Filtration vs drag
When picking out a new water pipe, a key consideration is how much diffusion, or filtration, you want in contrast to how much resistance, or drag, you can accept. Generally, the better filtered of a hit you are receiving, the more drag there will be. However, resistance can be generated in many ways which do not increase diffusion, so that is not to say more resistance means there is more diffusion. This can be especially important if you have any health problems that can add to the difficulty of dealing with the resistance. In this article, we’ll talk about important considerations when picking out a new water pipe.
What is diffusion?
Diffusion occurs as the smoke goes through the water, and the water filters out some of the tars and larger particles. The more contact between the smoke and water, the more the smoke will be filtered. Therefore, optimal diffusion is achieved by an even distribution of small bubbles. This will produce the most surface area for the smoke to interact with. Cooling the smoke with water also relies upon the amount of contact between the smoke and water, so in a two-fold benefit, this will simultaneously cool the smoke better.
What causes drag?
Any time you add an extra layer of water filtration you are going to be adding some amount of drag to the piece. However, this adds much less resistance than some other common causes that can be avoided in manufacturing.
One factor contributing to resistance is the diameter of the tubes the air travels through, and not just the width of the tubes but the width of any connections. The smaller the diameter, the less air that can be pulled through at once. This will create a feeling of drag, so any pinch point can drastically increase the drag. This is something to look for in any corners or curves in a piece to ensure that the diameter isn’t drastically decreased. This is why most TAG pieces bend into the percolator or have an elbow protruding rather just than a sharp 90° corner which can cut down the inner diameter.
Some poorly designed percolators can also create unnecessary drag. If, for instance, the holes the smoke travels through are too small. This can cause more resistance without increasing the filtration. Conversely, if the holes are too large or uneven, it is likely not all the holes will be used in filtering the smoke. This can feel like there is less drag, especially after you pull out the bowl because there will be less resistance and all holes are likely to fire then. However, it will dramatically decrease the amount of filtration since the smoke itself will have less contact with the water.
Each time you add an extra layer of percolation this increases the drag to an extent since there is more resistance in water than air (think of moving in a pool). Although, some types of percolators do add more drag than others even when properly manufactured and designed. This tends to occur in percolators with many small holes which produce many small bubbles. In some cases, there can be so many bubbles that they can also add to the resistance. This tends to be seen in percolators such as fritted and netted discs, which consequently produce some of the best filtered hits. It should be noted though that most of the resistance still comes from the area the smoke has to travel through at any given point, and because the holes are larger in a netted disc the air flow will be less restricted in comparison to fritted discs.
Picking your piece
While some percolators do generate more drag than others, there is much that can be done to reduce drag and achieve optimal diffusion. First, pay attention to the characteristics of percolators discussed above. Are the holes evenly distributed? Are the holes large enough or are there enough small holes to not restrict the airflow? Think of the total area the smoke has to travel through at the percolator. Are they so large that not all the holes actually filter the smoke? It is easiest to answer by watching a video if it is available, but you can also refer to the images of the piece. TAG pays special attention to these details to engineer water pipes that achieve optimal diffusion with minimal drag.
When asking yourself if you should add an extra ash catcher or choosing between a netted disc or showerhead percolator, it really depends what is most important to you: the smoothest hit possible or the least resistance. Both have their advantages and should be considered to optimize your experience, but the weight placed on each is up to you. So, try out a variety of options and see what you prefer. There’s nothing wrong with having a few around to suit your mood on any given day!
Photo Credit: www.nuclear-power.net