Wash Heating

When quoting or specifying a wash system (whether it be a cubicle or conveyed tunnel washer), heating capacity can be an important factor. Too little and the machine will not attain the required temperatures, too much and the system can be wasteful – or result in the heating system dropping in and out too frequently.

There are several areas within a machine that need to be considered in order to ensure the equipment has enough heating to overcome the system losses. Firstly, the type and number of items to be washed per hour within the machine affects the amount of heat that is transferred to the products as they are subjected to the heated water.

For instance if a machine is to handle both plastic and stainless steel trays racks etc, then care has to be taken with the calculations, as the different materials will take differing amounts of heat energy from the liquid due to their relative specific heat capacities. So if the machine was achieving temperature, at maximum capacity, on steel trays for arguments sake, then it would struggle with plastics at the same given throughput weight.

Water flow and jet design are also contributing factors. On a re-circulated system, temperature is lost as soon as the water emerges from the jet, and the rate of heat loss is proportionate to the flow of the pump and jetting system. This however can also be controlled if the design of the jet and the pressure of the water is considered. The aim is to keep the water flow as full as possible, minimising atomisation at the jet tip, as this atomisation will increase the surface area of water exposed to the air, resulting in a greater heat loss. Correct jet system design will minimise this without compromising the required wash pressure. Jetting system design will be discussed in a later talk.

Heat transfer to the steel surfaces of the machine can also be reduced by minimising the time that the water has to return to the reservoir, so if the jetting can take place virtually above the reservoir, the heat transfer to the return trays (the sloping surface on which the water runs back to the tank) can be lower. If not, then this heat transfer must be allowed for in the system design but is quite often overlooked.

Extraction fans can also be a cause of undue and unexpected heat loss within a machine. The positioning of the fans can have a big impact of heat removal from the system. Extraction fans, on a tunnel type machine, should be positioned at the ends of the tunnel. This allows the fans to draw in fresh air from outside of the tunnel, creating a barrier for the hot water vapour, rather than drawing heat and excessive water from within the unit. Often it has been seen where extraction fans have been positioned at the centre of the machine, drawing vapour from directly above the tanks, with the argument that they only use a single fan. The false economy of this is that you are pulling excessive heat from the working area, and also inducing a cool air flow along the machine, again increasing the heat loss. In a cubicle unit there is no easy way around this, as the fan has to be within the work area, but programming when and how often the fan operates, can minimise the effects.

Heating systems should be designed so that there is little waste or excessive heat. There are several methods of recovering some of the heat lost in flues, and flash steam and condensate recovery in steam coil heating is generally used industry wide. In gas heated systems this can be difficult, as the dew point needs to be exceeded therefore there is a minimum temperature at which the gasses should leave the machine. Some manufacturers will claim that they use excess heat from a gas flue to heat other areas of the unit, for instance air knives. However if the system is designed correctly there should be no waste heat. Any extra energy that is taken from the gas heating system downstream of the tank coil has to be over and above that which the tanks need, to ensure the gasses are above the dew point temperature. So this is not free heat it is additional heat required. Often it is thought that if the machines are fed with heated water, then the heating systems within the machines can be reduced considerably. The answer to this is yes they can be reduced, but only slightly. Normally a machine can be filled with hot water and reduce the warm up time, but when running, the flow of water from mains should be minimised to reduce utility usage. The only flow should be top up water for that which is carried out of the system on the products, and possibly a rinse clarification flow (to dilute detergent residue from carry over), if the machine has a re-circulated final rinse. The heat energy in this minimal running flow is far outweighed by the heat losses to the jets and products, which is the largest heat losses in the system, so when running, the reduction in heat energy required, by providing hot top up water is small, possibly as low as 1-2% of the total usage.

Heating issues, or problems in maintaining liquid temperatures are ones that users can experience far too often, and the fact is when you have spent considerable funds on a machine that doesn’t quite get there, do you remove it from site and replace it with a capable unit? Very often not. The most you may expect is a cost reduction from the manufacturer, which in the long term will not overcome the compromises you may have to make.


Probably the most important feature of a washing system is the jetting itself. If you cannot effectively cover all areas of the product to be washed, then the efficiency of the system is compromised from the start. There are many systems on the market that are supplied “off the shelf” or have a standard jetting pattern that the manufacturers supply for a particular range of machine.

That is acceptable if you are looking for a general wash, but not if you are looking for an efficient clean.

If you take your domestic dishwasher for instance, the jetting is very general and relies on the ricochet effect to ensure surfaces are covered and cleaned. However this can take up to 2 hours to produce a result. In a food production facility you do not have this luxury, so the position of the jetting needs to be more targeted to reduce the time required to clean the products.

Mechanical action (jetting) and time are 2 of the 4 factors required for efficient cleaning. If we reduce the time required, then the mechanical action needs to increase/improve, and this is where good jetting design is paramount.

In a machine, either the product moves or the jets move in order to create the “wiping” action required to remove the debris. If the angle of incidence is too shallow or too great, then the effect you will get is varied, so if the jetting angles can be adjusted within the manifold design, then the optimum angles can be achieved.

Pump pressure and water velocity are also factors to be considered. Generally with normal flat fan or cone jets, the further away from the product, the less effect the jet has due to the atomisation of the water away from the tip. Atomisation reduces the cleaning effect and can also increase the heating costs due to heat loss by the atomised water.  A lower pressure will reduce the atomisation effect, but will not necessarily provide enough pressure to wash. A higher pressure may increase the atomisation effect and reduce the optimum distance, so each system needs to be designed to exploit this.  This can be easily demonstrated when using a high pressure hose to clean your car/patio. If you move the nozzle further away from the surface, the more atomisation you experience and less cleaning action, so there is an optimum distance for the most effective result.

This refers back to the previously discussed “Dustbin and Teacup” syndrome, where large and small objects are washed in the same machine. The jetting (unless specific or adjustable between products), can rarely suits both items.

At Unitech Washing Systems, each product is evaluated, and the jetting systems (and arrangements within the machines) are plotted on a computer and adapted to suit, giving an optimum cleaning efficiency.

Angle Too Shallow – Correct Angle – Angle Too Great

<—- Product Flow

In order to increase jetting efficiency further, consideration also has to be given to the delivery pipework. Smooth bore manifolds, with hygienic fittings (RJT or IDF fittings) offer continuous flow without obstructions within the bore, which can minimise silt and debris build up. Box section pipework, which can be found in some competitors’ machines, introduces flow disruption and sudden changes in direction, which can reduce the performance in the system, and is often difficult to clean thoroughly.

Flushing points located at the end of a pipe run should also be considered as a way of quickly cleaning the inside of the manifold pipework, without having to strip down the whole of the system, thus saving time and maintenance costs.

As you can see from the above image, efficient washing system jetting is not just a matter of throwing water onto a product – it is a little more involved. If designed correctly, you can maximise performance, improve machine cleanability, and minimise cost.


Dustbin and Teacup Syndrome

Generally, Washing Systems within most production facilities (although critical to the business in terms of hygiene and product safety), are often seen as a necessary evil. Space allocation for this discipline is generally minimal and budgets for equipment are fairly tight. Add to this the fact that washing systems are not seen as having an added value in terms of production, Technical Managers and Hygiene managers have a hard time in justifying the cost of a new machine.

Based on this, it is no wonder that when some financial allocation is made, buyers will try and employ the equipment to wash a greater range of parts/containers as they can in order to maximise its utilisation.

Although there are some machines in the range that will clean several parts at a time (such as pan/utensil washers) with good effect, larger items are a different matter, as these can rely on specific types of equipment in order to produce efficient wash results. The larger machines are also more expensive, so this is where clients can sometimes request that the unit washes several different type of container in the same machine to increase the cost effectiveness of the purchase. This is what we call (or our sales manager calls) the dustbin and teacup syndrome.

What is meant by this term? If you had a machine to wash a dustbin, to also wash a teacup in the same machine would be restrictive on handling and efficiency. Yes you can handle several different types of container in the same machine, but only as long as handling and washing on each container has no effect on the efficiency of washing all of the others. For instance the jetting position to wash a bin and the pressures required would be completely unsuited for the washing of a tea cup. The jet positions would not necessarily be in the correct location for both, and the supporting or conveying system to contain the teacup, may be restrictive on the washing and handling of the bin.

Can these be efficiently washed in the same machine?

It is sometimes difficult to tell the client that they are wrong to try and attempt this, and the natural thing to do for many manufacturers would be to try and accommodate the requests. However this can result in the customer installing a machine that is a “jack of all trades” and does not clean any of the components efficiently, or is more expensive than installing 2 bespoke units due to the complexity required to arrange or adjust settings to suit all. This will only serve to disappoint the client, and more importantly their superiors, who have put up the funds for the equipment, and can also give the machine a bad name.

So next time that you are in the market for a machine, it may be a good idea, if a wide range of products are required to be cleaned, to consider the positives and negatives of washing in the same unit. Can some of the items be cleaned in an alternate method (ie hand washed if only a few units required)? Can we justify an additional wash system for the small components? What is the critical item to be washed and quantity? – all relevant points, that in theory should be questioned by the equipment supplier if they are ethical, as once a commitment is made to purchase, it must be fit for purpose.

Partnership with CTG

Unitech Washing Systems Limited is proud to announce that it has partnered with Cleaning Technologies Group LLC (CTG) of Cincinnati U.S.A, to distribute our hygienic range of food industry washing systems and hygiene equipment within the United States. CTG have been building industrial parts washers for a wide range of industries for over 100 years, and with their experienced sales and aftermarket service teams, plan to provide not only equipment installation services, but complete aftermarket parts and maintenance packages for our equipment. CTG,s experience in washing systems and service, makes the partnership ideal for our customers, as it brings not only hygienic, reliable and robust equipment to the U.S food and beverage industries, but provides confidence in our equipment support. In addition to this Unitech Washing Systems will play an active role initially to generate enquiries and interest in the CTG group products within the UK and Europe. For more information on the CTG group equipment, please see the link on our “Products” page.

New Manufacturing Facility

Following the Growth and Success of Unitech Washing Machines, manufacturing has transferred to a separate facility, with full design and manufacturing capabilities, and new fabrication machinery.

A new company has been formed as “Unitech Washing Systems Limited” and is looking to continue the growth in its products and services. 2019 has started with a very healthy order book and with a reputation for Quality and Efficiency.

The future of Unitech Washing Systems looks set to be secure with new developments and designs in the pipeline. These are exciting times ahead.

Pan Wash Central!

Weigh Pan Washers

Unitech Washing Systems have increased production of their Pan Washer range to several units per month. Each machine is efficient at washing multi head weigher buckets, utensils and trays. The machines are also suitable for high care installations and incorporate hygienic design principles.

The machines can wash a wide range of components, and can be supplied with bespoke product baskets to ensure excellent wash qualities. Please contact us for more details on the full range.

New Website

Welcome to our new website. Unitech Washers invites you to explore our new website. This links back to our new group marketing strategy, so expect lots more to come. For more information on our group please view the Unitech Group site.

Our new site has been created with the customer experience in mind, the site includes many new features to help users quickly and easily navigate the site and find the right product or service that they require.

Visitors to the site can stay informed with the latest Unitech Washers updates through the news and case study pages. Please supply us with your email address in the relevant forms so we can keep up to date.

At Unitech Washers we aim to make your life easier, so whatever your requirements are get in touch.
01543 224608

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