Knight Equipment 30 PSI Installation Manual

Theory of Operation: The Tortuous Path Metering Device (TPMD) uses a well known principle of fluid engineer-

ing to control small flows of liquid in a water driven system. Knight’s TPMD uses a small
molded plastic torpedo shaped device (referred to as a “Knuckle”) that has a molded fluid
path with 16 turns per 1/2 Knuckle and 32 turns in a full Knuckle.

It is the .014” channel with it’s twisting turns that provides resistance and reduces
the suction of the water driven venturi. The more turns in the tortuous path or
the more “TPMD” Knuckles placed in a supply tube the less chemical will be mixed with the
final solution.

The following procedures should be followed for KP1H Stations and KP1H Dial 4. These
instructions replace steps 6-8 on page 4 of the KP1H Manual P/N 0900875 Rev. B.

4. Attach the TPMD to the inlet barb of the venturi body.
Route the free end of the TPMD tube through the
opening at the bottom of the backing plate.

For a Dial 4 setup, connect the remaining TPMD to
the chemical inlet port on the Dial 4 venturi. Then
route the tubes through the backing plate.

5. Attach one end of the black barb fitting to the 3/8”
chemical supply tube. Attach the other end of the
barb fitting to the TPMD.

For a Dial 4 setup, attach the remaining barb fittings
to the supply tubes and TPMD assembly.

6. Replace the cover on the KP1H Unit.

KP1H Station and Dial 4

1. Remove the cover by loosening the screws near the bottom of
the proportioner. Then lift the cover up and out using the
open slot at the top of the cover. Remove the actuator and fill
tube spout is used.

For a Dial 4, the D4 Selector must be at the 12 o’clock
position for the cover to be removed.

2. Select the appropriate TPMD assembly for the dilution

rate desired. Refer to the Dilution Ratio Chart on the
following page.

3. Twist the supply tube spring over the TPMD assembly.

Be sure to attach the spring on the end of the TPMD
assembly nearest the TPMD Knuckles.

For a Dial 4 setup, spring is not used.

Tortuous Path Metering Device Installation

Opening of Backing Plate

Barb Fitting

1/2 Knuckle

Full Knuckle

Tortuous Path P/N 0900873 Rev. Rel.

1 GPM Flex Gap

DYNAMIC WATER PRESSURE

1 GPM Aire Gap

4 GPM Flex Gap

3 GPM Aire Gap

DILUTION

512:1

512:1

512:1

750:1

935:1

1400:1

512:1

750:1

935:1

1400:1

30 PSI

P/N 2201221-35
Tortuous Path Metering Device
3

1/2

Knuckles

P/N 2201221-40
Tortuous Path Metering Device
4 Knuckles

P/N 2201221-05
Tortuous Path Metering Device
1/2 Knuckle

P/N 2201221-10
Tortuous Path Metering Device
1 Knuckle

P/N 2201221-15
Tortuous Path Metering Device
1

1/2

Knuckles

P/N 2201221-25
Tortuous Path Metering Device
2

1/2

Knuckles

P/N 2201221-15
Tortuous Path Metering Device
1

1/2

Knuckles

P/N 2201221-15
Tortuous Path Metering Device
1

1/2

Knuckles

P/N 2201221-25
Tortuous Path Metering Device
2

1/2

Knuckles

P/N 2201221-50
Tortuous Path Metering Device
5 Knuckles

40 PSI

P/N 2201221-30
Tortuous Path Metering Device
3 Knuckles

P/N 2201221-30
Tortuous Path Metering Device
3 Knuckles

P/N 2201221-05
Tortuous Path Metering Device
1/2 Knuckle

P/N 2201221-10
Tortuous Path Metering Device
1 Knuckle

P/N 2201221-15
Tortuous Path Metering Device
1

1/2

Knuckles

P/N 2201221-25
Tortuous Path Metering Device
2

1/2

Knuckles

P/N 2201221-10
Tortuous Path Metering Device
1 Knuckle

P/N 2201221-20
Tortuous Path Metering Device
2 Knuckles

P/N 2201221-25
Tortuous Path Metering Device
2

1/2

Knuckles

P/N 2201221-40
Tortuous Path Metering Device
4 Knuckles

50 PSI

P/N 2201221-25
Tortuous Path Metering Device
2

1/2

Knuckles

P/N 2201221-25
Tortuous Path Metering Device
2

1/2

Knuckles

P/N 2201221-05
Tortuous Path Metering Device
1/2 Knuckle

P/N 2201221-10
Tortuous Path Metering Device
1 Knuckle

P/N 2201221-15
Tortuous Path Metering Device
1

1/2

Knuckles

P/N 2201221-25
Tortuous Path Metering Device
2

1/2

Knuckles

P/N 2201221-10
Tortuous Path Metering Device
1 Knuckle

P/N 2201221-20
Tortuous Path Metering Device
2 Knuckles

P/N 2201221-20
Tortuous Path Metering Device
2 Knuckles

P/N 2201221-35
Tortuous Path Metering Device
3

1/2

Knuckles

DILUTION RATIO CHART

Mixing Ratios should be used for reference only. Ratios and flow rate will vary depending on water pressure,
chemical viscosity and length of chemical lines.