FEATURE PUMPS, VALVES & ACTUATORS
Matt Hale, International sales manager, HRS Heat Exchangers, discusses the challenges faced by pumps in the food industry, and how the company’s piston pump has been designed to cope
oving products around during processing is an inherent need for
most medium and large-scale food manufacturers. The exact requirements obviously depend on many factors, however, they tend to fall into two types, products which can be pumped and transported in pipes and those which need to conveyed, usually by mechanical belts or similar systems. When it comes to pumping product,
problems can arise because the pumps have not been specifically designed for the applications or conditions which they are being used for. It is also worth remembering that it is not just simple liquids which can be pumped. With the right equipment and suitable pipework, a range of products including powders, pastes and mixtures of liquids and solids can also be pumped. There are a number of advantages to this approach, in particular the ability to avoid contamination of products during processing, as well as being able to maintain temperatures, viscosity, etc. One of the issues with pumping is the potential to damage product. The viscosity of different fluids can be affected, resulting in issues such as runny or separated sauces or unwanted churning of dairy products. For materials containing solids, for example fruit mixtures, the wrong type of pump can easily damage the solid fraction reducing quality or, at worst, removing the very aspect of your product which you are trying to preserve. Although the physical and behavioural properties of many foods are well documented, in complex cases it is necessary to understand the foodstuff in order to specify the right pump. The temperature of the product is
important as physical properties will vary with temperature. Viscosity is an important consideration, and information on particle size is also required. These could include anything from ground spices to whole fruits or pieces of meat, and everything in between. The chemical
composition, for example, is the material acidic, will also need to be known so that the most cost effective materials can be used to produce the pump. Amongst other things, the shear
KEEPING UP WITH COMPLEX FLUIDS M
The HRS BP Series Piston Pump features a hygienic design
sensitivity of the fluid reflects how likely it is to be damaged by the impeller of the pump. The physical characteristics of some products will change after exposure to high shear stresses - this may be beneficial in some circumstances (such as turning cream into butter) but not others (for example when producing cream). Vapour pressure will also need to be considered to prevent issues such as flashing or cavitation. As well as being designed to handle your product, the pump needs to fulfil the requirements of food handling equipment, such as Clean-in-Place (CIP) and Sterilise-in-Place (SIP). There are many different types of sanitary pump suitable for use in the food industry, including rotary lobe, rotary piston, reciprocating positive displacement, progressing cavity, peristaltic hose and air-operated double diaphragm designs, all of which have their positives and negatives depending on the nature of both the media and the process. Many years of providing difficult heat
transfer challenges in the food industry showed us that pumping products without destroying their integrity is as important as developing heat exchange solutions which maintain product quality. We therefore went back to the drawing board to develop a pump which could handle very delicate and viscous food stuffs without damage while working at high pressure in heavy duty applications in
Matt Hale, International sales manager, HRS Heat Exchangers
the food and pharmaceutical industries. The result was a purpose designed reciprocating positive-displacement pump: the HRS BP Series Piston Pump. Positive displacement pumps have an expanding cavity on the suction side of the pump and a decreasing cavity on the discharge side. Liquid flows into the pump as the cavity on the suction side expands and is forced out of the discharge side as the cavity collapses. The BP Series features a hygienic design which incorporates a separator fitted between the piston and the hydraulic chamber to ensure that there is no contact between the product chamber and the hydraulic oil. Once the pump is in operation, no part which comes into contact with oil comes into contact with the product. With an adjustable flow, which can range
Positive displacement pumps are suitable for use in cream production
from a minimum of 300l/hr to a maximum of 20,000l/hr, and a high pressure drop of up to 30 bar, the series is suitable for a range of high viscosity, shear sensitive and large particle containing fluids. Clap valves allow pumping of whole fruits or vegetables, and an alternative piston pump with a pneumatic cylinder can be supplied for low pressure applications of less than 5 bar.
HRS Heat Exchangers
www.hrs-heatexchangers.com
12 JULY/AUGUST 2017 | PROCESS & CONTROL
/ PROCESS&CONTROL
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61
