Thermal equipment company tackles sticky problem presented by nut butters
A popular trend necessitated some ingenuity for a supplier of industrial thermal technology equipment. Nut butter products are popping up on grocery shelves everywhere — from almond to macadamia to pecan, available in gluten-free, peanut-free or plant-based.
While the variety is vast, including even seed butters, the plethora of products share one common challenge: All nut butters are quite viscous, turning almost solid at low temperatures, and difficult to move through processing machinery.
Peanut butter is at least five times thicker at room temperature than tomato ketchup and becomes even more viscous at colder temperatures, according to HRS Heat Exchangers, a global thermal technology equipment designer and manufacturer based in the U.K.
Adding stabilizers, such as partially hydrogenated vegetable oils, to prevent oil separation can worsen the problem, as the additives form a crystalline structure with higher viscosity levels.
HRS Heat Exchangers confronted the dilemma firsthand when a client ordered the company’s R Series Scraped Surface heat exchanger for processing a nut butter line.
“Although the R Series is purposely designed for viscous materials, some very solid materials — like low temperature peanut butter, — were a step too far,” Matt Hale, HRS global key account director, said. “The thickness of the cold nut butter was beyond the parameters of the R Series gearbox and its mountings, and the unit we were testing failed.”
That experience drove the company’s research and development team to find a solution. The result is the HRS RHD Series for heavy-duty applications.
The new solution maintains the benefits of the standard series, including the continuous scraping action to enhance the mixing of viscous products and a sealing system which allows for the removal of individual tubes for cleaning or maintenance. But the heavy-duty series also boasts increased strength and durability, with a motor size expanded from 4 kW to 7.5 kW.
The gearbox size was also enhanced and the scraping rod was made bigger and stronger, with heavy-duty bearings and lip seals to accommodate increased torque. Further along the tube, an extra support for the scrapers was added to cope with the weight and increased forces, while an extra external support was added to the motor end of each RHD unit to cope with the extra weight.
“The standard R Series of rotating scraped surface heat exchangers from HRS Heat Exchangers have been proven time and time again, in both food and hygienic applications, for their ability to reliably process viscous products such as sauces, purees, creams and gels,” Hale said. “With the addition of the HRS RHD Series, we can now deliver these benefits to the thickest and most difficult to handle materials, such as nut butters or any semi-solid product.”
HRS Heat Exchangers explained more about the creation of the heavy-duty solution in answers to emailed questions from Produce Processing.
WHAT SPECIFIC PROCESSING CHALLENGES DO NUT BUTTERS PRESENT?
HRS: Because of their highly viscous, thick nature, particularly at low temperatures, nut butters are particularly likely to cause fouling on the internal surfaces of tubular heat exchangers. To overcome this, scraped surface heat exchangers (SSHEs) are required.
However, because of the thickness of the product, nut butters also place a considerable strain on the mechanical components of SSHEs (e.g. motors, bearings, gearboxes, etc.). This can lead to poor performance, shorter service intervals or equipment failure.
HOW DO THE HRS RHD SERIES AND OTHER HRS SOLUTIONS ADDRESS THOSE CHALLENGES?
HRS: To overcome the heat transfer and fouling challenges, HRS recommends a rotary SSHE such as the HRS R Series. To prevent the mechanical issues described above, HRS developed the heavy-duty HRS RHD Series, which features increased motor size and larger, stronger scraping rods. It also features extra mounting supports for the scrapers and motor, enabling the unit to be used under challenging conditions.
The development of the RHD came about due to our years of experience of clients using the standard R Series for extremely viscous products such as nut butters.
CAN IT BE USED TO ADDRESS OTHER INDUSTRY CHALLENGES?
HRS: The standard R Series has a wide range of applications where a rotary SSHE is required. The RHD Series can be used for any application where products with extreme viscosities are involved.
With the R3 we offer a multi-tube option, so for footprint and Opex there are significant savings to be made over single tube SSHEs.
WHAT HAS BEEN THE CUSTOMER REACTION TO THE HRS RHD SERIES?
HRS: So far so good, as we can offer solutions we couldn’t before. As with all HRS products, there is a performance guarantee.
