1-805-484-2992
Quotes - Engineering - SalesOne heater, several skid layouts
The tank arrangement decides how hard the heater works
A CIP skid is one to four tanks, a supply pump, a return pump, a heater and a valve matrix. Single-tank skids rinse and wash from the same tank. Two-tank skids hold rinse water and wash solution apart. A third tank recovers final-rinse water for the next pre-rinse, and a fourth holds concentrated caustic, acid or sanitizer for dosing. One-pass systems dose chemical into the supply line and heat it once as it leaves the skid; multi-pass systems hold solution at strength in the tank and reheat it every circuit.
The parent page sizes the heater on the cycle clock. This page is about the heater itself: where it sits, its steam side, its ratings, and how the tank count sets the duty.
The heater on a sanitary CIP skid
Where the heater sits and what it feeds
The heater sits in the supply line between the pump and the valve matrix, so every circuit gets solution at temperature whichever tank it came from. Downstream the solution goes to spray balls at 20 to 30 psi, to rotary spray heads at 60 to 100 psi where impact matters, and through pipe circuits and process exchangers at 5 ft/s. The solution side is rated for the pump at shutoff, because a closed valve in the matrix puts the full head on the shell.
The solution side is 304 or 316L, 32 Ra, tri-clamp, drainable to a low point and vented at the top, with a removable U-tube bundle so the shell can be inspected after years of caustic.
The steam side
Plant steam at 15 to 50 psig enters the tubes through a modulating valve controlled on the outlet RTD and leaves through a trap sized for the start-up condensate load, three to five times the steady load. A vacuum breaker on the inlet lets the tubes drain when the valve closes; without it the bundle floods, the next cycle opens the valve onto standing condensate, and the hammer cracks a tube joint. Steam-side rating is 150 psig at 375 F.
- Modulating valve sized on the start-up load, with a 2 to 3 degree band on the outlet
- Trap with a strainer and a check valve, condensate line never lifted more than the steam pressure allows
- Vacuum breaker at the inlet, drain at the tube-side low point
Single-tank versus multi-tank duty
On a single-tank skid the heater does everything: rinse water to 100 to 140 F, then caustic from ambient to 170 F, then acid to 150 F, with no tank held warm between them. It is sized on the caustic rise at full circuit flow and runs flat out for the whole cycle. On a two-tank or three-tank skid the solution tanks are held at 120 to 140 F by a small recirculation heater, and the in-line heater trims the last 30 to 50 degrees; it can be a third the size for the same plant.
One-pass dosing systems have no warm tank, so the heater sees the full rise at full flow every cycle. HeatX asks for the tank count and phase sequence before quoting because the answers move the heater size by a factor of three. Complete sanitary CIP heater packages are covered on our sanitary CIP heat exchanger pages.
The common mistake
Sizing on the boiler nameplate pressure and not the pressure the skid sees when the pasteurizer, the deaerator and the evaporator all draw at once. A heater sized on 50 psig that gets 12 psig at peak has lost a third of its temperature difference and delivers 150 F caustic to a circuit validated at 170 F. HeatX sizes on the lowest steam pressure the skid will see and states it on the drawing.
Call and talk it through with an engineer: 1-805-484-2992
Sanitary CIP heater conditions
A CIP heater is sized to the chemistry and the cleaning steps it serves. Use the rows to compare your own cycle, and send the largest line size and steam pressure along with the quote request.
| Condition | Detail |
| Fluid | 1 to 2 percent sodium hydroxide; 0.5 to 1 percent nitric or phosphoric acid; rinse water; peracetic sanitizer |
| Flow range | 30 to 600 gpm, set by 5 ft/s in the largest line on the circuit |
| Temperatures in / out | Caustic 120 F to 160 to 180 F; acid to 140 to 160 F; pre-rinse 100 to 140 F |
| Hold | 20 to 40 minutes caustic, 10 to 20 minutes acid, held by return temperature |
| Utility | Plant steam at 15 to 50 psig, modulating valve, trap, vacuum breaker |
| Approach | Not limiting on steam; outlet held within 2 to 3 degrees of setpoint |
| Construction | U-tube, steam in the tubes, solution on the shell; straight tube where the plant wants brushable solution tubes |
| Finish / class | 304 or 316L on the solution side, 32 Ra, tri-clamp connections, drainable; 3-A symbol where the inspector asks |
| Ratings | Solution side to the pump shutoff head; steam side 150 psig at 375 F |
| CIP / SIP | The heater is cleaned by the cycle it heats; drained and vented between cycles |
Operating Questions
Because the valve opens wide onto a cold bundle and the outlet RTD reports what happened several seconds ago. The steam side has stored energy; the solution side has lag. A feedforward term from supply flow, a ramp on the valve opening over the first minute and loop tuning on the running skid rather than at vendor defaults usually hold the band to the 2 to 3 degrees the drawing promises. The overshoot is not harmless: a 185 F excursion on seals rated for the program is life taken off every gasket in the circuit, every cycle.
Read a pressure gauge on the tube side downstream of the control valve with the valve wide open. If it reads near header pressure and the outlet still falls short, the problem is inside: air, condensate from a failed trap or vacuum breaker, or a film on the solution side. If it reads far below header pressure, the valve or the supply is the limit and cleaning the heater will not help. At 12 psig the steam is at 244 F, so a heater that needs 170 F caustic has only 74 degrees of difference at the outlet against 128 at the 50 psig the drawing assumed. The gauge costs little and settles the argument in a minute.
Test the trap, clean its strainer, and prove the vacuum breaker opens. A trap stuck closed floods the bundle and the next start hammers it; a trap stuck open passes steam and hides the problem until the fuel bill. The trap is picked for the start-up load, 3,900 to 6,500 lb/h on a heater rated 1,300 lb/h steady, so a trap replaced on the steady load floods on the first cold start. At a planned shutdown, pull the U-tube bundle and look at the outside of the tubes near the tubesheet, where caustic sits if the shell drain is not the true low point.
Yes, if the steam pressure at the skid leaves enough temperature difference above the sanitize setpoint. A hot water sanitize at 180 to 190 F on 15 psig steam at 250 F has 60 to 70 degrees of difference, which a heater sized for 170 F caustic reaches, but slowly, so the ramp eats into the hold. State the sanitize temperature, hold time and flow when the heater is quoted and it is sized for the harder of the two duties.
An independent high-temperature switch on the solution outlet closing a separate block valve on the steam supply. A high alarm on the RTD that runs the control loop shares it's failure. With 50 psig steam a stuck valve walks the solution toward 298 F saturation, at or past the rating of most EPDM compounds, flashing at the spray balls and softening any plastic return line. The solution-side relief valve covers pressure and does nothing about temperature.
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