Page 62 - FoodFocusThailand No.175 October 2020

SOURCE OF ENGINEER

Pump and valve in the food industry
generally have two main types, one
for a processing plant and the other
for utility system. The equipment
for the utility system has many
standards and pricing levels to
match particular requirement
from the designer or the buyer.
The selection can be chosen
to meet the budget, or together with the
company policy.

Pump and ValVE year may not be practical for a premium-expensive

one. The investment cost of 2-3 times folded may be
too excessive.
for Food Industry actual usage. A single or double mechanical seal
5. Mechanical seal must be considered from an
should be considered from requirement such as
crystallization, high viscosity, sterilization, and etc.
When selecting a double mechanical seal, it gives a
greater flexibility; however, there is a weakness too.
The equipment in food processing plant is required to meet hygienic equipment design. When there is a lack of lubricant, the seals can be
Firstly, both pump and valve must comply with this primary principle. Then, the equipment damaged easily. In contrary, if the pressure of
capability, cost, and maintenance expenditure shall be later considered. lubricant is too high, it can leak and contaminate the
product unexpectedly.
Hygienic Equipment Design and Installation
1. Equipment materials in a direct or indirect contacting with food must not deteriorate, The processing valve must be
corrode, or be reactive when operating with all kinds of products or raw materials in the considered the following parameters
process. This required property includes the resistant capability to cleaning chemicals, 1. Product characteristics must be considered
disinfectants, pressure, temperature, water quality used in factories. In many occasions, such as particular, dimension, size, particle proportion,
material corrosion arises when the selection does not take into account for all manufacturing and etc. Those factors have a great influence to select
process. A negligent or an improper installation at the first place may cause huge damages a valve type which can damage the product directly.
after all. Or, there might be a contamination due to a residual
2. The surface roughness of direct contact to products must contain value of Ra ≤ 0.8 accumulation at the gasket, or valve seat.
μm. If the surface roughness is higher, it will be a harbour trapping a residual of products 2. The main function of valve is to open-close
or substances. In consequence, it is difficult to clean, and it can be a source of microbial action, regulate a flow rate, or to generate back
accumulation. pressure in the system. Each valve has a different
3. The cleanability is the indicator shown how easy the machine can be washed in all characteristic. For example, a butterfly valve cannot
contacting area. The European Hygienic Engineering & Design Group (EHEDG) identifies adjust a direct variation of flow rate; however, it
the criteria of testing and certification to equipment . They are classified by the wet or dry creates different pressure drop from each valve
1
cleaning methods according to the operation i.e. Cleaning In Place (CIP), Cleaning Out of design.
Place (COP), or Aseptic. 3. The position to install a valve affects its
This preliminary principle is the foundation for most process equipment including tanks, performance. Some valves may become a dead end
pipes, fittings, heat exchangers, filling machines, process equipment, and all related parts of the system. Plus, temperature changed in one side
involving the production quality. of valve can directly affect a product quality.
4. The valve position must take in the consideration.
The processing pump must be considered the following parameters The valve can be supplemented, or resistant to the
1. Product characteristics must be considered such as the range of max-min temperature, system process by the pressure force. This will cause
viscosity, pH, corrosive material, crystallization, particulate, texture denaturation, an extra effort, cause a leak, or force a valve to stay
crystallization, shear resistance, and so on. opened due to a high pressure in the system. As a
2. The flow rate must be considered at all aspects in production cycle. A particular piping result, an unanticipated contamination can be
point may encounter more than one flow property. For instance, the flow rate changes in occurred.
CIP process, or the circulation flow rate with mixing tank make a different flow rate at the Pump and valve in the market are varied,
ending discharge. In addition, when the ending discharge switches on and off, the pump complex, and price differentiated. Therefore, the
must be capable to cope with a high velocity. This condition can raise product’s temperature; selection must be based on the criticality and the
therefore, the product property may change its characteristic later on. actual operation to make the best cost effectiveness.
3. Discharge pressure of pump must be considered with the maximum load, then plus Moreover, the installation is also an important factor.
15-20% motor upsizing. However, the size should not be too high or over designed. Then, An improper or unhygienic installation will not only
it may cause a water hammer issue to damage valves and piping system. Also, the energy trigger an ineffectiveness, but also fail a product
consumption may be overburdened. quality with a higher cost of production.
4. Pump performances from various brands are not the same. The pump characteristic
depends on the detailed design, motor efficiency, and assembly quality. Those factors result
in the different power consumption and the life expectancy. The selection process must ข้้อมููลเพิ่่�มูเติ่มู/Additional Information
consider annual operating hours too. For instance, the pump operating only few hours a 1 สามารถตรวจสอบการรับรองอุปกรณ์์ต่างๆ ได้้จาก
www.ehedg.org
1 For the criteria of testing and certification of equipment,
62 FOOD FOCUS THAILAND OCT 2020 please visit www.ehedg.org

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