified, it was necessary to select supplementary

electronic components to ensure the PLC could drive the high current/voltage outputs and ensure the electrical design

was safe for use. A 4500W 240VAC heating element will heat the caustic container to the desired setpoint. With this

heating element, it will take approximately 40 minutes to change the temperature by 70°F. This was deemed an

acceptable amount of time when factoring in the amount of current needed to drive the 4500W heating element. This

equates to 18.75 A and fused at 25A for safety.

Two solid state relays were picked to drive each leg of the 240VAC to the heater. Solid state relays were chosen

over mechanical relays because of the constant on/off switch movement to control the temperature. Each solenoid is

controlled using 120VAC. The mechanical

relays are used to provide the necessary power

when 24VDC is applied to the coil of the relay.

Six of the solenoids draw approximately 0.23A

each while the others draw 0.12A each.

The pump motor is controlled using a

contractor. The contractor uses 120VAC on the

coil side to switch 120VAC to each leg of the

240VAC motor. Because the PLC outputs are

low voltage and low current, an additional

electromechanical relay is used to provide

120VAC to the coil of the contractor. When the

ESTOP button is pressed it breaks the 24VDC

supplied to the electromechanical relay and the

pump will shut down. The pump motor draws 4

full load amps at 240VAC. To supply the

24VDC to the sensors, PLC and coil of

electromechanical relays a power supply is used.

The load of these components was calculated to

be approximately 2A and therefore a 2.5A power

supply was chosen. The 24VDC is fused at 5A

for safety. The power supply draws 1A at

240VAC.

Summing together the total current consumption at full load results in a current of 25.37A. National Electric Code

requires that circuits be sized for 100 percent of the non-continuous load plus 125 percent of the continuous load and

the electrical system had to be protected for 30A, fusing each hot leg of the 240VAC.

State Outputs Description

0 None Wait for start and system to be ready

10 Air blow Sol, Drain Sol Wait for pressure sensor to be below X PSI

20 Drain Sol Wait X Seconds

25 Drain Sol, Hot water Sol Wait X Seconds

30 Hot water Sol, Drain Sol, Pump Hot water rinse for X seconds




70 Castic tank sol IN, Caustic tank sol OUT Wait X Seconds

80 Pump, Castic tank sol IN, Caustic tank sol OUT Run Caustic Solution

90 Castic tank sol IN, Caustic tank sol OUT Wait X Seconds

100 Caustic tank sol OUT Wait X Seconds

110 Caustic tank sol OUT, Air blow sol Wait for pressure sensor to be below X PSI

120 Caustic tank sol OUT Wait X Seconds

125 Drain Sol, Hot water Sol Wait X Seconds

130 Hot water Sol, Drain Sol, Pump Hot water rinse for X seconds




170 Sanitizer tank sol IN, Sanitizer tank sol OUT Wait X Seconds

180

Pump, Sanitizer tank sol IN, Sanitizer tank sol

OUT Run Sanitizer Solution

190 Sanitizer tank sol IN, Sanitizer tank sol OUT Wait X Seconds

200 Sanitizer tank sol OUT Wait X Seconds

210 Sanitizer tank sol OUT, Air blow sol Wait for pressure sensor to be below X PSI

220 Sanitizer tank sol OUT Wait X Seconds

230 Drain Sol, CO2 sol Wait X Seconds

240 CO2 sol Wait for pressure sensor to be above X PSI

States of Automated Keg Washer Program

Project P17325

The programming of the PLC was done using CLICK programming software. A method called state logic was

used to program the PLC. This method steps through the program sequentially making an intuitive program. State

logic allows for our customer to easily troubleshoot and make changes to code. The above table gives the states of the

automated keg washer program. The states in the table bring the machine through a rinse cycle, heated cleaning cycle,

sanitation cycle and purge cycle.

Alarms are programmed in the PLC to shut down the system if any unsafe condition existed. For example, an

alarm would be present if the ESTOP was pressed, caustic tank level dropped below the float switch, caustic

temperature exceeded a high setpoint, etc. The PLC was programmed so that after the alarm is cleared the system

operator is given the choice whether to restart the current cycle or proceed from the beginning of the rinse cycle.

Restarting the current cycle can reduce waste of sanitizer and caustic

solutions if the machine was in the wash or sanitize cycles before the alarm

occurred.

The HMI was programmed with the system operators in mind. The

designed HMI gives the operator the ability to start, pause, and stop the

machine. Operators can see alarms, current machine states while running

(shown in the image to the right) and are given access to heater controls

(on/off). Engineers and machine operators are differentiated in the HMI. In

that, a debug menu is password protected allowing engineers to manually

toggle valves, change setpoints, trend caustic temperature and change PID

parameters.

DMAIC: Control

To qualify the product for the customer, there are multiple factors that need to be verified and validated against

the engineering requirements. The subsystems and systems tested included the fluid flow of the system using the pump

purchased and a prototype structure followed by the functionality of the heating element and time to heat the fluid

tank to 140 degrees Fahrenheit. After these tests, the team tested the functionality of the electrical controls and solenoid

valves. After this test is complete, the team can complete assembly and test the system for full functionality to ensure

it can complete the cleaning cycle.

To test the fluid flow of the system, the team assembled a prototype wood structure with temporary manual

manifolds and tubing to connect all components. Ten trials were run to gain the time to fill a 5-gallon tank. Because

the test resulted in consistent times for all trials, no additional testing was found to be necessary. From these tests, the

team found that the fluid flow runs through the system at a rate of 5 gallons per minute, which is acceptable against

the engineering standards. To test the heating element, the team ran 5 trials to determine the time required to bring the

fluid in the tank to 140 degrees, which is recorded using a temperature gauge. The result of this was an approximate

40 minutes to heat the fluid. This was within the expected range of time and will be executed at the beginning of each

work day before the brewery opens to the customers. The system can then be used consecutively throughout the day

without further heating. For the electrical controls and solenoid valves, the system needed to prove that it could be

manually commanded to complete the functions necessary such as opening and closing solenoid valves. Each

command was run at least 5 times to ensure success. There were no problems seen in this test, so the team was able to

move onto testing the full assembly for completion of the cleaning process.

During the test phase of the system, backflow was observed and created problems for the system. A professional

was consulted, and a solution was developed. To counter the problem, check valves were purchased along with a small

solenoid. With the check valves regulating back flow, the extra solenoid allows for the pump to prime in the initial

phases before the air is opened among the solenoids. After these components were implemented, the team ran

approximately 8 trials to test the system. All cycles were run to completion with the acceptation of one alarm, which

notified the team of low fluid in one of the tanks. This alarm was expected and appropriate and showed the

functionality of the safety features set in place. The final cycle time recorded for the process was 4 minutes for 2 kegs,

giving the system a capability of 30 kegs per hour without changeover time. The customer was very satisfied with

these results and arranged to pick up the product following the closure of documentation.


CONCLUSIONS AND RECOMMENDATIONS

The total cost of the product came to $4,532.50. This

was deemed a positive result when looking back at the

original benchmarking completed by the team. The keg

washer has dual-keg washer capability with a capacity of

30 kegs per hour. This is comparable to the Premier

Stainless Systems model, which is sold at a cost of $14,950.

The total cost breakdown for the system was broken down

by major system to provide a more efficient means of

tracking. The break down included electrical, structure,

pump and couplers, containers, prototype and fluid flow.

This cost breakdown is located to the right. The final design

was an aesthetically pleasing system that the customer is excited to implement in the brewery. The images of the

system are located below (left image: back view, right image: front view).

Throughout the course of this project, the team encountered some problems that we believe could benefit future

teams as some lessons learned. Initially, the project plan allowed for three weeks of slack time. Some activities were

underestimated during the project planning. The welding of the structure was completed through the employees of the

Brinkman lab. Although the estimated time to complete the welding was two weeks, this did not mean that the welder

could fit all the welding into his schedule in that time. The total time came to approximately 3 and a half weeks.

Another factor that went left unconsidered was the shipping time of parts. Some companies had a longer leadtime and

increased pricing due to implications from a recent storm. This increased the budget from the original estimation,

which is something teams need to consider in long term projects such as this.

Project P17325

Prototyping is another costly investment as it is not usually something that can be carried over into the final

structure. Approximately $100 from the team’s budget went to creating a prototype structure to qualify the pump. If

the team waited until building the final structure to qualify the pump, they could have saved that cost for other future

components. This was a risk the team considered, and decided that a prototype would be more beneficial as it would

help detect problems with the pump, a major and expensive component of the project, early on. It also gave the team

a gauge for what the maximum footprint of the structure could be and how they could minimize it to allow for the

minimization of steel, a very expensive material.

Overall, this project was very successful, and the team was able to work together and utilize their strengths to

provide the customer with the highest quality product possible. This provided each member with the valuable

experience of being exposed to a long-term project and managing the responsibilities of an important job around the

other responsibilities in their career. We are very happy to have worked with Beer Tree Brew Co. and know that our

product will be apart of their brewery for years to come.

REFERENCES

[1] Global Stainless System. (2017). Shop Keg Washer. Retrieved from http://www.globalstainlesssystems.com/dual-

head-keg-washer

[2] KINNEK. (2017). Compare Quotes From Top Keg Washer Suppliers. Retrieved from

https://www.kinnek.com/products/keg_washers

[3] Noble Keg Washers. (2017). Shop Keg Washers. Retrieved from http://www.noblekegwashers.com/index-3.html

[4] Premier Stainless Systems. (2017). Shop Multiple Station Keg Washers. Retrieved from

http://www.premierstainless.com/multiple-station-keg-washers

ACKNOWLEDGMENTS The Automated Keg Washer Team would like to thank and acknowledge our sponsors Chuck Rhoades,

Brendan Harder, and Chris Rhoades, the owners of Beer Tree Brew Co. for funding the project and providing us with

this experience to grow as engineers and apply our skills while providing them with what we hope to be a great product

for their business. We would also like to thank Professor George Slack of the Electrical Engineering program at RIT

for all his guidance through the project process and Robert Kraynik of the Brinkman Lab at RIT for all his help with

welding and construction of our final project. The keg washer could not have been completed without any of these

individuals. Finally, we would like to thank Swiftwater Brewery for providing us with a demonstration of their manual

keg washer built by the owners itself.

project number: p17325

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