SCALE

Posted on January 20, 2022 by george

die cast machines evolved from steam engines

High pressure aluminum die casting is a thermal process. Our melt furnaces add a lot of heat to make aluminum molten. During each casting cycle this heat is transferred to the casting die solidifying a casting. In each casting cycle the heat added to the casting die must be removed so that the die is ready for the next casting event. Evaporation of water is the most common heat removal method. Die spray systems and cooling towers remove this heat Because the thermal conductivity of die steel is low the majority of the heat is removed by die spray when it is used. This article is focusing on the heat removed by the thermal passages within the die

Fluids flowing through the thermal passages in the die remove heat. Cooling tower water is the most commonly used fluid because water has a high heat transfer capability. Other fluids used are hot oil or compressed air. The properties of aluminum castings are enhanced by rapid cooling. In many casting dies careful placement of internal thermal cooling passages is needed to create quality castings. These dies only produce quality castings when proper heat transfer flow occurs through clean passages.

Cooling tower water has some disadvantages. The evaporative cooling tower concentrates minerals in the water. These minerals then deposit within the casting die as scale. I always use individual return lines so that a once a shift check for plugged thermal passages can occur. Visual management is better than nothing, but it can result in whole shift of scrap castings. No heat removal is occurring if the passage is plugged with scale. It is even more frustrating when you need to pull the die once per shift to clean out scale build up -happens when boiling occurs in the passage.

The emergence of structural castings and 3D printed conformal cooled inserts is causing a rethink. Some players are trying to set up a HPDC process more like injection molding. ( The die temperature is totally set by the TCU (thermal control unit) More internal die cooling is designed in to eliminate the evaporative spray cooling. As with any new technology being developed there are growing pains. Scale build up being one of them. Starting my career as a piping engineer I suspect the solution for scale build up will come from our “Engineering” roots. Engineers are the people who ran the steam locomotives. Eliminating scale mineral buildup is a lot easier if you circulate water that does not contain them. Sounds like boiler feed water .https://en.wikipedia.org/wiki/Boiler_feedwater

Having made a few million aluminum castings without using evaporative spray cooling, I can report some benefits. The casting plant is no longer a steam bath in the summer. Spray lube induced porosity problems disappear. Beyond that there is a fresh water shortage .https://www.bbc.com/future/article/20170412-is-the-world-running-out-of-fresh-water

Perfect Storm

Posted on February 21, 2021 by george

Propane powered windmills protect vineyards and orchards

Weather events like the recent storms that caused the recent power outages in Texas, show the limits of our electric power system. The current power interconnect grind is only able to carry 5% of the power that we use. This means that the power you use is generated locally. When a town like Houston is hit with a cold weather event that causes a spike in electric demand a 5% capacity interconnect grid will not save them. This is why you see propane powered frost protection in more northern areas. They will work when an ice storm kills power from the grid. Electrically heated hot houses like you see in Texas are doomed to not provide protection when a winter storm descends.

local electric storage will be a part of every electric refueling station

.We wish to double the amount of electric power we wish to purchase from our electric power grid to power electric vehicles. While this is a good thing for climate change, it causes other problems. Currently the pipe line system delivers the lions share of the vehicle fuel we use. Each gas stations stores a few days supply. An electric grid that currently only carries 5% of what we use will be severely overtaxed if we double our usage. Beyond that no one wants a high tension transmission line in their back yard. The near term solutions will involve continuously transmitting at capacity by adding energy storage at both ends. Home vehicle recharging equipment will simply not work when the grid is overstressed to the dismay of individual users.

20/20 Foresight

Posted on October 23, 2019 by george

It is very easy to focus on the familiar places that you have already been. Yes there were challenges back then that caused us to struggle. However from our current vantage point we know how to deal with those struggles. Looking out the front window into the future is a bit scarier. We cannot rely on 20/20 hindsight.

An election is a time when attention is paid to the direction that we are headed. In Canada one of the issues is a new cross country pipeline. Looking out the back window at the 1,000,000 dollar a day cost to complete the Alaska pipeline, we are aware that pipelines are costly investments. However oil that is in the ground does not fill our gas tanks.

Do you see the oil pipeline or the electric power lines?
Both transport the energy that you use.

Now that we have the results of Canadian election, it is not surprising that whole provinces voted conservative as a block. They wish to believe that the 20/20 hindsight formula of building more pipelines will solve their economic problems. The rest of the country is not so sure. Looking with 20/20 foresight the prairies are blessed with enough wind power to satisfy our energy needs for a long time. Rolling Thunder, the largest wind power project to date is a good example $800,000,000 of the billion total cost was spent on the transmission lines with only $200 million on the windmills themselves. With the closure of coal fired power plants, the consumers in eastern Canada could really use affordable electricity. With 20/20 foresight our efforts should be focused on inventing and installing cost effective cross country electric transmission. As we look to powering the electric vehicles that we all desire, 20/20 foresight suggest that new infrastructure investment should be aimed at transporting the type of energy that we want.

Fill ‘ER Up

Posted on March 2, 2019 by george

How long do you want to spend refilling your vehicle with energy? Most of us grew up driving gasoline powered vehicles that refill in about 10 minutes. This experience sets our notion of how long this should take. None of us even think about the investment in infrastructure that makes that possible.

Closest in the chain is the investment made by the gas station owner in tank capacity to supply their customers with energy for two days. It takes a scare like a “gas shortage” for the average public to even consider this fact. When a “gas shortage” with the long line at the pumps occurs, what is really happening is every one is topping up their gas tanks. The amount of energy required to top up everyone’s tank is greater than the 2 days of supply at the stations.

Pipelines and gasoline delivery infrastructure blankets the country

The gasoline delivery truck is refilled from a local tank farm that is fed by a pipeline, tanker truck, rail tankcar, supertanker etc. transport system that has been put in place over the last century. It is not surprising that none of us can remember a time when it was not there.

Electric feed to many gas stations are the size of your home feed

Electric utilities provide power to virtually all stations. They all use electricity to run the lights and the signs. As you can see in the picture, the size of the wires matches the size that feeds your house.

A USB cord does a great job of supplying energy to your smart phone. You will wait a long time for dinner if you try to use it to power your electric stove. Obviously the point that I am trying to make is that most existing stations are set up to deliver gasoline, not electricity. Even though they happen to have an electric power feed it is way too small for them to convert to supplying electric vehicles.

The US has some infrastructure for delivering electricity. The Grid as it exists today was set up so that the individual electrical producers could help each other at times of high demand. Accordingly it can transport about 5% of the power that we use. This lack of electrical transport capacity is before we try to add the additional requirement of powering our vehicles. Contrast this with the gasoline transport system that can deliver 100% of that type of energy. As we try to migrate to electrical powered vehicles a few pieces of infastructure are missing.

Energy stations will need to have 2 days worth of usage stored on site. We as consumers like to travel en masse on holiday weekends. Peak demand spikes are best handled by local inventory. I can picture notable power blackouts the first time a summer power grid overload due to hot weather occurs before the 4 of July holiday weekend. It will be hard to chose between staying cool while packing and filling up the car for the trip to the beach.

The center of the US is sparsely populated

Solving the lack of electrical transmission capacity will take greater creativity. I can picture a time in the near future where visually looking for landmarks like windmills or solar farms will be how you guide yourself toward your next refill. It does not make sense to spend money on transport when the electricity can be renewably generated locally.

Getting back to the first question. This EV will take all day to refill with energy based on the size of the charging wire. That is Ok when you have the time to wait. Changing to a larger size wire only fixes part of the issue. Using a fire hose to fill your swimming pool is not faster if it is still hooked up to your back faucet. We are all considering switching to electric vehicles. None of us are sure when there will be enough infrastructure to support our actual needs.

Test Drive

Posted on December 28, 2016 by george

Car on test track

As a mechanical engineer my focus is usually on mechanical devices. It is necessary
to remind myself that a test drive is usually needed to discover how the rest of the population reacts to those same devices. Surprise! Surprise! most people are not naturally mechanically inclined. This becomes obvious when the general public participates in test drives. The software industry discovered the same truth. Beta testing with real users is the way they arrange test drives. High powered artificial intelligence built into programs is of little use if you cannot get the friggin! computer to turn on.

The simple Human Machine Interface action of pressing a button becomes a nightmare if there are too many of them

As Moore’s law increases the number of transistors within the computers that we use, the engineers, business owners and, investors who invent the devices and programs that use this horsepower are very tempted to overwhelm the buying users with a multitude of blinking and flashing lights to herald the latest and greatest. I admit that when I was inventing the Chrysler Mini Van, it was very frustrating that the general public did not recognize how great it was while I was designing it. That public recognition became even more important when we first tried to sell some. I understand why the designer of my electric kettle wants to highlight his addition of a digital temperature display into the device. Rubbing it in my face by incorporating a seemingly random sequence of four button pushes to turn the device on, spoiled my perception of the benefit.

The Mustang became a sports car for the masses

The throttle pedal is one of the key interfaces between the driver and the vehicle. The Mustang succeeded because of an invisible triumph in this area by the Mustang design engineers. Their throttle linkage made the Ford Comet compact car chassis feel like a sports car. As I launch a new generation electric vehicles, similar attention is being applied to the throttle. The latest generation dual hall effect encoders are being used to create a tight linkage between the vehicle and the operator commands. Embedded computer intelligence is being programmed to achieve the “feel” of expensive mechanical links. User invisibility is still the key. We still need to wait until the vehicle users test drive our improvements before we can expect recognition. I have seen this before with the Minivan

AC Induction

Posted on July 24, 2016 by george

AC motor cut away by SJ De Waard

I was a part of a discussion after a cost improvement session with one of my clients in 2000. This OEM supplier designed and made starter motors and alternators primarily for General motors. Due to the fact that I had invented a few actionable cost improvements, during the session I was asked what would be a long term cost improvement game plan. I suggested that they eliminate the starter motor to save cost. This suggestion was received with surprise, in that starter motors generated half of their sales. At that time the Prius had just come out. In this hybrid, an additional motor / generator was added to the starter motor and alternator that were already a part of the vehicle drive train. An average US passenger vehicle only uses 500 gallons of fuel per year. Even at $3.00 per gallon this only adds up to $1500 per year. Most people cannot justify a doubled vehicle purchase price, because it is both an electric vehicle and a gasoline vehicle, just to save fuel use.

Prius by JBleeker

Here we are in 2016, what has changed? The big item is power electronics. Back in 2000, some of my best friends made a good living simply replacing the power transistors in the Variable Frequency Drives (VFD) used to run AC induction motors. The best we had simply could not handle summer heat. The Prius had three separate motors simply to avoid using the unreliable transistors. Advancements in power transistors changed that equation starting about 2006. Certain visionaries like Elon Musk translated this technology advancement into a new generation of electric vehicle. Fundamental technology improvements are not just limited to high dollar luxury cars. Delphi has just introduced a 48 volt combo starter motor, alternator and hybrid drive motor / generator which is a single AC induction motor as I had suggested back in 2000. In today’s lean fashion, an affordable vehicle is the result of using fewer components instead of adding more.
AC induction motors are also coming to industrial vehicles. In the new generation warehouse electric vehicles that I am designing, an AC induction motor will be standard. The new generation of power electronics and control strategies and AC induction motors are giving us 60% more run time.

There just might be gold at the end of the rainbow

The range anxiety that is a part of using a personal electric vehicle also applies to warehouse vehicles. Many of our users are pleased that the extra range made possible by using AC induction motors lets them use the vehicle for a shift or two before recharging.

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