The cleaning of tanks and vessels is often an overlooked source of inefficiency in the production process. As an "unglamorous" and non-core procedure the true price of cleaning is frequently neglected. However, with some believed significant efficiency gains can be achieved. As will be observed these efficiencies come from a mixture of the 4 essential components of the cleaning process i.e. time, high temperature, mechanical action and chemical substance action. The focus of this article is on how quick wins may be accomplished by improving the mechanical action element of the cleaning mix.
The balancing act - Any cleaning application has four parts that contribute towards effective cleaning.
1- Time. The much longer the washing if performed the NJ office cleaning Cleaning World Inc greater the cleaning.
2- Chemicals. This is actually the dissolving effect of chemical cleaning fluids including water.
3- Mechanical action. This is physical action of the cleaning spray to dislodge residue.
4- Heat. Generally the hotter the washing liquid the better the washing action.
Increasing these 4 elements will improve overall washing but you will have a cost associated with each. The price of each of these elements will differ based on program and there may be other constraints set up. For example in meals processing applications you will have limit on the types of chemical that can be applied.
The differential cost of each element may be the key to efficient cleaning. Optimising the mixture of elements is the process of increasing one element of the mix which has a less expensive (e.g. mechanical action) so that another element that has a more expensive (e.g. heat) can be reduced. The net cleaning power will stay the same however the cost linked to the cleaning procedure will be reduced.
Complete efficiency gains Whilst general efficiency can be gained by reconfiguring the contributions from every component it is clearly good for strive for efficiencies in every element. If, for instance, a cheaper method of heating can be found then this component in its right becomes more efficient, and thus the complete process is less expensive.
An absolute gain in a single element, however, may be better utilised by reducing the contribution from another more expensive element. For example, if a far more efficient heating method were found then either heat could possibly be maintained at the existing level for a lesser cost OR high temperature could be improved for the same price. If high temperature is increased then probably time could be reduced whilst keeping overall cleaning power at the same level. If the opportunity price saved by reducing cleaning cycle time is greater than the savings created by improved heating system efficiencies then this construction is optimum. Basically a gain in efficiency in one element isn't always best deployed in that element.
Maximising gains To be able to leverage hard received efficiency gains its is sensible http://query.nytimes.com/search/sitesearch/?action=click&contentCollection®ion=TopBar&WT.nav=searchWidget&module=SearchSubmit&pgtype=Homepage#/New Jersey to consider just how they are best deployed and how they might be utilized to re-configure the cleaning elements mix.
The importance of water efficiency - Water is money. The true cost of water is frequently under appreciated.
- Raw utility bill price per m3 of water
- Cost of filtering and sanitising if recycling clean off - Cost of caustics or various other cleaning fluids
Moreover if we decrease the water had a need to clean we can
- Lower Pump working costs (electricity) - Lower Maintenance costs - Longer life time for the pump. - Potentially use a smaller pump (reduced capex)
As the price of energy and water are both increasing, and more likely to continue steadily to increase, reductions in water usage have significant financial advantages to any organisation. Further more the green / environmental benefits are seen as a moral imperative by many organisations. Future green legislation is only more likely to boost the need for more efficient water usage.
The need for time efficiency - Time is money. It could be a cliché but it's still true. The time spent cleaning between production runs, whilst required, still represents downtime. The opportunity cost associated with this downtime will vary greatly depending on the application form, but in almost all cases a decrease on cleaning cycle period will have a direct financial benefit.
Chemical substance and heat efficiency - Generally there will be limitations in each of these elements. Probably more importantly both elements have very rapidly diminishing returns after a particular stage. For example, the cost associated with raising cleaning temperatures from 60o - 70o can be unlikely to be worth it for most applications. Chances are that chemical and temperature action will be the elements that are reduced in any efficiency drive. The typical scenario is that improved mechanical actions will result in the reduction of chemical usage or lowering the temperature of washing.
When performing these savings calculations it is important to remember the true cost of high temperature and chemicals. High temperature is relatively simple to calculate as it is essentially an energy cost but consideration should be directed at maintenance spares and overall capex vs working lifestyle of the heating system. The expense of using chemicals should obviously are the raw price of the chemical substance but also the expense of disposal of spent chemical substances and recycling plant costs (if used).
The Quick Win - Often the simplest absolute efficiency gains are available by enhancing the mechanical action element of the mix. These gains may then be deployed to lessen other components of the blend, if that is appropriate.
The importance of spray nozzle selection
For just about any impact cleaning process water serves two purposes. First of all it acts to dissolve residue - that is section of the chemical component of cleaning mentioned previously. More importantly, however, water may be the mechanism where the mechanical action element is delivered. The performance of a water spray for providing mechanical energy for cleaning will be greatly affected by the type of the spray and therefore the nozzle used.
Improving the performance of mechanical actions - Mechanical action is essentially the procedure of transferring energy from a pump to the top to be cleaned through water. Much like all energy transfer systems performance is less than 100%. Very much energy is definitely wasted but by reducing this waste materials through improved nozzle selection we can significantly improve the efficiency of the tank washing system. If this is achieved then we are able to reduce the quantity of energy/drinking water used and obtain the same degree of mechanical action.
Effective nozzle selection will obviously not directly affect pipe friction losses nonetheless it will affect losses of energy through liquid atomisation and turbulent flow.
Fluid atomisation
The procedure of breaking aside a fluid into droplets to create a spray pattern uses energy. This, once utilized, is then unavailable for cleaning the top in question. The benefits of an atomised spray are that it could be formed into a complete cone or flat enthusiast pattern providing the spray to a larger area, but this means that the entire energy transfer will end up being less because of the energy used in the procedure of atomisation.
Turbulence
Further energy will be lost in atomised sprays due to turbulent flow. In toned fan or complete cone spray patterns the droplets are moving in a less uniform path than in a solid blast of water. Whilst the whole fluid includes a definite direction the individual droplets could have a random, turbulent, element with their motion. This successfully wastes energy indicating the entire transfer of energy completely cone and flat enthusiast patterns is much lower than in solid stream nozzles.
So the most effective spray system will be solid stream jet followed by a set fan spray pattern and finally a full cone design (omni-directional spray nozzles can be considered as 360° full cone nozzles). Certainly the efficiencies gained can be considerable it is not untypical to require 10 times less drinking water per square meter being cleaned. The drawback of solid stream washing systems is certainly that they require a precise wash cycle period to cover the entire tank. This may increase clean cycle occasions thus adding to the cost associated with the time component of the cleaning procedure.
Designs of tank washing nozzle
Spray Balls
These nozzles are spheres with multiple holes making an omni-directional spray. Whilst the individual jets can happen to become solid stream spray patterns, in fact, when considered jointly, they are better approximated to cone design. In terms of general energy transfer performance spray balls are extremely inefficient. They do, however, have the advantage of being very inexpensive and can deliver a minimal impact rinse more or less instantly to the whole container.
Regular uses would include: rinsing of milk storage tanks, rinsing of fruit juice tanks, disinfecting rinses. For anything other than very light cleaning applications in little containers though it is likely that efficiencies could be gained by changing from spray balls.
Spiral Wide angle nozzles
These nozzles create a "cone" of spray up to 270° wide. This makes them suitable for cleaning tanks by inserting them near the top of the vessel. The spray is certainly cone and therefore inefficient at energy transfer but nevertheless offers significantly greater impact than spray balls per level of drinking water used. Spirals is highly recommended for low effect cleaning of little tanks.
Normal uses would include: rinsing and washing liquid containing vessels, rinsing of vessels containing soluble powders,
Multi-headed nozzles
Various nozzle manifold tank cleaners exist on the market. Several complete cone nozzles will be positioned on a single mind giving an omni-directional spray. Because multiple nozzles are getting used to produce more direct sprays the effect per volume of water is increased. However the individual sprays are still full cones and thus inherently inefficient. Such systems are ideal for small-moderate sized tanks that want light to moderate cleaning.
Standard uses would include: rinsing and washing liquid containing vessels, rinsing of vessels containing soluble powders,
Rotary Flat Fan Nozzles
These nozzles could have several toned fan sprays that rotate under the pressure of the fluid. The rotating flans will sweep the whole of the tank. As with static nozzles complete insurance happens only after a few moments but the nozzle spray should be working for while before any significant residue is usually removed. As a flat fan pattern is being used there is a moderately effective energy transfer producing a medium impact cleaning spray.
These nozzles tend to be the most efficient choice for little to medium sized tanks that have moderately persistent residues to remove.
Cleaning wine barrels, washing fermenting tanks, cleaning storage tanks of viscous liquids (e.g. syrups)
Rotary solid stream
These nozzles have 2,4 or 8 solid stream jets which rotate sweeping the within of the container. A gearing mechanism changes the angle of the rotation therefore over time complete cleaning of the tank is achieved.
These nozzles are by far the most energy conserving tank washers due to the solid stream jets being deployed. They are usually more costly than other types of tank washer but also for medium to huge tanks or tanks with persistent residues the additional capital expenditure is frequently payed for rapidly through efficiency gains.
Common uses include: cleaning mash tuns, cleaning cooking vats, cleaning large storage silos
Conclusions
Quick wins can often be found by looking at the mechanical action component of the cleaning mix. The performance of the mechanical actions delivery mechanism can frequently be improved by appropriate nozzle selection. This improvement in performance will mean the same contribution to over all cleaning may be accomplished using less water which water saving translates directly to a reduction in operating cost.
These gains could be further multiplied by considering how the 4 elements of the cleaning mix can be reconfigured. It may, for instance, be more good for decrease the heating and chemical components of the mix instead of use all of the efficiency gains to reduce water consumption. The optimum configuration of the combine will change from application to software but irrespective improvements in the mechanical actions element of the mix tend to be a quick earn with a payback time measured in weeks rather than months.
