Joe White Enterprises

J White Enterprises LLC Is Pleased To Offer

Customized High Temperature Short Time Operator Maintenance User Manual

The High Temperature Short Time Pasteurization is the Most Regulated Food Processing System in America.

It is made up of many different components that work together to form one unit. These components are Bound Together, Inspected and Sealed by a Regulatory Agent to form a Legal Dairy Processing System. It must be Operated and Maintained under the guidelines of the GRADE A PASTEURIZED MILK ORDINANCE (PMO).

This Manual is created using the P&ID of Your High Temperature Short Time Pasteurizer. The Function and Operation of each Component is described in detail while following the flow from start to finish through the HTST.

This manual includes the HTST P&ID, the Index, and the Animated Version of the HTST P&ID Illustrating (Diverted Flow, Flush Flow and Forward Flow) will give the Operations and Maintenance Personnel a complete overview of the HTST System for which they are responsible.

An Example of an HTST P&ID; HTST Animation; Key Component List and descriptions of 5 Components are included below.

High Temperature Short Time Pasteurizer System Key Components Index

1. Supply Pump
2. Balance Tank Throttling Valve
3. Balance Tank
4. Regenerator Bypass Valve
5. Booster Pump
6. Raw Differential Pressures Sensor #1
7. Differential Pressure Controller #1
8. Regenerator Section #1
9. Separator Bypass / Feed Valve
10. Separator
11. Skim Hold Back Valve
12. Cream Hold Back Valve
13. Cream Out Meter
14. Cream Standardizing Meter
15. Cream Standardizing Valve
16. Skim Standardizing Valve
17. Regenerator #2 Drain Valve
18. Raw Differential Pressure Sensor #2
19. Differential Pressure Sensor #2
20. Regenerator Section #2
21. Timing Pump
22. Timing Pump Check Valve
23. Timing Flow Meter
24. Homogenizer
25. Pressure Relief Valve
26. Heater Section
27. Holding Tube
28. Digital Reference Thermometer (DART)
29. Safety Thermal Limit Recorder (STLR)
30. Flow Control Recorder
31. Flow Divert Valve
32. Leak Detect Valve
33. Pasteurized Differential Pressure Sensor #2
34. Pasteurized Differential Pressure Sensor #1
35. Chilled Water Cooling Section
36. Glycol Cooling Section
37. Vacuum Breaker
38. Pasteurized Hold Back Valve
39. Recycle / Discharge Valve
40. Recycle Drain Valve
41. Surplus Cream Meter
42. Surplus Cream Valve
43. Surplus Cram Balance Tank
44. Surplus Cream Pump
45. Surplus Cram Cooler
46. Balance Tank Water Valve

(1) Product Supply Pump

• The product supply pump transfers product from the Raw Silo Tanks to the HTST Balance Tank (3).
  • If this is a Fixed Speed Pump it will run at the same speed regardless of the level in the Silo Tank. If it is a Variable Speed Pump operating with a P.I.D. loop controller based on discharge pressure it will not start running until the level in the silo is below approximately 20’. It will then continue to increase in speed until the silo tank is empty.
• All centrifugal pumps have a designed flow rate at a given inlet head pressure (feet of head in the supply tank) and discharge pressure.
• The raw silo tanks can vary in height so the difference in suction pressure between a tall or a short; a full or an empty silo tank can be significant.
• The supply pump may have no problem supplying enough product to the Balance Tank (3) when the tank is full but when the level in the tank falls below approximately 6’ the pump could start to cavitate due to the loss of suction pressure.
• Each supply pump must be sized so that it can deliver the required flow with a minimum of suction head pressure.
• The Product Supply pump discharges against the Balance Tank Throttling Valve (2).

(2) Balance Tank Throttling Valve

• The Balance Tank Throttling Valve (2) is controlled by the Balance Tank Level Control P.I.D. Loop
• The Balance Tank Throttling Valve (2) keeps the product at a near constant level in the Balance Tank (3) to maintain a consistent suction pressure on inlet of the Booster Pump (5) or Timing Pump (21). This helps the pumps maintain a steady discharge pressure and flow rate.
• When the Silo Tank is full the Throttling Valve (2) will be closed almost all the way and when the Silo Tank gets near empty the Throttling Valve (2) will be wide open.
• The Throttling Valve Actuator (2) must have enough pressure to shut off against any supply pump pressure when closed.

(3) Balance Tank (Constant Level Tank)

• The Balance Tank (3) serves several purposes:
  • The HTST can be started on water and when it gets to temperature the level of the water can be lowered and product can be brought into the Balance Tank (3) to create a product separate.
  • By operating at approximately half full while in production the product held in the Raw Regenerator (8) can drain back into the Balance Tank (3) when the HTST goes into Diverted Flow without overflowing the Balance Tank (3).
  • This allows the Recycle / Discharge Valve (39) and Recycle / Drain Valve (40) to recycle product back to the Balance Tank (3) from the HTST while a new Discharge Tank is selected.
  • When the Raw Silo gets near empty the level in the Balance Tank (3) will drop to the recycle level and cause the Recycle / Discharge Valve and Recycle / Drain Valve to recycle product back to the Balance Tank (3) to keep a constant flow through the HTST while a new Raw Silo is selected.
  • It provides a reservoir for CIP solution re-circulation while the HTST is being cleaned.
• The overflow point of Balance Tank (3) must be below lowest level of Plate Heat Exchanger unit in order to allow the Raw Regenerator #1 (8) and Raw Regenerator #2 (20) to drain back to the Balance Tank (3) when in diverted flow.
• The Balance Tank (3) level is controlled by the balance tank level P.I.D. loop which is fed by the Balance Tank Level Sensor and controls the position of the Balance Tank Throttling Valve (2).
• The Balance Tank (3) has 3 set points based on percentage of level.
  • High level: Used to turn the water valve off and on when water is the supply and during CIP mode.
  • Recycle level: When product reaches this level the Recycle / Discharge Valve (39) and Recycle / Drain Valve (40) will energize allowing the system to go into re-circulation mode either from the Raw Silo level going low or the Discharge Tank selection being changed.
  • Low level: When product level reaches this point the next product selection will start coming into the Balance Tank (3). This can be another product or water, whichever is selected.

(4) Regenerator Bypass Valve

The Regenerator Bypass Valve (4) is a cross body-blocking valve which is normally open to both the Booster Pump (5) and Timing Pump (21).

• When the HTST is off the Regenerator Bypass Valve (4) is open which allows raw product to drain back from both Raw Regenerator #1 (8) and Raw Regenerator #2 (20) into the Balance Tank (3).
• When the HTST is running in diverted flow the Regenerator Bypass Valve (4) is de-energized, allowing product to flow from the balance tank through the bottom port directly to the inlet of the Timing Pump (21).
  • This allows the product to bypass the Raw Regenerator #1 (6) and go directly into the Heater (26).
  • The product will follow this path until pasteurization temperature is reached and the Flow Diversion Valve (31) and Leak Detect Valve (32) shift into forward flow.
• Once forward Flow temperature is reached the Flow Diversion Valve (31) and Leak Detect Valve (32) will shift into forward flow. When the Pasteurized Regenerator #1 (6) & Pasteurized Regenerator #2 (20) have at least 1^psi higher pressure than the Raw Regenerator #1 (8) & Raw Regenerator #2 (20) the Booster Pump (5) will start and Regenerator Bypass Valve (4) will close allowing product to enter into the inlet of the Booster Pump (5).
• The Booster Pump (5) will push the product through Raw Regenerator #1(8) raising the temperature to approximately 140⁰F and feeding it into the inlet of the Timing Pump (21).

(5) Booster Pump

The Booster Pump (5) is allowed to run when the following criteria are met:

• The Flow Diversion Valve (31) and Leak Detect (32) Valve are in forward flow position.
• The Timing Pump (21) is running.
• The pressure in Pasteurized Regenerator #1 and Pasteurized Regenerator #2 (20) is at least 1^psi higher than the Raw Regenerator #1 (8) and Raw Regenerator #2 (20).
• When the booster pump starts the Regenerator Bypass Valve (4) is energized, blocking flow from the Balance Tank (3) to the Timing Pump (21), allowing the Booster Pump (5) to supply product through the Raw Regenerator #1 (8) to the inlet of the Timing Pump (21).
• During start up the Booster Pump (5) will cycle off any time the Raw Pressure in either Regenerator comes within 1^psi of the Pasteurized Pressure in that Regenerator. The Pasteurized Pressure in the Regenerators is maintained by Pasteurized Hold Back Valve (38).
• The booster pump speed is controlled by a variable frequency drive that is adjusted manually. It is set to maintain an inlet pressure of at least 5 ^psi on the Timing Pump (21).
  • During CIP cleaning the speed will be increased to achieve the required CIP flow rate.